THE DEVELOPMENT OF A GENERIC WATER SAFETY PLAN FOR SMALL COMMUNITY WATER SUPPLY

Peter Thompson & Sameera Majam

Report to the Water Research Commission

by

Umgeni Water

WRC Report No. TT 415/09

August 2009

ii

Obtainable from Water Research Commission Private Bag X03 Gezina 0031 The publication of this report emanates from a project entitled Compilation of a generic safety plan for small community water supply (WRC Project No: K8/649//3).

ISBN 978-1-77005-881-1 Printed in the Republic of South Africa

DISCLAIMER

The report has been reviewed by the Water Research Commission (WRC) and approved for publication. Approval does not signify that the contents necessarily reflect

the views and policies of the WRC, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.

iii

TABLE OF CONTENTS LIST OF FIGURES ........................................................................................................................ iv LIST OF TABLES .......................................................................................................................... iv LIST OF ABBREVIATIONS ........................................................................................................... iv SECTION 1: INTRODUCTION .................................................................................................... 1 1.1 BACKGROUND ..................................................................................................................... 1 1.2 CURRENT METHODS OF ASSESSING WATER QUALITY ................................................ 2 1.3 CONSTRAINTS OF USING INDICATORS TO PREDICT RISKS ......................................... 2 1.4 BENEFITS OF USING THE WATER SAFETY PLAN ........................................................... 3 SECTION 2: METHODOLOGY ON HOW TO DEVELOP A WATER SAFETY PLAN ................. 5 2.1 ASSEMBLE A TEAM TO CARRY OUT THE WATER SAFETY PLAN ................................. 5 2.2 DOCUMENT AND DESCRIBE THE SYSTEM ...................................................................... 6 2.3 ASSESS THE EXISTING PROPOSED SYSTEM (INCLUDING A DESCRIPTION OF

THE PROCESS AND A FLOW DIAGRAM) ........................................................................... 6 2.4 UNDERTAKE A HAZARD ASSESSMENT AND A RISK CHARACTERIZATION TO

IDENTIFY AND UNDERSTAND HOW HAZARDS CAN ENTER INTO THE WATER SUPPLY ................................................................................................................................ 8

2.5 IDENTIFY CONTROL MEASURES – THE MEANS BY WHICH RISKS CAN BE CONTROLLED .................................................................................................................... 10

2.6 DEFINE MONITORING OF CONTROL MEASURES – WHAT LIMITS DEFINE ACCEPTABLE PERFORMANCE AND HOW THESE ARE MONITORED .......................... 13

2.7 ESTABLISH PROCEDURES TO VERIFY THAT THE WATER SAFETY PLAN IS WORKING EFFECTIVELY AND WILL MEET THE HEALTH-BASED TARGETS ............... 15

2.8 DEVELOP SUPPORTING PROGRAMMES ........................................................................ 15 2.9 PREPARE MANAGEMENT PROCEDURES ...................................................................... 16 2.10 ESTABLISH DOCUMENTATION AND COMMUNICATION PROCEDURES ..................... 20 2.11 REVIEW OF THE WSP ....................................................................................................... 20 SECTION 3: CHECKLIST FOR CONDUCTING A WSP .............................................................. 21 SECTION 4: REFERENCES ........................................................................................................ 22 ANNEXURE A: RISK ASSESSMENT FORM ............................................................................... 24 ANNEXURE B: CORRECTIVE ACTIONS .................................................................................... 34

iv

LIST OF FIGURES Figure 1: Constituents that must be measured at different points in the supply system when

assessing water quality .................................................................................................. 3 Figure 2: Steps used to guide an assessment of water supply based on the WSP approach ........ 4 Figure 3: Institutional framework for the provision of potable water in South Africa ........................ 5 Figure 4: Symbol chart for drawing flow diagrams of water treatment systems .............................. 7 Figure 5: An example of a flow diagram for a system ..................................................................... 7 LIST OF TABLES Table 1: Factors for consideration during the documentation and description of the system ......... 6 Table 2: Sources of potential hazards or hazardous events in the water supply system ................ 9 Table 3: Risk Assessment Matrix ................................................................................................. 10 Table 4: Risk profile based on score calculated from risk assessment matrix .............................. 10 Table 5: Factors for Consideration ............................................................................................... 12 Table 6: Suggested sampling types and frequencies based on population served ...................... 14 Table 7: Incident Management Protocol for Health Related Drinking Water Quality Incidents ..... 17 Table 8: Incident Management Protocol for Aesthetic Drinking Water Quality Incidents .............. 19

LIST OF ABBREVIATIONS Cl2 - Chlorine gas CO2 - Carbon Dioxide DBPs - Disinfection By-products Fe - Iron GAC - Granular Activated Carbon HTH - Granular disinfectant chemical (sodium hypochlorite) MIB - Methyl-iso-borneol Mn - Manganese PAC - Powdered Activated Carbon UV - Ultraviolet WSPs - Water Safety Plans

1

SECTION 1: INTRODUCTION 1.1 BACKGROUND Since 1994, the South African government has directed its resources to ensure that the millions of under-serviced people in the country have access to a functioning basic water supply. To date, government has managed to provide clean, safe water to a total of 18.7 million people and in doing so has exceeded the Millennium Development Goals (Hendricks, 2008). Water service delivery demands have resulted in an exponential growth of small treatment plants in the country with many of these being situated in rural areas and with limited technical support. Management of these water supply systems has been very difficult and Water Service Authorities have to rely on limited resources to ensure that the water supply meets the minimum standards in terms of quantity and quality. As a developing country, South Africa faces many challenges in terms of providing water that meets the minimum standards for acceptable drinking water. These challenges are a result of: Unplanned development – Informal housing settlements in the resource area and in

urban/semi-urban areas make it difficult to control activities in the catchment area and to locate supply mains.

Poor sanitation – Poor access to urban sanitation, especially from the informal housing settlements, may result in the contamination of the water source and may also lead to the potential cross contamination of water pipes.

Locality (geographic factors) – Some plants are situated in rural areas and may not have sufficient finance and/or equipment resource availability to measure the appropriate water quality parameters.

Lack of system knowledge and technical skills – The operators and staff at water treatment plants do not have the proper qualifications and technical training required to run a plant.

Limited data availability – Many systems have only recently developed the culture of data collection and storage.

Socio-economic factors – A large percentage of the South Africa’s population are at/below the low income mark and are most likely to use contaminated water sources as they cannot afford to access better quality water sources. Some cannot afford, or do not know how, to conduct treatment within their homes, i.e. disinfection with a chlorine solution, e.g. Jik. This population group is at the greatest risk of infectious disease and illness from poor water supply.

Although water service delivery in South Africa has reached great milestones, the quality of water produced according to drinking water quality standards cannot always be ensured. This is evident by the amount of outbreaks that have occurred over time. The most recent incidents include: Bloemhof – 2006, Delmas – 2005 and Kanana – 2004. A recent survey of disinfection efficiency at 181 small drinking water treatment plants across South Africa revealed the following critical findings: Turbidity values at the point of consumption indicated that 46% of plants were compliant

within Class I and 41% were compliant within Class II of SANS 241:2006. Free chlorine concentrations at the point of consumption indicated that 32% of plants were

below 0.1 mg/L and 48% below 0.2 mg/L. The ideal target range according to SANS 241:2006 is between 0.2 and 0.5 mg/L.

At the point of consumption, 63% of plants were compliant for total coliforms and 66% were compliant for faecal coliforms.

The majority of operators lack relevant technical skills and appropriate training for plant operation. Their qualifications range from 24% with grade 10, 56% with grade 12 to 20% post grade 12.

2

Most plant supervisors and operators had no knowledge of flow rates at which plants operated.

Chemical dosing rates were determined by experience. The absence of a water quality monitoring programme in most plants was prominent. Some

plants use an external monitoring group at least once a month but do not receive regular feedback.

The maintenance of equipment in some plants was not taken into account. According to the survey (Momba, 2007), the shortfalls noted were due to various issues, i.e. poor maintenance practices, lack of training and capacity building, poor working conditions, insufficient financial capacity and poor recording, documentation and communication. 1.2 CURRENT METHODS OF ASSESSING WATER QUALITY Water quality assessments are conducted by the measurement of certain physical, chemical and microbiological constituents at different points in the water supply system, i.e. water source, treatment works, distribution system and point of use (WHO1). There are many constituents present in water but only those that occur in concentrations high enough to cause health and aesthetic problems are most important and are measured frequently. During a water quality assessment, tests are conducted for features referred to as general indicators that warn of potential problems in water quality. These are: conductivity, faecal coliforms, pH, turbidity and free chlorine (DWAF et al., 2001). Various other constituents can be measured to assess water quality. These constituents are listed in Figure 1 and are arranged in order of decreasing priority from Group A to Group D (DWAF et al., 2001). The frequency of monitoring is dependent on the size of population served. 1.3 CONSTRAINTS OF USING INDICATORS TO PREDICT RISKS Water quality assessments are more focused on the control of the means of measurement rather than ensuring that operational practices are consistent with producing water that meets the requirements of SANS 241. The elimination of pathogenic micro-organisms in the water supply is given higher priority in water quality control even though several other factors that lead to poor water quality are existent. The original development of water quality control has placed major emphasis on the control of bacterial diarrhoeal diseases such as cholera, typhoid and shigellosis (Chapman and Hall, 1992). Bacteria are agents that cause severe acute disease and are important to consider as they account for a sizeable proportion of cases of diarrhoeal disease in both developed and developing countries. Within developing countries, epidemics of diseases caused by bacterial pathogens remain widespread. The major disadvantage of using indicators is during the microbiological determination of water quality. The methods used for microbiological determinations are based on detecting organisms (coliform bacteria) which are indicative of the presence of faecal pollution. If evidence of faecal material in the water is detected, it is assumed that pathogens may be present (DWAF et al., 2001). By the time pathogens can be detected, there is a strong possibility that water containing these pathogens has already been consumed and disease may therefore have been initiated. This approach would therefore limit the potential for preventative action to be taken (Chapman and Hall, 1992). Reliance on end product testing is risky because it gives limited warning of water quality deterioration and therefore impedes the implementation of preventative actions.

3

Source: DWAF et al., 2001

Figure 1: Constituents that must be measured at different points in the supply system

when assessing water quality

1.4 BENEFITS OF USING THE WATER SAFETY PLAN Water safety plans (WSPs) are a form of water quality assurance through a multi-barrier concept (WHO2). The multiple barrier principle implies that actions are required at all stages in the process of producing and distributing water in order to protect water quality. This includes source protection, treatment (when applied) through several different stages, prevention of contamination during distribution (piped or non-piped) and maintenance within households. The role of indicators is seen as primarily being a means of verification of the WSP in meeting water quality objectives rather than as a routine tool for monitoring water quality (WHO2). A WSP provides an organised and structured system to minimizethe chance of failure through oversight or management lapse. The process provides consistency with which safe water is supplied and provides contingency plans to respond to system failures or unforeseeable hazardous events. Water safety plans can be developed generically for small supplies rather than for individual supplies.

Group B

Nitrate/nitrite Fluoride Sulphate Chloride Arsenic Total coliforms The presence/concentration of these substances should be measured before water is supplied as they may lead to health problems. Frequency of testing is dependent on the source, treatment applied and the population served.

Group A

Conductivity Faecal coliforms pH Turbidity Free chlorine These are indicators of potential problems and should be frequently tested at all points in the water supply system. Free chlorine can be measured only once water has been treated with chlorine-based disinfectants.

Group D

Manganese Zinc Iron Potassium Sodium Magnesium Calcium Hardness

Substances that are commonly present that cause aesthetic or

economic concern only. Should be measured when assessing water

quality for the first time or when there is reason to believe that water quality

has changed.

Group C

Cadmium Copper These substances occur less frequently but may lead to health problems. (Should be tested at point of use).

4

A Water Safety Plan includes three key components (WHO2): System assessment – determines whether the drinking water supply chain (up to the point

of consumption) as a whole can deliver water of a quality that meets health-based targets. Identifying control measures in a drinking water system that will collectively control identified

risks and ensure that health based targets are met For each control measure identified, an appropriate means of operational monitoring should be defined that will ensure that any deviation from the required performance is rapidly detected in a timely manner.

Management plans describing actions taken during normal operation or incident conditions and documenting the system assessment (including upgrade and improvement), monitoring and communication plans and supporting programmes.

The WSP will guide both day to day actions and long term planning. It will identify crucial aspects that collectively ensure the provision of safe water and aid system managers and operators in gaining a better understanding of the water supply system and the risks that need to be managed (WHO2). Some of these aspects include: regular monitoring and inspections that signal deteriorating water quality (and prompt action) regular on-going maintenance to reduce the chance of failure by contamination guidance for improvement and expenditure additional training and capacity building initiatives a list of where to get help, who needs to know details of water quality, and how quickly they

need to know A diagram of the steps involved in conducting an assessment based on the WSP approach is presented in Figure 2.

Figure 2: Steps used to guide an assessment of water supply based on the WSP approach

This document is a guideline that focuses on the methodology that can be used to develop a water safety plan for small community water supply in South Africa. A comprehensive checklist has also been included to ensure the proper development and maintenance of a Water Safety Plan.

STEP ONE STEP TWO STEP THREE

Risk Management

Control measures applied.

Operational monitoring.

Management procedures (corrective actions and incident/emergency response).

Supporting programmes.

Record keeping and documentation.

Validation and verification.

Water supply system assessment

Team assembled to conduct WSP.

Intended use of water established.

Risk assessment Hazard identification

(biological., chemical., physical or radiological) from source to consumer.

Hazardous event identification.

Risk of hazard causing harm to population.

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SECTION 2: METHODOLOGY ON HOW TO DEVELOP A WATER SAFETY PLAN

The World Health Organisation (WHO2) has outlined steps on how to conduct the WSP. This section incorporates these basic principles as well as additional information obtained during a literature review of various other WSPs that have already been established in other countries. 2.1 ASSEMBLE A TEAM TO CARRY OUT THE WATER SAFETY PLAN The institutional framework for the provision of potable water in South Africa is outlined below. A collaborative multi-stakeholder approach is required as it will ensure that all the agencies with responsibility for specific areas within the water cycle are involved in the management of water quality.

National government (DWAF*, DoH**, DoE***)

Provincial government

Local government

(Water Service Providers, Water Service Authorities including local and district municipalities)

Water users

(Commercial and private users)

* Department of Water Affairs and Forestry ** Department of Health *** Department of Education

Figure 3: Institutional framework for the provision of potable water in South Africa A multidisciplinary team of experts with a thorough understanding of the drinking water system is assembled. These individuals are involved in each stage of the drinking water supply and include: engineers catchment and water managers water quality specialists environmental., public health or hygiene professionals operational staff of treatment plants consumer representatives A senior member of the team is appointed to help guide and direct the team through the preparation of the water safety plan and the assessment of the system. The team leader must have the authority, organizational skills and interpersonal skills to ensure that the project can be implemented. The team’s responsibility is to define the scope of the water safety plan that will include which part of the water supply chain is involved and the general classes of hazards to be addressed. The size of the team will vary between the different types of water suppliers and in some instances it may be useful to identify sub-teams to take lead in specific activities. Operational staff involvement is essential as they often have the greatest knowledge about problems in the supply system. In situations where the required skills are unavailable locally, the team leader should seek external support.

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2.2 DOCUMENT AND DESCRIBE THE SYSTEM A complete understanding of the system including the range and magnitude of hazards that may be present and the ability of existing processes and infrastructure to manage actual or potential risks is essential. In order to accomplish this successfully, it is necessary to document and describe the system. During this process, various factors for each step in the water supply system must be considered. These factors are listed in Table 1. Table 1: Factors for consideration during the documentation and description of the system

Source water and catchment Treatment Distribution system Capacity of the source in relation to demand Protection measures applied Developments in the catchments that affect quality Known water quality problems

Processes applied Number of individual units Age of plant Known design faults

Number of service reservoirs Volume of these reservoirs Age of reservoir Known design faults Area/s of distribution and population served Known operational problems

Source: Godfrey and Howard, 2004 The next stage is to define the intended use of water, i.e. will the water be used for domestic, industrial or agricultural use. It will also address the susceptibility of the end users and attempt to identify particularly vulnerable sub-groups that may be at particular risk. The description of the intended use of water should also include (Godfrey and Howard, 2004): The numbers of people served. Socio-economic status of people served. Intended use of water and the relevant exposure routes. Consumer education available for water use and how this is communicated, including how

consumers are notified of potential contamination. Special considerations are required for vulnerable groups such as infant, elderly and immuno-

compromised. 2.3 ASSESS THE EXISTING PROPOSED SYSTEM (INCLUDING A

DESCRIPTION OF THE PROCESS AND A FLOW DIAGRAM) A flow diagram of the water supply system must be constructed. It will provide an overview description of the drinking water system and will enable hazards to be identified clearly. The flow diagram will contain: Characterization of the source. Identification of potential pollution sources in the catchment. Measures of resource and source protection. Treatment processes. Storage and distribution infrastructure. A symbol chart for each step of the water supply system has been designed to provide consistency when drawing the flow diagram. These are given below (Figure 4) with an example of how a flow diagram should be drawn (Figure 5). It is important to ensure that the representation of the drinking water system is conceptually accurate as it is possible to overlook potential hazards that may be significant. In order to achieve this, confirmation of the flow diagram is required. If the flow diagram is inaccurate the team will not consider appropriate control measures for any hazards that were overlooked. A common method of validating a flow diagram is to pay a visit to the system and confirm the set up of the system and processes. Validation of the flow diagram is also beneficial in determining the vulnerability of the system in terms of its design and construction (refers to aspects that are

7

unlikely to change unless a rehabilitation programme is initiated) and the operation and maintenance of the system (those changes that are likely to occur rapidly and unpredictably). Proof of the flow chart validation must be signed and dated by a team member and documented thereafter.

Water source Ground □ Surface ⊠

Raw water storage reservoir

Open ◫ Closed ⊟

Pre-treatment Fluoride, iron and manganese, taste and odour removal., disinfection, etc. ⊞

Main treatment processes

Coagulation ⊘ Flocculation ⊗

Sedimentation ⊖ Filtration ⊕

pH adjustment Lime, CO2, soda ash

Disinfection

Chlorine gas, Cl2, chloramination, ozone, UV, HTH ◬

Distribution

On site service reservoir/s ▧ Off site service reservoir/s ▨

Booster stations ⊡ Valves ⋈

Consumer

Pipes (urban/semi-urban) ⊜ Stand pipes and house connections ⌂

Figure 4: Symbol chart for drawing flow diagrams of water treatment systems

⊠ Surface water from catchment (upstream)

↓

⊞ Pre-treatment (disinfection Cl2 and UV)

↓

◫ Downstream harvesting storage

↓

◬ pH adjustment, disinfection (lime, Cl2 gas)

↓

⊜ Urban pipes

▨ ▨ Closed service reservoirs

↓

⊡ Booster station

(2o chloramination) ↓ ⌂ ⌂

House connections

Figure 5: An example of a flow diagram for a system

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2.4 UNDERTAKE A HAZARD ASSESSMENT AND A RISK CHARACTERIZATION TO IDENTIFY AND UNDERSTAND HOW HAZARDS CAN ENTER INTO THE WATER SUPPLY

2.4.1 Identifying Hazards A hazard is any agent that will cause an adverse health effect if it is consumed via drinking water. A hazardous event is an incident or situation that can lead to the presence of a hazard. Hazards may be microbiological, physical or chemical in origin. Identification of hazards is important to ensure that adequate protection measures can be applied and to identify treatment requirements. At each step the intention is to determine what could happen that could lead to contamination, and the associated control measures for each hazard. Once hazard/s have been identified, consideration of the events that lead to their entry into the drinking water supply system is required. An easier way of developing an understanding of hazards is to determine the possible sources rather than trying to mark out specific hazards. Sources of potential hazards or hazardous events can be found in each step of the water supply system. These are listed in Table 2. The impact of the hazard can be characterised by assessing the severity of the likely health outcome (in terms of the impact and population affected) and the probability of occurrence. 2.4.2 Prioritizing Hazards A risk is the likelihood of the identified hazard/s causing harm to exposed populations in a specified timeframe including the magnitude of that harm and/or the consequences. In any system there may be a number of hazards (Table 2) and a large number of control measures. It is therefore important to rank hazards in order to establish priorities. The hazard assessment matrix in Table 3 (WHO2) is a guide to scoring the existing risks that could make water unsafe. Likelihood is determined by “how often’ or “how likely” a hazard or a hazardous event occurs. It must take into account hazards that have occurred in the past and their likelihood of re-occurrence and must also predict the likelihood of hazards and events that have not occurred to date. Consequence determines the severity of the results of the hazard/hazardous event and the seriousness or intensity of the impact of the hazard to human health.

RISK RATING = LIKELIHOOD CONSEQUENCE Multiplying the derived likelihood ratings with derived consequence ratings from the risk assessment matrix produces a risk rating. E.g. a likelihood rating of 0.8 multiplied by a consequence rating of 70 would give a risk rating of 0.8 70 = 56, which would be ranked higher than an event with a likelihood of 0.2 and a consequence of 2 and a risk rating of 0.2 2 = 0.4. A higher score implies that a bigger risk of a hazardous event occurring exists and should therefore be prioritised. A risk profile based on the calculated score is given in Table 4.

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Table 2: Sources of potential hazards or hazardous events in the water supply system

ELEMENTS OR PROCESSES OF A DRINKING WATER

SYSTEM

POTENTIAL HAZARDS OR HAZARDOUS EVENTS

Source Water: Surface

On-site septic tank systems Domestic waste dumping Land spreading of manure Feedlot runoff Municipal sewage effluent Heavy metal., pharmaceutical residuals Municipal landfills Industrial activities Leaking pipelines Pesticide use Petroleum refineries Highway, railway accidents and spills Recreational activities Natural events – flooding, droughts, etc.

Source Water: Ground

On-site septic systems Domestic waste dumping Municipal landfills Graveyards Land spreading of manure Intensive livestock activities Gas service stations – hydrocarbon contamination Industrial plants Leaking pipelines – hydrocarbon contamination Sludge disposal areas and petrol refineries Highway/railway accidents and spills

Treatment systems

Water optimization – failure Coagulant dosing – failure Filtration – failure Coagulation, flocculation and sedimentation – biofilm growth Inlet flow control – failure pH correction – inappropriate levels Disinfection – under/over dose Reservoir storage – contamination

Distribution

Reservoirs – security control failure Pump stations – security control failure Distribution transmission mains – geological faults Distribution water mains – geological faults Re-chlorination points – under or over dosage Main breaks – contamination of mains Cross section with sewage pipes (microbial hazard)

Other water delivery systems

Tank truck storage – loss of sterile conditions Tank truck previous use – contamination Cisterns – contamination

Source: CWWA, 2005

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Table 3: Risk Assessment Matrix

LIKELIHOOD RATING CONSEQUENCE RATING Almost certain

(once a day or permanent feature) 1

Catastrophic (Death expected from exposure)

100

Likely (once per week)

0.8 Major

(Population exposed to significant illness)

70

Moderately likely (once per month)

0.5 Moderate

(Large aesthetic impact) 20

Unlikely (once per year)

0.2 Minor

(Small aesthetic impact) 2

Rare (1 in 5 years)

0.1 Insignificant (No impact)

1

Table 4: Risk profile based on score calculated from risk assessment matrix

SCORE RISK PROFILE

0-10 Low

These are systems that operate with minor deficiencies. Usually the systems meet the water quality parameters specified by the appropriate guidelines (SANS 241:2006).

11-56

Medium These are systems with deficiencies which individually or combined pose a high risk to the quality of water and human health. These systems would not generally require immediate

action but the deficiencies could be more easily corrected to avoid future problems.

57-100

High These are systems with major deficiencies which individually combined pose a high risk to the quality of water and may lead to potential health and safety or environmental concerns. Once systems are classified under this category, immediate corrective action is required to

minimizeor eliminate deficiencies. 2.5 IDENTIFY CONTROL MEASURES – THE MEANS BY WHICH RISKS CAN

BE CONTROLLED 2.5.1 Identifying Control Measures Control measures are actions that reduce levels of hazards within water supply systems either by preventing entry, reducing concentration, or by restricting their production. Many control measures are effective against more than one specific hazard while some hazards may require more than one control measure for effective control. The assessment and planning of control measures should ensure that health-based targets will be met and should be based on hazard identification and assessment. Identification and implementation of control measures needs to be based on a multi-barrier principle so that if one barrier fails, the remaining barriers will still operate, thus minimizing the likelihood of contaminants passing through the entire system and being in sufficient amounts to cause harm to consumers. Some control measures are actions at specific points in the system and are referred to as control points. Defining control points is an important component of the water safety plan and provides water utilities with information regarding where specific actions need to be taken to ensure water safety. Control points should not be the only focus of water utilities to ensure water supply as a collective and preventative approach is required.

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The prioritization of control measures and points must be related to the severity of the potential risk. Control points identified as being of higher priority are therefore monitored more frequently to ensure that there is compliance. For each control measure, critical limits should be defined. Critical limits are the performance targets that, when exceeded, compromise the quality of water being supplied. Critical limits define when the control measure is out of compliance and action is required. It is essential that critical limits be directly or indirectly measurable. SANS 241 provides critical limits for various constituents in the water matrix. Limits will be indicators that can be readily interpreted at the time of monitoring and where actions can be taken in response to non-compliance. Critical limits are defined so that they do not automatically lead to a breakthrough of pathogens into the water supply, but signal that actions are required urgently to prevent an unacceptable level of risk occurring. Control measures should be identified for each step in the water supply. Some important factors that need to be considered are listed in Table 5 (WHO2).

12

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atm

ent

proc

ess

optim

izat

ion

incl

udin

g:

chem

ical

do

sing

, fil

ter

back

was

hing

, flo

w

rate

, m

inor

in

fras

truc

ture

m

odifi

catio

ns

U

se

of

tank

st

orag

e in

pe

riods

of h

eav

y ra

infa

ll

D

istr

ibut

ion

syst

em

mai

nten

ance

Ava

ilabi

lity

of b

ack-

up

syst

ems

M

aint

aini

ng a

n ad

equ

ate

disi

nfec

tant

res

idua

l co

ncen

trat

ion

C

ross

con

nect

ion

and

back

-flo

w p

reve

ntio

n de

vice

s im

plem

ente

d

F

ully

enc

lose

d di

strib

utio

n sy

stem

s an

d st

orag

e fa

cilit

ies

A

ppro

pria

te r

epai

r pr

oced

ure

s in

clud

ing

subs

eque

nt d

isin

fect

ion

of

wat

er m

ains

Mai

ntai

ning

ade

qua

te

syst

em p

ress

ure

Sou

rce:

WH

O2

13

2.5.2 Defining Corrective Actions for Each Control Measure For each control measure, corrective actions should be determined and adhered to as soon as critical limits have been exceeded. This is an important component of the management aspects of the Water Safety Plan and should be effective in restoring performance to acceptable levels when critical limits are exceeded. Corrective actions may include a wide range of actions, e.g. the ability to change temporarily to an alternate water source, the use of back-up disinfection plants or spot dosing. Corrective actions must be supported by a contingency plan. This plan is a detailed management response to failures and will identify individual responsibilities and a time constraint for remedy. Corrective actions should also include long term actions designed to prevent non-compliance and reduce the need for contingency plans to be re-actioned. This may require defining/identifying new control measures and will be linked to on-going investment plans. A range of suggested corrective actions (NMHRC, 2005) for various hazards has been included in Annexure B. 2.6 DEFINE MONITORING OF CONTROL MEASURES – WHAT LIMITS

DEFINE ACCEPTABLE PERFORMANCE AND HOW THESE ARE MONITORED

Monitoring is the act of conducting a planned series of observations or measurements of operational and/or critical limits to assess whether the components of the water supply are operating properly. The objectives of operational monitoring are for the drinking water supplier to monitor each control measure in a timely manner to enable effective system management and to ensure that health-based targets are achieved. The parameters selected for operational monitoring should: reflect the effectiveness of each control measure provide a timely indication of performance be readily measured provide opportunity for an appropriate response Control measures should be closely monitored, especially in the early stages of the WSP, in order to ensure that any problems that have been identified are rectified timeously. The strategies and procedures for monitoring the various aspects of the water supply system should be documented. Monitoring plans should include the following: Parameters to be monitored. Sampling location and frequency. Sampling needs and equipment. Schedules for sampling. Methods for quality assurance and validation of sampling results. Responsibilities and necessary qualifications of staff. Requirements for documentation and management of records including how monitoring of

results will be recorded and stored. Requirements for reporting and communication of results. Frequency of operational monitoring is generally dependent on population size. Table 6 lists the suggested sampling types and frequencies based on population served (SANS 241:2006).

14

Table 6: Suggested sampling types and frequencies based on population served

POPULATION SERVED 0-

2500 2501-10000

10001-25000

25001-100000

>100001

FREQUENCY (NUMBER OF SAMPLES PER YEAR)

12 24 36 120 120 every year per

100000 of population served

Physical and organoleptic requirements Colour 1 1 4 12 12 Conductivity at 25°C 12 24 36 120 365 Dissolved solids 1 1 4 12 12 Odour 12 24 36 120 365 pH value at 25°C 12 24 36 120 365 Taste 12 24 36 120 365 Turbidity 12 24 36 120 365 Chemical determinands Ammonia as N 1 1 4 12 12 Calcium as Ca 1 1 4 12 12 Chloride as Cl 1 1 4 12 12 Fluoride as F 1 1 4 12 12 Magnesium as Mg 1 1 4 12 12 Nitrate and nitrite as N 1 1 4 12 12 Potassium as K 1 1 4 12 12 Sodium as Na 1 1 4 12 12 Sulphate as SO4 1 1 4 12 12 Zinc as Zn 1 1 1 4 4 Aluminium as Al 1 1 4 12 12 Antimony as Sb 1 1 1 4 4 Arsenic as As 1 1 1 4 4 Cadmium as Cd 1 1 1 4 4 Chromium as Cr 1 1 1 4 4 Cobalt as Co 1 1 1 4 4 Copper as Cu 1 1 1 4 4 Cyanide (recoverable) as CN

1 1 1 4 4

Iron as Fe 1 1 4 12 12 Lead as Pb 1 1 1 4 4 Manganese as Mn 1 1 4 12 12 Mercury as Hg 1 1 1 4 4 Nickel as Ni 1 1 1 4 4 Selenium as Se 1 1 1 4 4 Vanadium as V 1 1 1 4 4 Organic determinands Dissolved organic carbon as C

1 1 1 4 4

Total trihalomethanes 1 4 4 12 12 Phenols 1 1 1 4 4 Microbiological determinands E. coli 12 24 36 120 365 Permanent records of the results of monitoring and documented monitoring plans should be maintained. If monitoring shows that a critical limit has been exceeded, the potential for water to be unsafe is increased and requires that immediate action be taken.

15

2.7 ESTABLISH PROCEDURES TO VERIFY THAT THE WATER SAFETY PLAN IS WORKING EFFECTIVELY AND WILL MEET THE HEALTH-BASED TARGETS

Verification, in addition to operational monitoring of the performance of the individual components of a drinking water system, is necessary to ensure that the system as a whole is operating safely. Verification may be undertaken by the Water Service Provider, the Water Service Authority, an independent authority or by a combination of these. Verification provides a mechanism by which the water supplier and surveillance body are able to check whether the system is delivering water that meets safety requirements. Verifying performance requires assessment of a range of performance indicators. Verification will involve both operational audit and water quality analyses using a range of index organisms. Operational audit should include the systematic review of operational procedures and documentation to ensure that the WSP is working. During the audit, operational records of all treatment processes and distribution system maintenance should be reviewed to assess whether they exhibit the requirements for each component of the system. In addition, spot checks in the field should be carried out. A key element of the audit process is to identify when monitoring results show deviation from critical limits and what operational shortcomings may have been the cause. The audit should identify shortcomings in the overall WSP and identify modifications and improvements required for the WSP. 2.8 DEVELOP SUPPORTING PROGRAMMES Many actions are important in ensuring drinking water safety but do not directly affect drinking water quality and are therefore not control measures. These are referred to as supporting programmes and should be documented in a WSP. Supporting programmes are activities that ensure the operating environment, equipment used and the people themselves do not become an additional source of potential hazards to the drinking water supply. Supporting programmes could specifically involve: Control and access of people onto treatment plants, catchments and reservoirs and

implementation of the appropriate security measures to prevent transfer of hazards from people when they do enter source water.

Development of verification protocols for the use of chemicals and materials used in water supply (for suppliers to partake in international quality assurance programmes).

Designated equipment for attending to incidents (e.g. main bursts) and equipment used for sewage water should not be used for potable water.

Training and educational programmes for personnel involved in activities that could influence water safety. Training should be implemented as part of induction programmes and frequently updated.

Codes of good operating, management and hygienic practice are essential elements of supporting programmes. These are often captured within standard operating procedures (SOPs) and include: Hygienic working practices documented in maintenance SOPs. Training and competence of personnel involved in water supply. Tools for managing the actions of staff such as quality assurance systems. Securing stakeholder commitment at all levels to the provision of safe water. Education of communities whose activities influence water quality. Calibration and monitoring of equipment. Record keeping.

16

Comparison of supporting programmes with those of others through peer review, benchmarking and personnel or document exchange can encourage ideas for improved practice. 2.9 PREPARE MANAGEMENT PROCEDURES Effective management involves actions to be taken in response to variations that occur during “normal” operating conditions and “incident” situations where the loss of a control system may occur, and of procedures to follow in unforeseen and emergency situations. Management plans should be documented alongside system assessment, monitoring plans, supporting programmes and communication required to ensure safe operating of the system. Emergency response plans should clearly specify responsibilities for co-ordinating measures to be taken, a communication plan to inform/alert users of supply and plans for providing/distributing emergency supplies of water. Key areas to be addressed in emergency response plans include: Response actions – including increased monitoring. Plans for emergency water supplies. Responsibilities and authorities internal and external to the organization. Communication strategies and protocols including notification procedures (internal, regulatory

body, media, public). Mechanisms for increased public health surveillance. The DWAF DWQ Framework (2007) has identified alert levels based on the public health risk and aesthetic quality to respond to acute drinking water failure. Three Alert Levels are proposed to respond to acute drinking water quality failures: Alert Level I (Drinking Water Incident – no significant risk to health): Routine problems

including minor disruptions to the water system and single sample non-compliances. Alert Level II (Drinking Water Failure – potential minor risk to health): Minor emergencies,

requiring additional sampling, process optimisation and reporting/ communication of the problem.

Alert Level III (Drinking Water Emergency – potential major risk to health): Major emergencies requiring significant interventions to minimizepublic health risk (Engagement of a designated Emergency Management Team).

Tables 7 and 8 below indicate the classification of Alert Level concentrations for both health related and aesthetic variables and the required actions.

17

Tab

le 7

: In

cid

ent

Man

agem

ent

Pro

toco

l fo

r H

ealt

h R

elat

ed D

rin

kin

g W

ater

Qu

alit

y In

cid

ents

Cla

ssif

ic-

atio

n o

f In

cid

ent

Wat

er Q

ual

ity

Co

nst

itu

ent

and

Co

nce

ntr

atio

n

Hea

lth

imp

licat

ion

/ris

k In

cid

ent

Man

age-

men

t

Req

uir

edR

esp

on

se

Tim

e A

cti

on

Ale

rt L

eve

l I

(Drin

king

W

ater

Q

ualit

y In

cide

nt)

1

E. c

oli p

er 1

00

mL

1

Col

iph

age

per

10 m

L

A

ny

hea

lth-r

ela

ted

phys

ical

or

che

mic

al r

esul

t tha

t ex

cee

ds th

e up

per

limit

of

SA

NS

241

: 20

06 D

rink

ing

Wat

er C

lass

I lim

it

In

sign

ifica

nt c

han

ce o

f inf

ectio

n.

V

ery

slig

ht r

isk

of v

iral i

nfec

tion

with

con

tinu

ous

expo

sure

.

Insi

gnifi

cant

ris

k to

hea

lth –

su

itab

le fo

r lif

etim

e co

nsum

ptio

n.

Inte

rnal

Within 24 hrs of result release

C

omm

unic

ate

out-

of-r

ange

res

ult t

o re

leva

nt m

unic

ipa

l st

aff;

A

sses

s as

soci

ated

info

rmat

ion

and

impl

eme

nt c

orre

ctiv

e ac

tion

to r

ectif

y th

e in

cid

ent o

r re

sam

ple

to c

onfir

m r

esul

t if

requ

ired;

If re

sam

ple

resu

lt co

nfirm

s th

e in

itial

res

ult,

impl

eme

nt

corr

ectiv

e ac

tion

to r

ectif

y th

e in

cid

ent;

If

resa

mpl

e re

sult

exc

eeds

the

con

cent

ratio

ns s

peci

fied

in

Ale

rt L

eve

l I, p

roce

ed

to A

lert

Lev

el I

I.

Ale

rt L

evel

II

(Drin

king

W

ater

Q

ualit

y F

ailu

re)

2-

10 E

. col

i per

100

mL

2-10

Col

iph

age

s pe

r 10

mL

1 C

rypt

ospo

ridiu

m o

r G

iard

ia c

yst p

er

10 L

Tur

bidi

ty r

esul

t >

5 N

TU

Flu

orid

e re

sult

0.9-

1.7

mg/

L

C

linic

al in

fect

ions

unl

ikel

y in

he

alth

y ad

ults

, but

ma

y oc

cur

in

sens

itive

gro

up

s.

Lo

w r

isk

of v

iral i

nfec

tion

with

co

ntin

uous

exp

osur

e.

Lo

w r

isk

of p

roto

zoa

n pa

rasi

te

infe

ctio

n.

In

dire

ct a

ssoc

iate

d im

pac

ts o

n he

alth

thro

ugh

the

shi

eld

ing

of

bact

eria

from

dis

infe

ctio

n.

S

light

mot

tling

of d

enta

l ena

mel

.

Inte

rnal

an

d E

xter

nal

Same day as result release

R

eque

st a

ddi

tiona

l mon

itori

ng

as r

equ

ired

(bot

h sp

atia

lly

and

incr

ease

d fr

eque

ncy)

to e

stab

lish

the

sour

ce o

f the

co

ntam

inat

ion

and

the

risk

to p

ublic

he

alth

;

Ass

ess

trea

tmen

t pro

cess

effi

cien

cy a

nd im

ple

me

nt

corr

ectiv

e ac

tion

to o

ptiim

izet

he

trea

tmen

t pro

cess

;

Com

mun

icat

e th

e dr

inki

ng

wat

er fa

ilure

an

d h

ealth

ris

k to

th

e re

leva

nt m

unic

ipa

l sta

ff, D

WA

F a

nd D

oH;

If

any

addi

tiona

l sam

ple

resu

lts e

xcee

d co

ncen

trat

ions

sp

ecifi

ed in

Ale

rt L

evel

II,

proc

eed

to A

lert

Lev

el I

II.

18

Cla

ssif

ic-

atio

n o

f In

cid

ent

Wat

er Q

ual

ity

Co

nst

itu

ent

and

Co

nce

ntr

atio

n

Hea

lth

imp

licat

ion

/ris

k In

cid

ent

Man

age-

men

t

Req

uir

edR

esp

on

se

Tim

e A

cti

on

Ale

rt L

evel

III

(Drin

king

W

ater

Q

ualit

y E

mer

genc

y)

>

10 E

. col

i per

100

mL

>10

Col

iph

age

s pe

r 10

mL

>1

Cry

ptos

porid

ium

or

Gia

rdia

/10

L

A

ny

hea

lth-r

ela

ted

Ph

ysic

al

or C

hem

ical

re

sult

that

ex

cee

ds th

e up

per

limit

of

SA

NS

241

: 20

06 D

rink

ing

Wat

er C

lass

II li

mit

(with

in

exce

ptio

n of

turb

idity

)

Flu

orid

e re

sult

>1.

7 m

g/L

C

linic

al in

fect

ions

com

mon

, eve

n w

ith o

nce-

off c

onsu

mpt

ion.

Sig

nifi

cant

and

incr

easi

ng r

isk

of

infe

ctio

us d

ise

ase

tran

smis

sion

.

Sig

nifi

cant

ris

k of

pro

tozo

an

para

site

infe

ctio

n.

S

ign

ifica

nt r

isk

to h

uman

hea

lth

–ma

xim

um a

llow

abl

e lim

its

exce

ede

d.

S

ever

e to

oth

dam

age

and

skel

eta

l flu

oros

is w

ith lo

ng-t

erm

ex

posu

re.

Inte

rnal

an

d E

xter

nal

Immediate

E

nga

ge E

mer

gen

cy M

anag

em

ent T

eam

;

Com

mun

icat

e dr

inki

ng w

ater

em

erg

ency

an

d he

alth

ris

k to

re

leva

nt m

unic

ipal

sta

ff, D

G o

f DW

AF

, hea

d of

pro

vinc

ial

DoH

;

Con

tinue

add

ition

al m

onito

rin

g an

d e

xten

d to

the

dist

ribut

ion

syst

em a

nd p

oin

t-of

-use

to e

stab

lish

the

sour

ce

and

ext

ent

of t

he in

cide

nt a

nd th

e ris

k to

pub

lic h

ealth

;

Ass

ess

the

com

mun

ities

at r

isk

and

the

nee

d fo

r an

al

tern

ate

wat

er s

uppl

y;

C

omm

unic

ate

drin

king

wat

er e

mer

gen

cy to

com

mun

ity;

Im

plem

ent

spe

cial

ist p

roce

ss a

sses

sme

nt a

nd

optim

isat

ion

of th

e dr

inki

ng w

ater

sup

ply

syst

em fr

om c

atch

men

t to

cons

umer

;

Pha

se o

ut a

dditi

ona

l mon

itori

ng

once

the

sou

rce

of th

e in

cid

ent h

as b

een

iden

tifie

d an

d re

ctifi

ed a

nd t

wo

cons

ecut

ive

resu

lts h

ave

bee

n w

ithin

spe

cific

atio

n;

P

repa

re n

otifi

catio

ns a

dvis

ing

of t

he e

nd o

f the

em

erge

ncy;

Ass

ess

requ

ired

prev

ent

ativ

e ac

tion

to r

educ

e th

e lik

elih

ood

of th

e in

cide

nt r

ecu

rrin

g;

P

repa

re a

rep

ort

to d

ocum

ent a

nd c

lose

the

inci

den

t;

Rev

iew

an

d up

date

Inci

den

t M

ana

gem

ent

Pro

toco

l;

Ret

rain

sta

ff on

rev

ised

Inci

dent

Man

agem

en

t Pro

toco

l. In

the

case

of a

fluo

ride

ove

rdos

e in

exc

ess

of 1

0 m

g/L,

the

Dire

ctor

-Ge

ner

al o

f the

De

par

tmen

t of H

ealth

is a

lso

requ

ired

to b

e in

form

ed

(Sch

edul

e of

Reg

ula

tions

on

Flu

orid

atin

g W

ater

Sup

plie

s u

nder

Nat

ion

al H

ealth

Act

(N

o. 6

1 of

200

3)).

19

Tab

le 8

: In

cid

ent

Man

agem

ent

Pro

toco

l fo

r A

esth

etic

Dri

nki

ng

Wat

er Q

ual

ity

Inci

den

ts

Cla

ssif

ic-

atio

n o

f In

cid

ent

Wat

er Q

ual

ity

Co

nst

itu

ent

and

C

on

cen

trat

ion

A

es

thet

ic im

plic

atio

n/r

isk

Inci

den

t M

anag

e-m

ent

Req

uir

edR

esp

on

se

Tim

e A

cti

on

Ale

rt L

eve

l I

(Inc

iden

t)

G

eosm

in o

r 2-

MIB

5-

10 n

g/L

Iron

0.2

-1.0

mg

/L

M

ang

anes

e 0.

1-0.

4 m

g/L

M

oder

ate

unpl

easa

nt

tast

es/o

dour

s.

S

light

tast

e an

d co

lour

, slig

ht

stai

ning

of

whi

te c

loth

es

S

light

tast

e an

d co

lour

, mod

era

te

stai

ning

of c

loth

es a

nd

fixtu

res

Internal

Within 24 hrs of result release

C

omm

unic

ate

out-

of-r

ange

res

ult

to r

elev

ant

mun

icip

al s

taff;

Ass

ess

asso

ciat

ed in

form

atio

n an

d im

plem

ent

cor

rect

ive

actio

n to

rec

tify

the

inci

den

t or

resa

mpl

e to

con

firm

res

ult

if re

quire

d;

If

resa

mpl

e re

sult

conf

irms

the

initi

al r

esul

t, im

plem

ent

co

rrec

tive

actio

n to

rec

tify

the

inci

den

t;

If re

sam

ple

resu

lt e

xcee

ds th

e c

once

ntra

tions

spe

cifie

d in

A

lert

Lev

el I

, pro

cee

d to

Ale

rt L

eve

l II.

A

lert

Lev

el I

I (F

ailu

re)

G

eosm

in o

r 2-

MIB

11-

20 n

g/L

Iron

1.1

-2.0

mg

/L

M

ang

anes

e 0.

5-1.

0 m

g/L

M

oder

ate

unpl

easa

nt

tast

es/o

dour

s

Mod

erat

e ta

ste

and

col

our,

m

oder

ate

stai

nin

g of

wh

ite c

loth

es

M

oder

ate

tast

e a

nd c

olou

r,

incr

eas

ing

stai

nin

g of

clo

thes

and

fix

ture

s

Internal and External

Same day as result release

R

eque

st a

ddi

tiona

l mon

itori

ng

as r

equ

ired

(bot

h sp

atia

lly

and

incr

ease

d fr

eque

ncy)

to e

stab

lish

the

sour

ce o

f the

co

ntam

inat

ion

and

the

aest

hetic

impa

ct;

A

sses

s tr

eatm

ent p

roce

ss e

ffici

ency

and

imp

lem

ent

co

rrec

tive

actio

n to

opt

iimiz

eth

e tr

eatm

ent p

roce

ss;

C

omm

unic

ate

the

drin

kin

g w

ater

failu

re a

nd

aes

thet

ic

impa

ct t

o th

e re

leva

nt m

unic

ipal

sta

ff;

If

any

addi

tiona

l sam

ple

resu

lts e

xcee

d co

ncen

trat

ions

sp

ecifi

ed in

Ale

rt L

evel

II, p

roce

ed to

Ale

rt L

evel

III.

A

lert

Lev

el I

II (E

mer

genc

y)

G

eosm

in o

r 2-

MIB

>

20 n

g/L

Iron

>2

mg/

L

Man

gan

ese

>1

mg/

L

O

bjec

tiona

ble

and

incr

easi

ng

unp

leas

ant t

aste

s/od

our

s

Obj

ectio

nabl

e ta

ste

and

app

eara

nce,

sta

inin

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ste

and

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dditi

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ater

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om c

atch

men

t to

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umer

;

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se o

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once

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as b

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wo

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20

Following any emergency, an investigation should be undertaken and all individuals involved in the WSP should be updated and a discussion of the performance of the WSP and issues or concerns must be addressed. The investigation should consider factors such as: What was the initiating cause of the problem? How was the problem first identified or recognised? What were the most essential actions required? What communication problems arose and how they were addressed? What were the immediate and long term consequences? How well did the emergency response plan work? 2.10 ESTABLISH DOCUMENTATION AND COMMUNICATION PROCEDURES If document updates are prepared as information becomes available, it reduces the amount of updating required at the end of the year and will allow Water Service Authorities to receive more up-to-date progress reports for their own planning services. Documentation of a WSP includes: Description and assessment of drinking water system including programmes to upgrade

existing water delivery. A plan for operational monitoring and verification of drinking water system. Water and safety management procedures for normal operation and incident/ emergency

situations (including communication plans). Description of supporting programmes. Communication strategies should include: Procedures for promptly advising of any significant incidents within the drinking water supply

including notification of the public health authority. Summary information to be available to consumers, e.g. through the media, annual reports

and on the internet Establishment of mechanisms to receive and actively address community complaints in a

timely fashion.

2.11 REVIEW OF THE WSP The results of the verification exercise should be used to evaluate and review the water safety plan to see whether the field assessments identified need modifications. This requires analysis of the verification data to see if there are any deficiencies in the WSP. If verification shows that microbial contamination is detected despite the presence of control measures within their critical limits, this immediately indicates that control measures have been identified incorrectly, the critical limits are inappropriate or the control measures are insufficient. Internal or third party (independent) verification is recommended for the development of institutional relationships. During the review, the following questions should be addressed: How well is the WSP working? Were the necessary management plans undertaken adequate? If not, which areas require improvement to provide long-term sustainability of the WSP? The WSP should be reviewed: Annually. After an incident. After any significant change to the water supply. In response to finding a weakness in the plan. Additional information regarding the system is received that might warrant a revised risk level

for that system.

21

SECTION 3: CHECKLIST FOR CONDUCTING A WSP

Yes No

1 Has a multi-disciplinary team of experts been assembled to carry out the water safety plan?

2 Has the team been informed of their duties and commitment?

3 Has the water treatment system been described?

(i.e. has each step in the system been considered for range and magnitude of hazards that may be present, and the ability of existing processes and infrastructure to manage actual or potential risks)

4 Following the description of the system above, has all the information been documented?

5 Has a flow diagram of the entire water supply system been constructed using the symbol chart?

6 Have existing, as well as potential., hazards in the system been identified?

7 Have these hazards been prioritised using the hazard assessment matrix provided?

8 Are there any control measures in place to reduce/eliminate the hazards?

9 Is there a system in place to monitor the control measures?

10 Have corrective actions been identified for each control measure, especially if the control measure fails?

11 Are there procedures in place to verify that the WSP is working effectively and will meet the health-based targets?

12 Have supporting programmes been developed to ensure that health based targets will be met?

13 Have management procedures been prepared to respond to “normal” and “incident” conditions?

14 Has all the relevant information regarding the water supply system been documented?

(i.e. description and assessment of the system, plan for operational monitoring, plan for verification of drinking water system, management procedures, etc.)

15 Have communication procedures been established?

(i.e. general information on water quality through the media, annual reports and on the internet, procedures for promptly advising of any significant incidents, mechanisms to receive and actively address community complaints, etc.)

16 Has the WSP been reviewed at the following stages?

Annually

After an incident

After any significant change to the water supply

In response to finding a weakness in the plan

Additional information regarding the system is received that might warrant a revised risk level for that system

22

SECTION 4: REFERENCES A Framework on How to Prepare and Develop Public Health Risk Management Plans for Drinking Water Supplies, Ministry of Health, Wellington, New Zealand, June 2005. Blueprint for Safe Drinking Water, Small Treatment Drinking Water Supplies, Introduction to Risk Management Planning, Ministry of Health, Wellington, New Zealand, June 2005. Canadian Guidance Document for Managing Drinking Water Systems: A Risk Assessment / Risk Management Approach, Prepared for Health Canada by: Canadian Water and Wastewater Association (CWWA), September, 2005. Chapman and Hall, Water Quality Assessments: A guide to the use of biota, sediments and water in environmental monitoring, First edition, 1992. Department of Water Affairs and Forestry: Drinking Water Quality Framework for South Africa, Edition 2, May 2007. Department of Water Affairs and Forestry, Department of Health, Water Research Commission; Quality of Domestic Water Supplies, Volume 1: Assessment Guide, Second Edition, 1998. Hendricks Lindiwe, Minister of Water Affairs and Forestry, Budget Vote Speech, May 2008 Howard G, Water safety plans for small systems: a model for applying HACCP concepts for cost-effective monitoring in developing countries, Water Science and Technology. 47(3):215-20, 2003. Improving the Efficiency of Disinfection in Small Drinking Water treatment Plants, K5/1531, Water Research Commission (SA), 2007. International Water Association (IWA), The Bonn Charter for safe drinking water, September 2004. NHMRC Rural and Remote Drinking Water Quality Management Modules, National Health and Medical Research Council Australia, Version 4, August 2005. Risk Assessment for Private Water Supplies, Section Four, Private Water Supplies (Government Organization), United Kingdom. Sam Godfrey, Guy Howard, Water safety plans for utilities in Developing countries, A case study from Kampala Uganda, Water, Engineering and Development Centre, Loughborough University, Leicestershire, United Kingdom, 2002. Sam Godfrey and Guy Howard, Water Safety Plans (WSP) for Urban Piped Water Supplies in Developing Countries, Water, Engineering and Development Centre, Loughborough University, Leicestershire, United Kingdom, 2004. Small Community Water Supply Management; WHO, Samorka, Orkuveita Reykjavikur; Reykjavik, Iceland, January 2005. Small Drinking Water Supplies – Preparing a Public Health Risk Management Plan, Ministry of Health, Wellington, New Zealand, June 2005. Techneau WP 4.2, Foundations for a framework for integrated risk assessment and methods for risk analysis Draft, March 2006. WHO1, Guidelines for drinking water quality, Chapter 2 – The guidelines: a framework for safe drinking water, 2004.

23

WHO2, Water Safety Plans – Managing drinking-water quality from catchment to consumer, World Health Organization, Geneva, 2005.

24

ANNEXURE A: RISK ASSESSMENT FORM

SECTION A: DESCRIPTION OF WATERWORKS

ITEM 1 Name of Waterworks

Ownership

Municipal DWAF Other Government

Private Farm Park Other (Specify)

Locality Urban Peri-urban Rural

Province Year of Construction Person in Charge of the Waterworks

Postal Address

Postal Code Telephone Fax E-mail (if any) GPS-Global Positioning System co-ordinates

ITEM 2

Diagram of the supply Provide a flow diagram showing the inter-relationships and various components of the supply source, treatment process and distribution system from the catchment to the consumer. The diagram should include: immediate catchment wider catchment collection point/s treatment processes used and major distribution pipe work (i.e. pumps, storage systems, pipelines)

Refer to the symbol chart and example of a flow diagram (Figures 4 and 5) before proceeding with a diagram of your own system. ITEM 3 In the sections that follow, an evaluation of the system is conducted in order to determine if any hazards exist or if any hazardous events are likely to occur. The hazard assessment matrix shown in Table 3 (page 10) is a guide to scoring the existing risks that could make water unsafe (i.e. cause a deterioration in water quality) and should be referred to throughout the evaluation.

Likelihood is determined by “how often’ or “how likely” a hazard or a hazardous event occurs. It should take into account hazards that have occurred in the past and their likelihood of re-occurrence and should also predict the likelihood of hazards and events that have not occurred to date.

25

Consequence looks at the severity of the results of the hazard/hazardous event and the seriousness or intensity of the impact of the hazard. When dealing with impact we are concerned with human health only.

RISK RATING = LIKELIHOOD CONSEQUENCE

Multiplying the derived likelihood ratings with derived consequence ratings from the risk assessment matrix produces a risk rating. e.g. a likelihood rating of 0.8 multiplied by a consequence rating of 70 would give a risk rating of 0.8 70 = 56, which would be ranked higher than an event with a likelihood of 0.2 and a consequence of 2 and a risk rating of 0.2 2 = 0.4. A higher score implies that a bigger risk of a hazardous event occurring exists and should therefore be prioritised. A risk profile is given below: Risk Profile: LOW – 0-10 MEDIUM – 11-56 HIGH – 57-100

SECTION B: EVALUATION OF CATCHMENT AND RAW WATER SOURCE

Name of Catchment

Name of Raw Water Supply Source

Location of the Source

(Mark with a cross where applicable)

What Source of Water Is Used?

Dam River/Stream Spring Borehole Wells Other (Specify)

Person in charge of the Supply

Postal Address

Postal code Telephone Fax E-mail GPS-Global Positioning System co-ordinates

(Mark with a cross where applicable)

26

Is The Water Source Vulnerable To Contamination From The Following?

Upstream industries

(list)

Agricultural/ livestock

farms

Sewer systems such as leaking septic tanks, etc.

Surface faecal run-off

Recreational use by the community

Other (Specify)

Indicate which of the source water protection plans exist?

Zoning Secure fencing

Locked gates

Limits on agriculture

(e.g. phosphorous,

pesticides)

Other (Specify)

Is The Quantity Of The Water Source Sufficient For The Community?

YES

NO

Has the quality of the source water deteriorated or otherwise changed in the last 5 years? If Yes, Explain

YES NO SPECIFY

Is the storage reservoir protected? YES NO SPECIFY CATCHMENT AND RAW WATER SOURCE EVALUATION

List existing risks that could make water unsafe (i.e. cause a deterioration in water quality)

Name the control

measure in place (if any)

Is the control

measure effective (Y/N)?

Likelihood of

occurrence

Consequence of occurrence

Risk Rating

Risk

Priority

L: Low M:

Medium H: High

e.g.

Livestock activity at

water source. Can cause illness from ingestion of

harmful micro-

organisms

Secure fencing

0.8 70 56 L M H

1 L M H 2 L M H 3 L M H

27

SECTION C: TREATMENT, DESIGN AND OPERATION RISK EVALUATION

ITEM 1

Classification of Waterworks

Average volume of water treated daily (ML/day)

Number of users who receive water from the waterworks (people)

Are there any flow meters installed at the waterworks?

Give a brief description of the waterworks in terms of any major events and upgrades that have occurred in the past

What infrastructure development plans exist for the short term?

What infrastructure development plans exist for the long term?

Primary purpose of treatment (Can be more than one)

Turbidity Removal

Colour Removal

DesalinationStabilization / Softening

Algae Removal

Nitrate Removal

Fluoride Removal

Iron and Manganese

Removal

Taste and Odour

Removal Disinfection Other (Specify)

Pre-treatment processes

Chlorination Ozonation Aeration Solids

Removal Other

(Specify)

Main treatment processes Coagulation Flocculation Sedimentation/Flotation Filtration

pH adjustment chemical (if any)

Lime Soda Ash CO2 Other

(Specify)

28

Disinfection (post treatment) Chlorine

Gas HTH Chloramination Other (Specify)

Does the plant comply with the requirements of the occupational safety, health and environmental act (OSH Act 1993)?

YES NO SPECIFY

Does the treated water meet the current standards (SANS 241) for drinking water quality?

YES NO SPECIFY

Are there leaks in the chemical mixing tanks?

YES NO SPECIFY

Is the chemical mixing tank maintained in a clean condition? (i.e. free from deposits/spillage/scum)

YES NO SPECIFY

Are there evident hydraulic surges at the raw water intake of the works?

YES NO SPECIFY

Is the sedimentation tank maintained in a clean condition? (i.e. free from deposits/algal growth/scum)

YES NO SPECIFY

Is the sand on the filter bed even? YES NO SPECIFY Is the filter backwashed according to its design guidelines?

YES NO SPECIFY

Are there mud balls or cracks in the filters?

YES NO SPECIFY

Are there evident cross connections between backwashed and treated waters?

YES NO SPECIFY

Is there evidence of insufficient coagulant dosing?

YES NO SPECIFY

Is the plant able to achieve the required residual chlorine levels?

YES NO SPECIFY

Has the works exceeded 75% of its volume capacity (ML/day)?

YES NO SPECIFY

Does the works have flexibility to meet demands for the next 5 years?

YES NO SPECIFY

Does the plant have a regular supply of treatment chemicals?

YES NO SPECIFY

Are the treatment chemicals stored in accordance with the material safety data sheets (MSDS)?

YES NO SPECIFY

Is the equipment regularly checked for reliability?

YES NO SPECIFY

Is there any back-up equipment for the following: Coagulant dosing pumps Disinfection dosing pumps

YESYES

NO NO

SPECIFY

Is there a back-up for power supply?

YES NO SPECIFY

Is there a routine inspection of maintenance on the plant and of equipment?

YES NO SPECIFY

29

Are there records of maintenance performed on the system?

YES NO SPECIFY

Are there any approved Operational and Maintenance Manuals for each unit process on the plant?

YES NO SPECIFY

Is the Operational and Maintenance Manual being actively used?

YES NO SPECIFY

Does the system have an approved emergency response plan? If yes, what is the frequency of use of the plan?

YES NO SPECIFY

Is the operator consistent in record keeping and providing the appropriate reports throughout the year?

YES NO SPECIFY

Frequency of operational monitoring N: Not done H: More than once daily D: Once Daily W: Once Weekly M: Monthly 2: Every 2 months 3: Every 3 months A: Annually

Turbidity Residual Chlorine

pH Jar Tests

Frequency of compliance monitoring N: Not done H: More than once daily D: Once Daily W: Once Weekly M: Monthly 2: Every 2 months 3: Every 3 months A: Annually

Turbidity Residual Chlorine

pH Metals

Hardness Colour Microbiologi

cal Other

(Specify)

pH Turbidity Chlorine Conductiv

ity

Iron and Mangane

se Jar Tests

Is there proper equipment available to conduct operational monitoring of the following?

YES YES YES YES YES YES

NO NO NO NO NO NO

Is the equipment calibrated?

YES YES YES YES YES YES

NO NO NO NO NO NO

30

Residuals management: Methods of treatment

Coagulant Recovery

Recycling of

Residuals Streams

Discharge to Sewer

Settling Thickening Other

(Specify)

Residuals management: Methods of disposal

Drying bed Sludge dam Land

application Sewer

Other (Specify)

ITEM 2

Number of actual operators Full-time Day time Part-time

Number of operators required Full-time Day time Part-time

What level of training does the operator/s have?

NQF2 NQF4 NQF5 Other (Specify)

NQF2 – Grade 10 NQF4 – Grade 12 NQF5 – Grade 12 + 2

Is the operator currently undergoing training?

YES NO SPECIFY

List the operators’ training needs in order of priority

What level of training does the supervisor have?

NQF2 NQF4 NQF5 Other (Specify)

NQF2 – Grade 10 NQF4 – Grade 12 NQF5 – Grade 12 + 2

Is the supervisor currently undergoing training?

YES NO SPECIFY

List the supervisor’s training needs in order of priority

TREATMENT, DESIGN AND OPERATION RISK EVALUATION

List existing risks that could make water unsafe (i.e. cause a deterioration in water quality)

Name the control

measure in place (if any)

Is the control

measure effective (Y/N)?

Likelihood of

occurrence

Conse-quence of

occurrence

Risk Rating

Risk

Priority

L: Low M: Medium

H: High

e.g.

Optimal pH

prior to coagulation

not achieved. Floc

formation not optimal.

None

1 70 70 L M H

1 L M H 2 L M H 3 L M H

31

SECTION D: DISTRIBUTION RISK EVALUATION ITEM 1 – Primary mains

Is there evidence of the following in the vicinity of the pipe?

Leakage Human/Animal

faeces Solid waste

Excessive algal growth

YES NO YES NO YES NO YES NO

Does the primary main pass through stagnant water?

YES NO SPECIFY

ITEM 2 – On-site Service reservoir/s

Are the vents covered? YES NO SPECIFY Are the inspection covers or concrete around cover damaged or corroded?

YES NO SPECIFY

Is there any observable part of the inside of the tank corroded or damaged (including: ladders, roof struts, walls)?

YES NO SPECIFY

Is there evidence of leakage/cracks on the walls?

YES NO SPECIFY

Can run-off form stagnant pools close to the reservoir?

YES NO SPECIFY

Can stagnant or dirty water collect in valve boxes or washout chambers?

YES NO SPECIFY

Is the reservoir fenced and secure?

YES NO SPECIFY

Is there evidence of human/animal faecal material around the valve box/chamber, reservoir vents and/or inspection covers?

YES NO SPECIFY

Is the reservoir cleaned? If so, how often?

YES NO SPECIFY

Are there any valve leaks? YES NO SPECIFY ITEM 3 – Off-site Service reservoir/s

Are the vents covered? YES NO SPECIFY Are the inspection covers or concrete around cover damaged or corroded?

YES NO SPECIFY

Is there any observable part of the inside of the tank corroded or damaged (including: ladders, roof struts, walls)?

YES NO SPECIFY

Is there evidence of leakage/cracks on the walls?

YES NO SPECIFY

Can run-off form stagnant pools close to the reservoir?

YES NO SPECIFY

Can stagnant or dirty water collect in valve boxes or washout chambers?

YES NO SPECIFY

Is the reservoir fenced and secure?

YES NO SPECIFY

32

Is there evidence of human/animal faecal material around the valve box/chamber, reservoir vents and/or inspection covers?

YES NO SPECIFY

Is the reservoir cleaned? If so, how often?

YES NO SPECIFY

Are there any valve leaks? YES NO SPECIFY ITEM 4 – Booster Stations

Is disinfectant added to the water at the booster station?

YES NO SPECIFY

Is any observable part of the booster station corroded or damaged (including: ladders, roof struts and walls)?

YES NO SPECIFY

Is there evidence of leakage/cracks, etc. in the booster?

YES NO SPECIFY

Can run-off form stagnant pools close to the booster?

YES NO SPECIFY

Can stagnant or dirty water collect in valve boxes?

YES NO SPECIFY

Is the booster station fenced and secure?

YES NO SPECIFY

Is there evidence of faecal material around the valve box/chamber?

YES NO SPECIFY

Is the booster station cleaned? If so, how often

YES NO SPECIFY

Are there any valve leaks? YES NO SPECIFY Is the connecting main leaking? YES NO SPECIFY Are backflow preventers installed in the supply main?

YES NO SPECIFY

ITEM 5 – Valve Boxes/Chambers (Other than those covered as part of service reservoirs and booster stations

Are the valves operational? YES NO SPECIFY Is the valve box cover cracked? YES NO SPECIFY Is the valve corroded? YES NO SPECIFY Does the valve leak? YES NO SPECIFY Is there debris or faecal matter in the valve box/chamber?

YES NO SPECIFY

Is the valve box designed without a washout?

YES NO SPECIFY

Is there stagnant water in the valve box?

YES NO SPECIFY

ITEM 6 – Pipes in the Vicinity of Roads, Drains and Ditches

Are there evident standpipes connected to the valves?

YES NO SPECIFY

Is there a valve box within 1 meter of a road crossing?

YES NO SPECIFY

Is the supply pipe close to the road crossing?

YES NO SPECIFY

Is there evidence of faecal matter in the area surrounding the pipe?

YES NO SPECIFY

33

Is there evidence of leaks around the pipe?

YES NO SPECIFY

Does the pipe cross an open trench/ditch?

YES NO SPECIFY

Is there waste material around the pipe?

YES NO SPECIFY

Is the pipe submerged in stagnant water?

YES NO SPECIFY

Is the pipe visibly damaged/cracked/leaking?

YES NO SPECIFY

ITEM 7 – Standpipes/House Connections

Do any standpipes leak? YES NO SPECIFY Does surface water collect around any standpipe?

YES NO SPECIFY

Are the supply pipes in the vicinity of the stand pipes exposed?

YES NO SPECIFY

Is there any faecal matter on the ground within 10m of any standpipe?

YES NO SPECIFY

Is the main supply pipe submerged in stagnant water?

YES NO SPECIFY

Are there solid waste dumps within 10m from the standpipes?

YES NO SPECIFY

Does the main supply pipe pass through sewage/pit latrines/septic tank/ foul water bodies?

YES NO SPECIFY

Does the main pipe cross a drain/ditch?

YES NO SPECIFY

DISTRIBUTION RISK EVALUATION

List existing risks that could make water unsafe (i.e. cause a deterioration in water quality)

Name the control

measure in place (if any)

Is the control

measure effective (Y/N)?

Likelihood of

occurrence

Consequence of occurrence

Risk Rating

Risk

Priority

L: Low M:

Medium H: High

e.g.

Water

contaminated due to

backflow

Positive pressure

maintained in the

distribution system

0.5 70 35 L M H

1 L M H2 L M H3 L M H

34

AN

NE

XU

RE

B:

CO

RR

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S

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on

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(R

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d S

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sou

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mfu

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to r

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turb

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ay

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oppi

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supp

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and

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wat

er

rest

rictio

n st

rate

gy

and

impl

em

ent

wh

en

wat

er le

vels

fall.

Van

dal

ism

or

sabo

tage

ma

y p

ollu

te th

e w

ater

with

ch

emic

als

or m

icro

bes

or

dam

age

equ

ipm

ent

and

in

fras

truc

ture

.

Hea

lth a

nd

aest

hetic

impa

cts

from

the

pres

en

ce o

f ch

emic

als.

Ill

ness

from

pre

senc

e of

mic

ro-o

rgan

ism

s.

Inte

rrup

tion

to s

upp

ly.

Lim

it ac

cess

in th

e vi

cini

ty o

f wat

er in

take

s.

Mak

e su

re c

atch

men

t is

prot

ect

ed (

e.g.

reg

ula

r pa

trol

s).

Inta

ke s

cree

ns b

ecom

e cl

ogge

d or

dam

age

d.

Sup

ply

ma

y be

red

uce

d.

Che

ck s

cre

ens

regu

larl

y an

d re

mov

e m

ater

ial.

Bus

hfire

s ca

n re

sult

in fi

re r

etar

dant

s in

the

wat

er

sour

ce.

Loss

of v

eget

atio

n ca

n re

sult

in th

e pr

ese

nce

of t

urbi

dity

an

d or

gani

c m

atte

r.

Hea

lth r

isk

and

aes

thet

ic r

isk

from

pre

senc

e of

ch

emic

als.

A

n in

cre

ase

d tu

rbid

ity a

nd v

ege

tatio

n in

terf

ere

s w

ith

disi

nfec

tion

resu

ltin

g in

illn

ess

from

pre

senc

e of

mic

ro-

orga

nism

s.

Mor

e D

BP

s al

so p

rod

uce

d.

Dev

elop

and

impl

eme

nt h

azar

d re

duc

tion

stra

tegi

es.

Mai

nta

in fi

re a

cces

s ro

ads.

M

aint

ain

cont

act

with

loca

l fir

e se

rvic

es.

Iden

tify

appr

opria

te fi

re r

etar

dan

ts.

35

H

azar

d

Ris

kC

orr

ect

ive

acti

on

/sB

OR

EH

OL

ES

Live

stoc

k, h

uman

act

ivity

at

wat

er s

ourc

e. S

hal

low

bo

reho

les

in h

ighl

y p

erm

eabl

e so

ils o

r fr

actu

red

rock

aq

uife

rs a

re m

ore

vuln

era

ble

to c

onta

min

atio

n.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

H

ealth

an

d ae

sthe

tic im

pact

s fr

om c

hem

ical

s.

Ens

ure

prot

ectiv

e m

easu

res

are

mai

nta

ine

d, e

.g.

min

imum

pro

tect

ion

zon

e (e

.g. 5

0m)

arou

nd

bore

hole

. (L

arg

e bu

ffer

zone

s m

ay

be

requ

ired

for

sha

llow

bor

eho

le

or fo

r pe

rmea

ble

soils

or

frac

ture

d ro

ck a

qui

fers

).

Acc

ess

prev

en

tion.

Li

mits

on

agr

icul

ture

. C

onto

ur b

ank

s to

red

uce

eros

ion.

G

roun

dw

ate

r m

ay

cont

ain

heal

th r

elat

ed c

hem

ical

s (e

.g.

arse

nic

, bar

ium

, flu

orid

e, u

rani

um, r

adiu

m)

as a

res

ult o

f lo

cal g

eolo

gy.

Hea

lth r

isk

or a

esth

etic

imp

act o

f che

mic

als.

T

est g

roun

dw

ate

r fo

r he

alth

re

late

d ch

emic

als

bef

ore

com

mis

sio

ning

the

bore

hol

e fo

r a

drin

king

wat

er s

upp

ly

Sur

face

wat

er e

nter

ing

a b

ore

hole

can

incr

ease

the

turb

idity

and

/or

ma

y co

ntai

n th

e dr

oppi

ngs

of a

nim

als

or

bird

s w

hic

h co

ntai

n h

arm

ful m

icro

-org

anis

ms.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

D

isin

fect

ion

affe

cted

. In

crea

sed

org

ani

c m

atte

r le

ad

s to

pro

duct

ion

of D

BP

s.

Con

stru

ct b

ore

hole

to p

reve

nt th

e en

try

of s

urf

ace

wa

ter.

E

nsur

e st

ruct

ures

rem

ain

inta

ct a

nd th

at r

epa

irs

are

initi

ated

wh

en f

aults

are

re

port

ed (

e.g.

cra

ckin

g).

Sea

l pum

ps a

nd

wa

ter

outle

ts to

pre

vent

the

entr

y of

su

rfac

e w

ater

. S

urro

und

the

bor

ehol

e w

ith a

con

cret

e sl

ab/p

linth

at l

eas

t 2m

in d

iam

eter

slo

ping

aw

ay

from

the

bore

hole

he

ad.

Enc

ase

the

bore

hole

in a

wat

ert

ight

con

cret

e se

al.,

e.g.

at

leas

t 3m

in d

epth

to p

reve

nt th

e en

try

of s

urfa

ce w

ate

r.

The

sea

l sho

uld

ext

end

at le

ast

30c

m a

bove

the

gro

und

to

pre

vent

the

entr

y of

sur

face

wa

ter.

Mak

e su

re th

at th

e ai

r ve

nts/

air

lines

face

do

wn

war

ds, a

re s

cree

ned

and

are

ab

ove

the

leve

l of a

1 in

100

yea

r flo

od.

C

ap a

nd s

eal

mon

itorin

g b

oreh

ole

in th

e vi

cini

ty.

Van

dal

ism

or

sabo

tage

ma

y p

ollu

te th

e w

ater

with

ch

emic

als

or m

icro

bes

or

dam

age

equ

ipm

ent

and

in

fras

truc

ture

.

Hea

lth a

nd

aest

hetic

impa

cts

from

the

pres

en

ce o

f ch

emic

als.

Ill

ness

from

pre

senc

e of

mic

ro-o

rgan

ism

s.

Inte

rrup

tion

to s

upp

ly.

Pro

tect

the

bore

hole

hea

d a

nd

pum

ps.

Reg

ular

pat

rols

of a

rea.

Wat

er m

ay

con

tain

nat

ural

ly o

ccur

ring

iron

and

m

ang

anes

e

Aes

thet

ic im

pa

cts

on c

olou

r a

nd ta

ste

(pot

en

tial f

or

stai

ning

).

Opt

iimiz

ew

ate

r tr

eatm

ent p

roce

sses

to r

emov

e iro

n a

nd

man

gan

ese.

36

H

azar

d

Ris

kC

orr

ect

ive

acti

on

/sS

PR

ING

S

Spr

ing

mus

t be

des

igne

d to

pro

tect

spr

ing

fro

m

lives

tock

, hum

an a

ctiv

ity a

t w

ater

sou

rce.

S

hallo

w b

ore

hol

es in

hig

hly

per

mea

ble

soils

or

frac

ture

d ro

ck a

quife

rs a

re m

ore

vuln

erab

le to

con

tam

inat

ion.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

H

ealth

an

d ae

sthe

tic im

pact

s fr

om c

hem

ical

s.

Ens

ure

prot

ectiv

e m

easu

res

are

mai

nta

ine

d, e

.g.

min

imum

pro

tect

ion

zon

e (e

.g. 5

0m)

arou

nd

bore

hole

. (L

arg

e bu

ffer

zone

s m

ay

be

requ

ired

for

sha

llow

bo

reho

le o

r fo

r pe

rme

able

soi

ls o

r fr

actu

red

rock

aq

uife

rs).

A

cces

s pr

eve

ntio

n.

Lim

its o

n a

gric

ultu

re.

App

ropr

iate

sp

ring

enc

asem

ent

. G

roun

dw

ate

r/sp

ring

wat

er m

ay

cont

ain

hea

lth r

elat

ed

chem

ical

s (e

.g.

arse

nic,

bar

ium

, flu

orid

e, u

rani

um,

radi

um)

as a

re

sult

of lo

cal g

eol

og

y.

Hea

lth r

isk

or a

esth

etic

imp

act o

f che

mic

als

Tes

t gro

und

wa

ter

for

heal

th r

ela

ted

chem

ica

ls b

efor

e co

mm

issi

oni

ng th

e bo

reh

ole

for

a dr

inki

ng w

ater

sup

ply

.

Van

dal

ism

or

sabo

tage

ma

y p

ollu

te th

e w

ater

with

ch

emic

als

or m

icro

bes

or

dam

age

equ

ipm

ent

and

in

fras

truc

ture

.

Hea

lth a

nd

aest

hetic

impa

cts

from

the

pres

en

ce o

f ch

emic

als.

Ill

ness

from

pre

senc

e of

mic

ro-o

rgan

ism

s.

Inte

rrup

tion

to s

upp

ly.

Pro

tect

the

spri

ng a

nd

pum

ps.

Mak

e su

re c

atch

men

t is

prot

ect

ed (

secu

re fe

ncin

g,

lock

ed

gate

s, r

egu

lar

patr

ols)

.

Wat

er m

ay

con

tain

nat

ural

ly o

ccur

ring

iron

and

m

ang

anes

e.

Aes

thet

ic im

pa

cts

on c

olou

r a

nd ta

ste

(pot

en

tial f

or

stai

ning

).

Opt

iimiz

ew

ate

r tr

eatm

ent p

roce

sses

to r

emov

e iro

n a

nd

man

gan

ese

S

urfa

ce w

ater

ent

erin

g th

e b

ore

hole

can

incr

ease

the

turb

idity

and

/or

ma

y co

ntai

n th

e dr

oppi

ngs

of a

nim

als

or

bird

s w

hic

h co

ntai

n h

arm

ful m

icro

-org

anis

ms.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

D

isin

fect

ion

affe

cted

. In

crea

sed

org

ani

c m

atte

r le

ad

s to

pro

duct

ion

of D

BP

s.

Con

stru

ct s

prin

g en

case

me

nt to

pre

vent

the

entr

y of

su

rfac

e w

ater

.

Ens

ure

stru

ctur

es r

emai

n in

tact

and

that

rep

air

s ar

e in

itiat

ed w

hen

fau

lts a

re r

epo

rted

(e.

g. c

rack

ing)

. E

stab

lish

a m

inim

um p

rote

ctio

n zo

ne (

e.g.

50

m)

arou

nd

each

spr

ing.

M

ake

sure

eac

h sp

ring

has

a su

rfac

e dr

ain

age

ditc

h lo

cate

d up

hill

from

the

sour

ce t

o in

terc

ept a

nd

dive

rt

surf

ace

wat

er r

un-o

ff.

Mak

e su

re s

prin

g ha

s a

n im

per

mea

ble

laye

r of

con

cret

e be

hin

d th

e sp

ring

box

or e

nca

sem

ent a

nd

abov

e th

e e

ye

of th

e sp

ring.

37

Haz

ard

R

isk

Co

rre

ctiv

e ac

tio

n/s

IMP

OU

ND

ME

NT

S (

DA

MS

) U

rba

n ar

eas

and

was

tew

ate

r di

sch

arge

(p

erm

itted

or

una

utho

rised

) ca

n le

ad to

po

llutio

n of

wat

er w

ith h

arm

ful

orga

nism

s. E

xten

t of p

ollu

tion

will

be

depe

nden

t on

leve

l of

trea

tmen

t an

d m

ana

gem

ent

of s

ew

age

col

lect

ion

syst

em, a

nd

ext

ent o

f dilu

tion

in th

e ca

tchm

ent

sto

rage

.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

If

ther

e is

a lo

calis

ed

trea

tme

nt o

f w

aste

wa

ter,

then

m

inim

ized

isch

arge

into

the

wat

er b

ody.

If w

aste

wat

er is

di

sch

arge

d, m

ake

sure

that

the

leve

l of t

rea

tmen

t is

high

to

red

uce

the

impa

cts

of h

arm

ful m

icro

-org

anis

ms

on

the

rece

ivin

g w

ater

bod

y.

Whe

reve

r p

ossi

ble,

use

land

bas

ed r

ecyc

ling.

Mak

e su

re

sew

age

col

lect

ion

syst

ems

are

pro

perl

y en

gin

eere

d an

d w

ell

ma

inta

ine

d an

d th

at s

pills

and

ove

rflo

ws

are

man

age

d du

rin

g st

orm

eve

nts.

D

evel

op e

mer

gen

cy a

nd

inci

den

t pla

ns to

de

al w

ith

wa

ste

wat

er s

pills

. M

ake

sure

that

the

dom

estic

wa

ste

wat

er s

yste

ms

are

not n

ear

the

wat

er b

odie

s (e

.g. a

t lea

st 5

0 m

aw

ay

from

so

urce

).

Urb

an

area

s ca

n po

llute

wat

er

via

una

utho

rised

di

sch

arge

of c

hem

ical

s or

spi

lls fr

om s

tore

d ch

emic

als.

H

ealth

or

aest

het

ic im

pact

cau

sed

by

chem

ical

s.

Con

duct

com

mun

ity e

duc

atio

n p

rogr

amm

es.

Rec

reat

ion

al a

ctiv

ities

can

ca

use:

mic

rob

ial (

faec

al

wa

ste)

an

d ch

em

ical

(bo

atin

g) c

onta

min

atio

n an

d so

il er

osio

n (o

ff ro

ad

vehi

cles

).

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

H

ealth

an

d ae

sthe

tic im

pact

s.

Incr

ease

d tu

rbid

ity c

an in

terf

ere

with

dis

infe

ctio

n.

Incr

ease

d or

ga

nic

mat

ter

will

giv

e ris

e to

an

incr

ease

in

DB

Ps.

Ens

ure

toile

ts w

ith s

ew

er

ma

nag

emen

t and

rub

bis

h bi

ns

are

ava

ilabl

e.

Con

duct

pu

blic

edu

catio

n pr

ogr

amm

es.

Res

tric

t act

iviti

es w

her

e re

quir

ed.

Was

tew

ater

dis

char

ge

can

lead

to a

n in

crea

se in

nu

trie

nt le

vels

in c

atch

men

ts a

nd r

eser

voirs

. In

crea

sed

nutr

ient

s ca

n le

ad t

o th

e fo

rmat

ion

of a

lgae

. M

ake

sure

wa

ste

wa

ter

stor

ages

are

pro

perly

co

nstr

ucte

d a

nd

lined

so

that

the

y do

not

leak

. D

evel

op e

mer

gen

cy a

nd

inci

den

t res

pons

e p

lans

to d

eal

w

ith w

aste

wa

ter

spill

s.

Urb

an

area

s ca

n be

a s

ourc

e fo

r tu

rbid

ity,

litte

r an

d p

lant

de

bris

in th

e w

ater

bod

y.

Ph

ysic

al q

ualit

y of

wat

er p

oor.

In

crea

sed

turb

idity

and

org

ani

c m

atte

r ca

n in

terf

ere

with

di

sinf

ectio

n an

d le

ad

to th

e fo

rmat

ion

of D

BP

s.

Con

duct

com

mun

ity e

duc

atio

n p

rogr

amm

es a

bout

the

nee

d to

min

imiz

epo

llutio

n of

wat

er b

odi

es b

y lit

ter,

de

bris

and

pla

nt m

ater

ials

A

cces

s to

res

erv

oirs

can

lead

to

acci

dent

al d

amag

e to

in

fras

truc

ture

and

incr

ease

d co

ntam

inat

ion

from

spi

lls

Hea

lth o

r ae

sth

etic

impa

ct o

f che

mic

als.

Li

mit

acce

ss.

Agr

icul

tura

l act

iviti

es in

volv

ing

live

stoc

k ca

n po

llute

the

wat

er w

ith h

arm

ful o

rga

nism

s. T

he c

once

ntra

tion

of

pollu

tant

is d

epen

den

t on

inte

nsity

of a

ctiv

ity a

nd le

vel o

f ac

cess

to s

tora

ge a

rea.

Illne

ss fr

om in

ges

tion

of h

arm

ful o

rgan

ism

s.

Pre

vent

live

sto

ck a

cces

s b

y fe

ncin

g.

Red

uce

imp

acts

of s

urfa

ce r

un-o

ff ca

rryi

ng f

aeca

l was

te

thro

ugh

the

use

of r

ipar

ian

zone

s.

Min

imiz

eint

ensi

ve li

vest

ock

activ

ity n

ear

imp

oun

dmen

ts.

Agr

icul

tura

l pra

ctic

es m

ay

lea

d to

con

tam

ina

tion

by

toxi

c ch

emic

als

incl

udi

ng

pest

icid

es, s

pilla

ge o

f die

sel a

nd

petr

oleu

m p

rod

ucts

.

Hea

lth o

r ae

sth

etic

impa

cts

of c

hem

ical

s.

Intr

oduc

e co

des

of p

ract

ice

to fa

rmer

s to

impr

ove

man

age

me

nt a

nd m

inim

izet

he

ent

ry o

f pes

ticid

es in

to

the

wat

er b

ody.

M

inim

izet

he u

se/s

tora

ge o

f die

sel w

ithin

the

catc

hmen

t. P

rote

ct w

ith b

und

ing

and

ph

ysic

al b

arrie

rs to

con

tain

sp

ills.

38

Haz

ard

R

isk

Co

rre

ctiv

e ac

tio

n/s

Agr

icul

tura

l pra

ctic

es m

ay

incr

ease

nut

rient

leve

ls in

w

ater

du

e to

the

entr

y of

fert

ilise

rs o

r ni

trog

eno

us

com

poun

ds a

ssoc

iate

d w

ith li

vest

ock.

Incr

ease

d nu

trie

nts

can

lead

to

the

gro

wth

of a

lga

e.

Cer

tain

spe

cie

s of

alg

ae c

onta

in to

xins

an

d ca

n ha

ve

serio

us h

ealth

effe

cts.

C

erta

in s

peci

es

of a

lgae

pro

duc

e ta

ste

and

odo

ur

prob

lem

s.

Intr

oduc

e co

des

of p

ract

ice

to im

prov

e m

ana

gem

ent

by

farm

ers

and

min

imiz

ethe

ent

ry o

f nut

rient

s fr

om

agric

ultu

ral a

ctiv

ities

in w

ater

bod

ies.

For

estr

y in

volv

ing

the

dev

elop

men

t of t

imbe

r pl

ant

atio

ns

can

lead

to th

e d

isch

arge

of p

estic

ides

an

d h

erbi

cide

s.

Hea

lth im

pact

of c

hem

ica

ls.

Dev

elop

cod

es o

f pra

ctic

e to

ens

ure

the

use

of

pest

icid

es o

r h

erbi

cide

s is

un

dert

ake

n in

a m

ann

er th

at

that

min

imis

es im

pact

s on

wat

er b

odie

s.

Dev

elop

inci

de

nt e

mer

genc

y pl

ans

. A

gric

ultu

ral p

ract

ices

and

live

stoc

k ca

n ca

use

ero

sio

n ar

ound

the

wat

er b

ody

and

lead

to a

n in

crea

se in

tu

rbid

ity.

Incr

ease

d tu

rbid

ity c

an in

terf

ere

with

dis

infe

ctio

n an

d le

ad

to th

e fo

rmat

ion

of D

BP

s (in

crea

ses

the

risk

of

mic

ro-o

rgan

ism

s to

be

pres

ent

in th

e w

ater

).

Intr

oduc

e co

des

of p

ract

ice

to m

inim

izee

rosi

on

and

poss

ible

impa

cts

on w

ater

qu

ality

with

in b

odi

es.

For

estr

y ca

n ca

use

eros

ion

on th

e w

ater

bod

y an

d le

ad

to a

n in

crea

se in

turb

idity

. In

crea

sed

turb

idity

can

inte

rfe

re w

ith d

isin

fect

ion

and

lea

d to

the

form

atio

n of

DB

Ps

(incr

ease

s th

e ris

k of

m

icro

-org

anis

ms

to b

e pr

ese

nt in

the

wat

er).

Intr

oduc

e co

des

of p

ract

ice

to m

inim

izee

rosi

on

and

poss

ible

impa

cts

on w

ater

qu

ality

with

in b

odi

es

Mak

e su

re th

at d

isus

ed

are

as a

re r

ehab

ilita

ted.

A

fter

heav

y ra

in,

wat

er e

nter

ing

imp

oun

dme

nt m

ay

be

turb

id a

nd c

ont

ain

drop

pin

gs o

f ani

ma

ls/b

irds

and

cont

ain

high

leve

ls o

f org

ani

c m

atte

r.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

D

isin

fect

ion

affe

cted

. In

crea

sed

org

ani

c m

atte

r le

ad

s to

pro

duct

ion

of D

BP

s.

Use

alte

rnat

e so

urce

s of

wat

er,

sw

itch

supp

ly u

ntil

turb

idity

and

was

te m

ater

ial s

ettle

s.

Mon

itor

rain

fall

patte

rns

in c

atch

men

t to

deve

lop:

Str

ateg

ies

to m

ana

ge r

ainf

all

U

nder

stan

din

g of

impa

ct o

f rai

nfal

l on

wat

er q

ualit

y D

ead

anim

als.

Ill

ness

from

ing

estio

n of

har

mfu

l mic

ro-o

rga

nism

s.

Tas

te a

nd o

dour

pro

ble

ms.

Reg

ular

pat

rols

to

rem

ove

dea

d an

imal

s.

Low

flo

w, h

igh

nutr

ient

leve

ls a

nd w

arm

con

ditio

ns –

can

m

ake

cyan

oba

cter

ial a

nd a

lga

l gro

wth

mor

e lik

ely.

T

aste

and

odo

ur p

rob

lem

s ca

used

by

cya

noba

cter

ia.

Som

e sp

ecie

s of

cya

nob

acte

ria

prod

uce

toxi

ns.

Dra

w h

igh

est q

ualit

y w

ater

an

d ha

ve v

aria

ble

dep

th o

ff-ta

kes

to a

void

alg

al g

row

th.

App

ly a

lga

ecid

es if

req

uire

d.

Wat

er s

trat

ifica

tion

can

lea

d to

low

oxy

gen

co

nce

ntra

tions

at l

ow

er le

vels

.

Pro

mot

es a

lgal

gro

wth

an

d re

leas

es F

e an

d M

n fr

om

sedi

men

ts.

Tas

te a

nd o

dour

pro

ble

ms

caus

ed b

y cy

ano

bact

eria

an

d F

e an

d M

n. R

ed/

bro

wn

susp

ens

ions

in w

ater

cau

se

stai

ning

. S

ome

spec

ies

of c

yano

bac

teri

a pr

oduc

e to

xins

.

Dra

w h

igh

est q

ualit

y w

ater

an

d ha

ve v

aria

ble

dep

th o

ff-ta

kes

to a

void

alg

al g

row

th.

Fal

ling

wat

er le

vels

du

e to

dro

ught

or

dra

wd

ow

n of

wat

er

bod

y.

Tur

bidi

ty fr

om e

rosi

on, p

rese

nce

of ir

on a

nd m

anga

nese

, in

cre

ased

org

ani

c m

atte

r (p

rodu

ctio

n of

DB

Ps)

, aes

thet

ic

qua

lity

of w

ater

affe

cted

by

pres

ence

of a

lga

e, F

e an

d M

n an

d so

me

alg

ae p

rodu

ce to

xins

.

Use

alte

rnat

e so

urce

of

wat

er if

ava

ilabl

e, d

eve

lop

wat

er

rest

rictio

n st

rate

gy

and

impl

em

ent

wh

en

wat

er le

vels

fall.

Bus

hfire

s ca

n re

sult

in fi

re r

etar

dant

s in

the

wat

er

sour

ce.

Loss

of v

eget

atio

n ca

n re

sult

in th

e pr

ese

nce

of t

urbi

dity

an

d or

gani

c m

atte

r.

Hea

lth r

isk

and

aes

thet

ic r

isk

from

pre

senc

e of

ch

emic

als.

A

n in

cre

ase

d tu

rbid

ity a

nd v

ege

tatio

n in

terf

ere

s w

ith

disi

nfec

tion

resu

ltin

g in

illn

ess

from

pre

senc

e of

mic

ro-

orga

nism

s.

Mor

e D

BP

s al

so p

rod

uce

d.

Dev

elop

and

impl

eme

nt h

azar

d re

duc

tion

stra

tegi

es.

Mai

nta

in fi

re a

cces

s ro

ads.

M

aint

ain

cont

act

with

loca

l fir

e se

rvic

es.

Iden

tify

appr

opria

te fi

re r

etar

dan

ts.

39

Haz

ard

R

isk

Co

rre

ctiv

e ac

tio

n/s

Van

dal

ism

or

sabo

tage

ma

y p

ollu

te th

e w

ater

with

ch

emic

als

or m

icro

bes

or

dam

age

equ

ipm

ent

and

in

fras

truc

ture

.

Hea

lth a

nd

aest

hetic

impa

cts

from

the

pres

en

ce o

f ch

emic

als.

Ill

ness

from

pre

senc

e of

mic

ro-o

rgan

ism

s.

Inte

rrup

tion

to s

upp

ly.

Lim

it ac

cess

in th

e vi

cini

ty o

f wat

er in

take

s.

Mak

e su

re c

atch

men

t is

prot

ect

ed (

secu

re fe

ncin

g,

lock

ed

gate

s, r

egu

lar

patr

ols)

.

Inta

ke s

cree

ns b

ecom

e cl

ogge

d or

dam

age

d.

Sup

ply

ma

y be

red

uce

d.

Che

ck s

cre

ens

regu

larl

y an

d re

mov

e m

ater

ial.

PR

E-O

XID

AT

ION

Und

er d

osin

g o

f ox

idan

t due

to:

D

osin

g m

alfu

nctio

n

P

ow

er f

ailu

re

O

xid

ant s

uppl

y ru

ns o

ut

In

crea

sed

dem

and

of r

aw

wat

er

Incr

ease

d bi

olo

gica

l gro

wth

of

pla

nts

lea

din

g to

clo

gge

d fil

ters

and

tast

e a

nd o

dou

r pr

obl

ems.

D

ecre

ased

re

mov

al o

f par

ticle

s an

d th

e ha

rmfu

l mic

ro-

orga

nism

s th

at a

dher

e to

the

m in

crea

sing

the

risk

of

illn

ess.

In

ade

quat

e re

mov

al o

f iro

n a

nd m

anga

nese

lead

ing

to

pres

enc

e of

re

d-br

ow

n a

nd

blac

kish

sus

pen

sion

s th

at

caus

e st

aini

ng a

nd ta

ste

prob

lem

s.

Inst

all a

larm

s to

wa

rn o

f int

erru

ptio

n of

dos

ing.

W

here

chl

orin

e is

dos

ed, m

easu

re r

esid

ual c

hlor

ine

leve

ls a

s fe

edb

ack

cont

rol o

f dos

ing

rate

to

acco

mm

oda

te c

han

ge in

qua

lity

of s

ourc

e w

ate

r.

Whe

re o

ther

oxi

dant

s ar

e us

ed,

test

oxi

dan

t de

ma

nd

regu

larl

y a

nd a

djus

t dos

age

rate

as

requ

ired

. H

ave

bac

k-up

po

we

r su

pply

or

tem

pora

ry d

osi

ng

equ

ipm

ent

. R

egul

arly

cal

ibra

te m

onito

ring

sys

tem

s.

Car

ry o

ut r

egul

ar m

aint

ena

nce

wo

rk o

n e

quip

men

t.

Mai

ntai

n ox

idan

t st

ocks

. O

verd

osin

g of

oxi

dan

t du

e to

dos

ing

syst

em m

alfu

nctio

n or

dec

reas

ed

dem

and

of w

ate

r.

Hea

lth a

nd

aest

hetic

impa

cts

of c

hem

ica

ls.

Inst

all f

low

pro

port

iona

l dos

ing.

M

onito

r am

oun

ts o

f che

mic

als

used

by

chec

king

leve

ls

in d

osin

g ta

nks.

W

here

chl

orin

e is

dos

ed, m

easu

re r

esid

ual c

hlor

ine

leve

ls a

s fe

edb

ack

cont

rol o

f dos

ing

rate

. W

here

oth

er o

xida

nts

are

use

d, te

st o

xid

ant

dem

and

re

gula

rly

and

adj

ust d

osag

e ra

te a

s re

quire

d.

Reg

ular

ly c

alib

rate

mon

itori

ng s

yste

ms.

C

arry

out

reg

ular

mai

nte

nanc

e w

ork

on

equ

ipm

ent.

P

re-o

xida

tion

caus

es c

yano

bact

eria

to b

urst

and

re

leas

e to

xins

. T

oxin

s ca

n h

ave

serio

us h

eal

th e

ffect

s.

Can

pro

duce

tast

e an

d od

our

pro

blem

s.

Sto

p pr

e-o

xid

atio

n. C

ons

ider

the

use

of a

n a

ppro

ved

alg

aeci

de.

Tre

atm

ent c

hem

ical

s of

po

or q

ualit

y.

Pre

-oxi

datio

n le

ss e

ffect

ive.

In

trod

uctio

n of

haz

ardo

us c

onta

min

ant

s in

to th

e w

ater

. M

ake

sure

ch

em

ical

su

pplie

r is

cer

tifie

d an

d do

not

hav

e co

ntam

inan

t le

vels

that

exc

ee

d gu

idel

ine

valu

es.

CO

AG

UL

AT

ION

, F

LO

CC

UL

AT

ION

an

d S

ED

IME

NT

AT

ION

Dos

ing

mal

fun

ctio

n ca

n re

duce

floc

form

atio

n an

d th

us

the

inef

ficie

nt r

emov

al o

f har

mfu

l mic

ro-o

rgan

ism

s,

orga

nic

mat

eria

l., c

olou

r a

nd t

urbi

dity

.

Illne

ss fr

om th

e in

gest

ion

of h

arm

ful m

icro

-org

anis

ms.

P

oor

phys

ical

qua

lity.

In

crea

sed

turb

idity

and

org

ani

c m

atte

r ca

n in

terf

ere

with

di

sinf

ectio

n an

d le

ad

to th

e fo

rmat

ion

of D

BP

s.

Mon

itor

flow

ra

te o

f coa

gula

nt w

ith a

utom

atic

or

man

ual

adju

stm

ent o

f che

mic

al d

osin

g.

Inst

all a

larm

s to

war

n of

pu

mp

failu

re.

Inst

all s

tand

by

coag

ula

nt p

umps

. M

ake

sure

that

pla

nt d

esig

n is

ade

qua

te to

sup

por

t pea

k lo

ads

. Don

’t o

per

ate

plan

t at f

low

s th

at e

xce

ed

capa

city

. C

arry

out

rou

tine

mai

nten

ance

and

ca

libra

tion

of

chem

ical

dos

ing

equ

ipm

ent

, mon

itori

ng s

yste

ms

and

alar

ms.

M

ake

sure

that

pro

ced

ures

are

in p

lace

for

aut

omat

ic

back

-up

pow

er

or e

mer

genc

y sh

ut-d

ow

n a

nd s

tart

-up.

40

Haz

ard

R

isk

Co

rre

ctiv

e ac

tio

n/s

Che

mic

al s

upp

ly r

uns

out

so

trea

tmen

t effe

ctiv

ely

stop

s.

Inab

ility

to p

rovi

de t

reat

me

nt in

crea

ses

the

risk

of i

llnes

s fr

om th

e in

gest

ion

of h

arm

ful m

icro

-org

anis

ms.

P

oor

phys

ical

qua

lity.

In

crea

sed

turb

idity

and

org

ani

c m

atte

r ca

n in

terf

ere

with

di

sinf

ectio

n an

d le

ad

to th

e fo

rmat

ion

of D

BP

s.

Mak

e su

re th

at s

uffic

ient

che

mic

al s

tock

s ar

e m

aint

ain

ed.

E

stab

lish

a pr

oce

dure

for

regu

lar

chec

king

of

stor

age

tank

leve

ls.

Hav

e a

larm

s in

the

chem

ica

l sup

ply

tank

s to

indi

cate

w

he

n le

vels

are

low

. La

rge

cha

nges

in fl

ow

rat

e or

tur

nin

g th

e pl

ant

on/

off c

an

impa

ir co

agul

atio

n a

nd fl

occu

latio

n.

Inab

ility

to p

rovi

de tr

eatm

ent

incr

ease

s th

e ri

sk o

f illn

ess

form

the

inge

stio

n of

har

mfu

l mic

ro-o

rgan

ism

s.

Poo

r ph

ysic

al q

ualit

y.

Incr

ease

d tu

rbid

ity a

nd o

rga

nic

mat

ter

can

inte

rfer

e w

ith

disi

nfec

tion

and

lea

d to

the

form

atio

n of

DB

Ps.

Est

ablis

h pr

oced

ure

for

star

t-up

an

d sh

ut-d

ow

n of

pl

ants

. E

nsur

e d

osin

g is

flo

w p

aced

and

ver

ify th

at c

han

ges

in

flow

lead

to a

ctua

l ch

ange

s in

che

mic

al d

ose

rate

s.

Poo

r co

ntro

l of p

H a

nd

alka

linity

can

re

duce

coa

gul

atio

n an

d flo

c fo

rmat

ion.

Inab

ility

to p

rovi

de tr

eatm

ent

incr

ease

s th

e ri

sk o

f illn

ess

form

the

inge

stio

n of

har

mfu

l mic

ro-o

rgan

ism

s.

Poo

r ph

ysic

al q

ualit

y.

Incr

ease

d tu

rbid

ity a

nd o

rga

nic

mat

ter

can

inte

rfer

e w

ith

disi

nfec

tion

and

lea

d to

the

form

atio

n of

DB

Ps.

Mai

nta

in o

ptim

um p

H a

nd

alka

linity

for

coag

ula

nts

and

flocc

ulan

ts a

s se

t by

ma

nufa

ctur

er’s

spe

cific

atio

ns a

nd/

or b

ase

d on

pre

vio

us e

xper

ienc

e fr

om o

pera

ting

trea

tmen

t pla

nt.

Use

jar

test

s to

est

ablis

h op

timum

pH

an

d ve

rify

dur

ing

pla

nt o

pera

tion

.

Flo

ccul

atio

n a

nd

part

icle

rem

ova

l can

be

red

uced

if

mix

ing

of c

hem

ical

s is

poo

r.

The

re is

not

en

oug

h co

ntac

t tim

e fo

r flo

c fo

rmat

ion

or

floc

does

not

set

tle p

rop

erly

.

Inab

ility

to p

rovi

de tr

eatm

ent

incr

ease

s th

e ri

sk o

f illn

ess

form

the

inge

stio

n of

har

mfu

l mic

ro-o

rgan

ism

s.

Poo

r ph

ysic

al q

ualit

y.

Incr

ease

d tu

rbid

ity a

nd o

rga

nic

mat

ter

can

inte

rfer

e w

ith

disi

nfec

tion

and

lea

d to

the

form

atio

n of

DB

Ps.

Des

ign

plan

t to

ens

ure

that

mix

ing

is a

dequ

ate

at a

ll flo

w

rate

s.

Do

not o

per

ate

pla

nt a

t flo

w r

ate

s th

at e

xce

ed d

esig

n ca

paci

ty.

If m

ixin

g is

poo

r, a

lter

the

dosi

ng p

oin

t or

intr

oduc

e lo

nge

r pi

pes

or p

ipe

ben

ds to

impr

ove

mix

ing.

M

ake

sure

that

an

y re

cycl

e st

ream

s (f

rom

filte

r ba

ckw

ash

or

slud

ge

stor

age)

are

not

inte

rfer

ing

with

flo

ccul

atio

n.

Cha

nges

in r

aw

wat

er q

ual

ity c

an o

ccur

eith

er

seas

ona

lly o

r fo

llow

ing

eve

nts

such

as

bush

fires

or

flood

s.

If do

sing

of c

oagu

lant

an

d flo

ccul

ent

is n

ot m

odifi

ed in

re

spo

nse

to w

ate

r qu

ality

ch

ange

s, tr

eatm

ent w

ill b

e im

pair

ed.

Inab

ility

to p

rovi

de tr

eatm

ent

incr

ease

s th

e ri

sk o

f illn

ess

form

the

inge

stio

n of

har

mfu

l mic

ro-o

rgan

ism

s.

Poo

r ph

ysic

al q

ualit

y.

Incr

ease

d tu

rbid

ity a

nd o

rga

nic

mat

ter

can

inte

rfer

e w

ith

disi

nfec

tion

and

lea

d to

the

form

atio

n of

DB

Ps.

Mon

itor

raw

wa

ter

qual

ity fo

r p

hys

ical

cha

nge

s (i.

e.

turb

idity

, co

lour

, pH

and

alk

alin

ity)

and

bas

ed

on ja

r te

sts,

adj

ust t

reat

men

t in

resp

onse

to th

e ch

ang

es.

Con

side

r th

e u

se o

f str

eam

ing

curr

ent d

etec

tors

wh

ere

raw

wa

ter

qua

lity

can

vary

su

bst

antia

lly.

Use

of

wro

ng

chem

ical

s ca

n im

pair

trea

tme

nt

and

cont

amin

ate

prod

uct

wat

er.

Hea

lth o

r ae

sth

etic

impa

ct o

f che

mic

als.

C

lear

ly la

bel c

hem

ical

sup

ply

tank

s.

Ens

ure

that

the

del

iver

y of

che

mic

als

is s

upe

rvis

ed.

Tre

atm

ent c

hem

ical

s m

ay

be

of p

oor

qual

ity.

Poo

r pe

rfor

ma

nce

of c

oagu

latio

n, fl

occu

latio

n,

sedi

men

tatio

n re

sulti

ng in

ris

k of

illn

ess

from

the

in

ges

tion

of h

arm

ful m

icro

-org

anis

ms.

In

trod

uctio

n of

haz

ardo

us c

onta

min

ant

s in

to d

rinki

ng

wat

er.

Mak

e su

re th

at th

e ch

emic

al s

upp

lier

is c

ertif

ied

and

that

th

e ch

emic

als

do n

ot h

ave

cont

amin

ants

tha

t ex

ceed

gu

idel

ine

valu

es.

E

nsur

e th

at c

hem

ical

s ar

e su

pplie

d w

ith q

ua

lity

cert

ifica

tion.

E

nsur

e th

at d

eliv

ery

of c

hem

ical

s is

sup

ervi

sed.

41

Haz

ard

R

isk

Co

rre

ctiv

e ac

tio

n/s

FIL

TR

AT

ION

(E

.G.

RA

PID

, S

LO

W S

AN

D,

MU

LT

IME

DIA

)In

ade

quat

e re

mov

al o

f tur

bidi

ty (

and

part

icle

s) a

nd

harm

ful m

icro

-org

ani

sms

can

be c

ause

d b

y:

S

udd

en in

crea

se in

flo

w r

ate

Hyd

raul

ic s

hoc

k du

e to

sud

den

ope

n an

d cl

osin

g of

val

ves

In

com

plet

e or

insu

ffici

ent

back

wa

sh (

too

sho

rt,

rate

to lo

w,

air

scou

r in

ade

quat

e or

too

shor

t)

R

apid

sta

rt u

p fo

llow

ing

back

was

hing

Fai

lure

to

redu

ce f

low

rat

es d

urin

g ba

ckw

ash

ing

Med

ia d

isp

lace

men

t, cr

acki

ng o

r lo

ss

M

edia

blo

ckag

e in

clud

ing

mu

dba

lls

T

rapp

ing

of a

ir bu

bbl

es in

clud

ing

air

bin

din

g

Inab

ility

to p

rovi

de tr

eatm

ent

incr

ease

s th

e ri

sk o

f illn

ess

form

the

inge

stio

n of

har

mfu

l mic

ro-o

rgan

ism

s.

Poo

r ph

ysic

al q

ualit

y.

Incr

ease

d tu

rbid

ity a

nd o

rga

nic

mat

ter

can

inte

rfer

e w

ith

disi

nfec

tion

and

lea

d to

the

form

atio

n of

DB

Ps.

Mak

e su

re th

at p

lant

des

ign

is a

deq

uate

to s

upp

ort p

eak

loa

ds. D

o no

t ope

rate

filte

rs a

t ra

tes

that

exc

eed

des

ign

capa

city

. C

arry

out

rou

tine

mai

nten

ance

and

ca

libra

tion

of

mon

itori

ng s

yste

ms

and

ala

rms.

H

ave

proc

edur

es in

pla

ce fo

r au

tom

atic

bac

k-up

of

pow

er

or e

mer

genc

y sh

ut-d

ow

n/st

art-

up.

Avo

id s

udd

en c

han

ges

in fl

ow

rat

e in

clud

ing

duri

ng

oper

atio

n of

val

ves.

Mon

itor

bac

kwas

hing

to e

nsu

re b

ackw

ash

ra

tes

are

ade

quat

e

E

nsur

e ba

ckw

ash

times

are

suf

ficie

nt

E

ven

dist

ribu

tion

of a

ir sc

our

and

bac

kwa

sh f

low

s R

educ

e flo

w r

ate

s du

ring

back

wa

shin

g a

nd a

void

ra

pid

star

t-up

of f

ilter

s fo

llow

ing

bac

kwa

shin

g or

on

ret

urn

to

serv

ice.

If

poss

ible

, use

a fi

lter

wa

ste

faci

lity

to r

emov

e w

ate

r pr

oduc

ed d

urin

g be

d rip

eni

ng

(fol

low

ing

back

wa

sh).

U

nder

take

filte

r as

sess

men

ts.

Mon

itor

clea

n be

d h

eadl

oss.

P

OW

DE

RE

D/G

RA

NU

LA

R A

CT

IVA

TE

D C

AR

BO

NT

here

ma

y be

inad

equa

te r

emov

al o

f:

cy

ano

bact

eria

l (bl

ue-

gre

en a

lgae

) to

xins

Tas

te a

nd o

dour

com

poun

ds (

geos

min

an

d M

IB)

P

estic

ides

an

d or

gani

c co

mp

oun

ds

N

atur

ally

occ

urrin

g or

gan

ic m

atte

r, in

crea

sin

g tu

rbid

ity

Cya

nob

acte

rial t

oxin

s ca

n h

ave

serio

us h

eal

th e

ffect

s.

Tas

te a

nd o

dour

pro

ble

ms.

H

ealth

an

d ae

sthe

tic im

pact

of

chem

ica

ls.

Incr

ease

d tu

rbid

ity a

nd o

rga

nic

mat

ter

can

inte

rfer

e w

ith

disi

nfec

tion

and

lea

d to

the

form

atio

n of

DB

Ps

– ru

n ris

k of

illn

ess

from

bot

h.

Det

erm

ine

abso

rptiv

e ca

paci

ty o

f PA

C/G

AC

. U

se a

ppr

opri

ate

sour

ce o

f PA

C (

seek

exp

ert a

dvic

e).

CH

LO

RIN

AT

ION

(IN

CL

UD

ING

SE

CO

ND

AR

Y C

HL

OR

INA

TIO

N)

Dos

ing

mal

fun

ctio

n du

e to

eq

uipm

ent f

ailu

re o

r po

wer

fa

ilure

. P

ossi

ble

inte

rrup

tion

to c

hlor

inat

ion

(chl

orin

e un

der

dosi

ng,

chl

orin

e ov

erd

osi

ng).

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

O

verd

osin

g co

uld

caus

e:

Exp

osur

e to

ha

rmfu

l lev

els

of c

hlor

ine.

T

aste

and

odo

ur p

rob

lem

s.

Exp

osur

e to

pot

entia

lly h

arm

ful l

evel

s of

DB

Ps.

Use

con

tinu

ous

(ala

rme

d) m

oni

tori

ng o

f the

dos

ing

syst

em to

war

n o

f the

inte

rrup

tion

to c

hlor

inat

ion.

E

nsur

e a

utom

atic

shu

t-do

wn

if su

pply

of c

hlor

inat

ion

fails

. C

arry

out

rou

tine

perf

orm

ance

che

cks

and

mai

nte

nanc

e of

dos

ing

equi

pm

ent (

incl

. dos

ing

lines

, pum

ps

and

chlo

rine

cyl

ind

er c

han

geov

er s

yste

ms)

. R

egul

arly

cal

ibra

te d

osin

g e

qui

pmen

t an

d a

utom

atic

m

onito

ring

syst

ems.

H

ave

bac

k-up

po

we

r sy

stem

s or

acc

ess

to te

mpo

rary

do

sing

equ

ipm

ent.

Inst

all s

tand

by

dosi

ng e

quip

men

t inc

ludi

ng p

umps

.

42

Haz

ard

R

isk

Co

rre

ctiv

e ac

tio

n/s

Dis

infe

ctio

n ch

emic

al s

upp

ly r

uns

out.

Ill

ness

from

ing

estio

n of

har

mfu

l mic

ro-o

rga

nism

s.

Hav

e ro

utin

e p

roce

dur

es fo

r m

aint

ain

ing

fre

sh c

hlor

ine

stoc

ks a

nd o

n-si

te s

tora

ge o

f su

ffici

ent s

uppl

y.

Ens

ure

aut

oma

tic s

hut-

dow

n if

supp

ly o

f chl

orin

atio

n fa

ils.

Inst

all a

larm

s o

n ch

emic

al s

uppl

y ta

nks

or c

ylin

der

sc

ales

. C

arry

out

rou

tine

chec

ks o

f st

orag

e le

vels

. P

erfo

rm r

outin

e m

aint

ena

nce

of c

hlor

ine

cylin

der

chan

geov

er s

yste

ms.

C

hlor

ine

unde

rdos

ing

(inad

equa

te c

onta

ct ti

me)

ma

y oc

cur

due

to in

crea

sed

chlo

rin

e de

ma

nd in

ra

w w

ater

or

incr

ease

d w

ate

r flo

ws.

C

hang

es in

wa

ter

qual

ity c

oul

d be

sea

son

al o

r du

e to

ev

ents

suc

h as

hea

vy r

ain

or b

ush

fires

.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

In

stal

l flo

w p

ropo

rtio

nal d

osin

g to

acc

omm

oda

te

chan

ges

in fl

ow

or

resi

dua

l mon

itori

ng w

ith fe

edba

ck

cont

rol o

f chl

orin

e do

se r

ate

to a

ccom

mod

ate

bot

h ty

pes

of

fluc

tuat

ion.

If

raw

wa

ter

turb

idity

or

colo

ur c

han

ges

subs

tant

ially

, ch

eck

chlo

rine

dem

and

and

adj

ust d

ose

rate

if

nece

ssar

y.

C

hlor

ine

over

dos

ing

ma

y oc

cur

due

to d

ecre

ased

ch

lori

ne d

ema

nd in

ra

w w

ate

r or

dec

reas

ed w

ater

flo

ws.

Exp

osur

e to

ha

rmfu

l lev

els

of c

hlor

ine.

T

aste

s an

d od

our

pro

blem

s.

Exp

osur

e to

hig

h le

vels

of

DB

Ps.

Inst

all f

low

pro

port

iona

l dos

ing

to a

ccom

mo

date

ch

ange

s in

flo

w o

r re

sid

ual m

onito

ring

with

feed

back

co

ntro

l of c

hlor

ine

dose

rat

e to

acc

omm

odat

e b

oth

typ

es

of fl

uctu

atio

n.

Ra

w w

ater

turb

idity

/col

our

cha

nges

su

bsta

ntia

lly, c

heck

ch

lori

ne d

ema

nd a

nd

adju

st d

ose

rate

nec

ess

ary.

Lo

w fr

ee c

hlo

rine

res

idua

l in

the

dist

ribu

tion

syst

em

redu

ces

prot

ectio

n ag

ains

t fae

cal c

onta

min

atio

n an

d fr

ee

livin

g or

gan

ism

s.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

S

et d

osin

g to

pro

vid

e ad

equ

ate

conc

ent

ratio

n to

ach

ieve

in

itia

l dis

infe

ctio

n an

d w

her

e re

quire

d, fr

ee c

hlor

ine

resi

dua

ls w

ith th

e di

strib

utio

n sy

stem

. If

raw

wa

ter

turb

idity

or

colo

ur c

han

ges

subs

tant

ially

ch

eck

chlo

rine

dem

and

and

adj

ust d

ose

rate

if

nece

ssar

y.

Tre

atm

ent c

hem

ical

s m

ay

be

of p

oor

qual

ity

com

prom

isin

g ef

fect

iven

ess

of

disi

nfec

tion.

Ill

ness

from

ing

estio

n of

har

mfu

l mic

ro-o

rga

nism

s.

Intr

oduc

tion

of h

azar

dous

con

tam

ina

nts

into

the

wat

er.

Mak

e su

re th

at c

hem

ica

l sup

plie

r is

cer

tifie

d an

d th

at

chem

ical

s do

not

hav

e co

nta

min

ant

s th

at e

xcee

d gu

idel

ine

valu

es.

43

Haz

ard

R

isk

Co

rre

ctiv

e ac

tio

n/s

OZ

ON

AT

ION

Ozo

natio

n m

ay

be in

terr

upt

ed d

ue to

equ

ipm

ent

mal

func

tion,

exh

aust

ion

or p

ow

er

failu

re.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

U

se c

ontin

uou

s (a

larm

ed)

mo

nito

ring

of t

he d

osin

g sy

stem

to w

arn

of t

he in

terr

uptio

n to

ozo

natio

n.

Ens

ure

aut

oma

tic s

hut-

dow

n if

supp

ly o

f ozo

nat

ion

fails

. C

arry

out

rou

tine

perf

orm

ance

che

cks

and

mai

nte

nanc

e of

dos

ing

equi

pm

ent i

ncl.

pum

ps.

Reg

ular

ly c

alib

rate

dos

ing

eq

uipm

ent a

nd

aut

omat

ic

mon

itorin

g sy

stem

s.

Hav

e b

ack-

up p

ow

er

syst

ems

or a

cces

s to

tem

pora

ry

dosi

ng e

quip

men

t. In

crea

sed

wat

er

flow

s ca

n le

ad

to u

nder

dos

ing

(ina

deq

uate

co

ntac

t tim

e).

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

M

onito

r re

sidu

al o

zone

leve

ls a

t out

let o

f con

tact

tank

w

ith a

larm

to w

arn

if re

sid

uals

not

det

ecta

ble.

R

egul

arly

cal

ibra

te a

utom

atic

mon

itorin

g sy

stem

s.

Mon

itor

flow

ra

tes

and

adj

ust

dose

rat

es a

s re

quire

d.

Hig

h pH

(>

8) o

r hi

gh tu

rbid

ity c

an r

esu

lt in

un

derd

osin

g.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

O

n-lin

e m

onito

ring

of p

H,

turb

idity

, co

lour

and

flo

w r

ate

with

ala

rm to

war

n if

oper

atio

nal

lim

its a

re e

xcee

ded

. U

se p

re-f

iltra

tion

to r

educ

e tu

rbid

ity b

elo

w 1

NT

U a

nd

pre-

trea

tme

nt to

red

uce

natu

ral o

rgan

ic m

atte

r.

Bro

mid

e m

ay

be

pres

ent

in r

aw

wat

er.

Exc

essi

ve fo

rmat

ion

of b

rom

inat

ed D

BP

s.

Adj

ust

wat

er a

lkal

inity

to r

edu

ce b

rom

ate

form

atio

n.

Mak

e su

re th

at o

zone

is u

sed

with

in p

re-s

et d

oses

. U

LT

RA

VIO

LE

T R

AD

IAT

ION

D

isin

fect

ion

ma

y be

inte

rrup

ted

by

equi

pme

nt

mal

func

tion

or p

ow

er

failu

re.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

U

se c

ontin

uou

s (a

larm

ed)

mo

nito

ring

of t

he U

V

oper

atio

n an

d tr

ansm

itted

dos

e.

Car

ry o

ut r

outin

e m

aint

enan

ce in

cl. c

lean

ing

of U

V

lam

ps/s

leev

es a

nd r

epl

acem

ent

of U

V la

mps

at t

he e

nd

of th

eir

exp

ecte

d lif

e.

Reg

ular

ly in

spec

t UV

sys

tem

and

re

plac

e bu

rnt o

ut

lam

ps.

Reg

ular

ly c

alib

rate

aut

omat

ic m

onito

ring

syst

ems.

H

ave

bac

k-up

po

we

r sy

stem

s av

aila

ble.

In

ade

quat

e irr

adi

atio

n (d

isin

fect

ion)

ma

y be

due

to

incr

eas

ed tu

rbid

ity o

r co

lour

in r

aw

wat

er o

r in

crea

sed

flow

s.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

U

se p

re-f

iltra

tion

to r

educ

e tu

rbid

ity to

be

low

1 N

TU

O

pera

te fl

ow

rat

es to

with

in t

he U

V li

ght s

yste

m.

SO

FT

EN

ING

Sof

tene

d w

ate

r ca

n be

cor

rosi

ve a

nd le

ach

chem

ical

s fr

om p

ipes

. H

ealth

or

aest

het

ic im

pact

of c

hem

ical

s, e

.g. c

oppe

r.

Mix

sof

tene

d w

ater

with

ble

ndi

ng w

ater

s (u

nsof

tene

d w

ater

) or

rec

arbo

nat

e th

e w

ater

to r

educ

e co

rros

iven

ess.

S

ofte

nin

g of

ve

ry h

ard

wat

ers

usin

g io

n e

xch

ang

e ca

n le

ad

to in

cre

ased

con

cent

ratio

ns o

f sod

ium

in th

e w

ater

. U

nacc

epta

ble

tast

es.

Mix

sof

tene

d w

ater

with

ble

ndi

ng w

ater

s (u

nsof

tene

d w

ater

) or

rec

arbo

nat

e th

e w

ater

to r

educ

e un

acce

pta

ble

tast

es.

44

Haz

ard

R

isk

Co

rre

ctiv

e ac

tio

n/s

Whe

re li

me

softe

nin

g is

use

d in

corr

ect d

osin

g or

poo

r pH

con

tro

l can

red

uce

the

effic

ienc

y of

the

proc

ess

and

ma

y in

terf

ere

with

oth

er tr

eatm

ent p

roce

sse

s (e

.g. i

f us

ed in

con

jun

ctio

n w

ith c

oag

ulat

ion,

floc

cula

tion

and

se

dim

enta

tion)

.

Incr

ease

d ha

rdne

ss.

Pos

t sof

teni

ng

prec

ipita

tion

of e

xces

s lim

e an

d fo

rmat

ion

of c

alci

um c

arb

onat

e d

epos

its.

Inte

rfer

ence

with

coa

gula

tion,

floc

cula

tion

and

sedi

men

tatio

n ca

n re

duc

e th

e r

emov

al o

f har

mfu

l mic

ro-

orga

nism

s, le

ad

to p

oor

ph

ysic

al q

ual

ity (

e.g.

turb

idity

) an

d in

terf

ere

with

dis

infe

ctio

n.

Mon

itor

dos

e ra

tes

of li

me.

M

onito

r p

H s

ofte

ning

pro

cess

. M

ake

sure

that

suf

ficie

nt c

hem

ical

sto

cks

are

mai

nta

ine

d.

Est

ablis

h a

pro

cedu

re fo

r re

gula

r ch

ecki

ng o

f st

orag

e ta

nk le

vels

. H

ave

ala

rms

in th

e ch

emic

al s

upp

ly ta

nks

to in

dica

te

wh

en

tank

s ar

e lo

w.

Whe

re li

me

softe

nin

g is

use

d, tr

eatm

ent c

hem

ical

s m

ay

be o

f po

or q

ualit

y.

Intr

oduc

tion

of h

azar

dous

che

mic

als

into

ra

w w

ater

. M

ake

sure

that

che

mic

al s

upp

lier

is c

ertif

ied

and

the

chem

ical

s do

not

hav

e co

nta

min

ant

s th

at e

xcee

d gu

idel

ine

valu

es.

O

rgan

ic m

ater

ial m

ay

accu

mu

late

in r

esin

s (w

her

e us

ed)

and

supp

ort m

icro

bial

gro

wth

. P

oor

trea

tmen

t ef

ficie

ncy.

T

aste

and

odo

ur p

rob

lem

s.

Pre

-tre

at w

ate

r to

rem

ove

org

anic

mat

ter

befo

re

softe

ning

. K

eep

ma

inte

nanc

e up

-to-

date

, in

clu

din

g re

ge

nera

tion

of

resi

n.

Sou

rce

wat

er v

ery

har

d (>

200

mg

calc

ium

car

bon

ate)

. S

cale

bui

ld-u

p on

trea

tmen

t equ

ipm

ent a

nd p

ipin

g.

Kee

p w

ater

sof

teni

ng

equi

pmen

t w

ell m

aint

ain

ed

and

rem

ove

scal

e if

nece

ssar

y.

PR

OT

EC

TE

D S

ER

VIC

E R

ES

ER

VO

IR (

CO

VE

RE

D S

TO

RA

GE

TA

NK

)A

nim

als/

bird

s ca

n en

ter

thro

ugh

faul

ts a

nd

cont

amin

ate

the

wat

er w

ith t

heir

drop

pin

gs.

If an

imal

s dr

ow

n, th

ere

will

be

a hi

ghe

r le

vel o

f ha

rmfu

l m

icro

-org

anis

ms

pres

ent.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

P

ossi

ble

od

ours

. C

heck

tank

ro

of

regu

larl

y fo

r h

oles

and

dam

age

. M

ake

sure

all

ope

nin

gs a

nd o

verf

low

s ar

e sc

reen

ed/s

eal

ed.

M

aint

ain

dis

infe

ctan

t res

idua

l with

in th

e ta

nk.

Ani

mal

/bird

dro

ppin

gs m

ay

be

wa

shed

into

sto

rag

es in

ra

inw

ate

r, e

nte

ring

thro

ugh

faul

ts in

the

stor

age

roo

f or

from

inte

rna

lly d

rain

ing

roof

s.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

Che

ck r

oof

of t

ank

reg

ular

ly f

or h

oles

an

d d

amag

e.

Pre

vent

inte

rna

l dra

inag

e fr

om th

e ro

of in

to th

e ta

nk.

Mai

nta

in d

isin

fect

ant r

esid

ual i

nsid

e th

e ta

nk.

Una

utho

rised

hum

an a

cces

s, s

uch

as s

wim

min

g in

the

stor

age

tank

s, c

an c

ause

mic

robi

al c

onta

min

atio

n

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

M

ake

sure

that

all

fenc

es, t

ow

ers

and

roof

ha

tche

s ar

e al

wa

ys lo

cke

d.

Mai

nta

in d

isin

fect

ant r

esid

ual w

ithin

the

tank

. H

igh

chlo

rine

leve

ls m

ay

ent

er

the

dist

ribut

ion

syst

em if

th

ere

is p

oor

mix

ing

afte

r di

sin

fect

ion

of s

tora

ges.

Ir

ritat

ion

of m

ucou

s m

embr

anes

. T

aste

and

odo

ur p

rob

lem

s.

Whe

n di

sinf

ectin

g st

orag

es, m

ake

sure

that

ther

e is

ad

equ

ate

mix

ing.

M

easu

re fr

ee c

hlor

ine

resi

dual

s in

the

stor

age

outle

t fo

llow

ing

chlo

rina

tion.

R

e-su

spen

sio

n o

f sed

imen

ts c

onta

inin

g sl

ime

s an

d od

our

pro

duci

ng

mic

ro-o

rgan

ism

s m

ay

occu

r.

Odo

urs.

In

crea

sed

turb

idity

and

re

duct

ion

of d

isin

fect

ant

res

idu

al.

Min

imiz

eent

ry o

f dus

t. In

spec

t sto

rag

es r

egu

larly

an

d cl

ean

wh

en n

eces

sary

. V

and

alis

m o

r sa

bota

ge m

ay

pol

lute

the

wat

er w

ith

chem

ical

s or

mic

rob

es o

r da

mag

e e

quip

me

nt a

nd

infr

astr

uctu

re.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

H

ealth

or

aest

het

ic im

pact

of c

hem

ical

s.

Inte

rrup

tion

of s

upp

ly.

Mak

e su

re a

ll fe

nces

, to

wer

s, la

dde

rs a

nd

roof

hat

ches

ar

e al

wa

ys lo

cked

. R

epai

r an

y d

am

ages

to s

ecu

rity

devi

ces.

If

vand

alis

m o

r sa

bota

ge is

su

spec

ted,

take

sto

rage

out

of

ser

vice

unt

il in

vest

igat

ions

are

com

ple

te a

nd s

amp

ling

indi

cate

s th

at w

ater

is s

afe.

45

Haz

ard

R

isk

Co

rre

ctiv

e ac

tio

n/s

UN

PR

OT

EC

TE

D S

ER

VIC

E R

ES

ER

VO

IR (

UN

CO

VE

RE

D S

TO

RA

GE

TA

NK

)A

nim

als/

bird

s ca

n en

ter

thro

ugh

faul

ts a

nd

cont

amin

ate

the

wat

er w

ith t

heir

drop

pin

gs.

If an

imal

s dr

ow

n, th

ere

will

be

a hi

ghe

r le

vel o

f ha

rmfu

l m

icro

-org

anis

ms

pres

ent.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

P

ossi

ble

od

ours

. P

rovi

de

fenc

ing

to r

educ

e an

imal

acc

ess.

C

heck

tank

re

gul

arly

for

dea

d an

imal

s an

d de

bris

. M

aint

ain

dis

infe

ctan

t res

idua

l with

in th

e ta

nk.

Con

side

r us

ing

dis

infe

ctio

n if

not a

lread

y d

one

. A

nim

al/b

ird d

ropp

ings

ma

y b

e w

ash

ed in

to s

tora

ges

in

rain

wa

ter,

ent

erin

g th

roug

h fa

ults

in th

e st

ora

ge r

oof o

r fr

om in

tern

ally

dra

inin

g ro

ofs.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

M

ake

sure

that

all

fenc

es, t

ow

ers,

ladd

ers

and

roof

ha

tche

s ar

e al

wa

ys lo

cked

. C

onsi

der

usin

g d

isin

fect

ion

if no

t alre

ady

do

ne.

Mai

nta

in d

isin

fect

ant r

esid

ual w

ithin

the

tank

. G

row

th o

f cya

nob

acte

ria

(blu

e-g

ree

n al

gae

) a

nd o

ther

al

gae

ca

n be

a p

robl

em w

here

sto

rage

tank

s ar

e op

en

to

sunl

ight

.

Som

e sp

ecie

s of

cya

nob

acte

ria

prod

uce

toxi

ns th

at h

ave

serio

us h

ealth

effe

cts.

T

aste

and

odo

ur p

rob

lem

s fr

om

cya

nob

acte

ria.

Mai

nta

in d

isin

fect

ant r

esid

ual w

ithin

the

tank

. C

onsi

der

usin

g d

isin

fect

ion

if no

t alre

ady

do

ne.

Spr

ay

drift

s fr

om n

earb

y fa

rmin

g ac

tiviti

es in

cl.

pest

icid

es a

nd a

gric

ultu

ral c

hem

ical

s as

we

ll as

dirt

and

ot

her

win

d b

orne

de

bris

ca

n en

ter

stor

age.

Ph

ysic

al c

onta

min

atio

n of

the

wat

er.

Hea

lth im

pact

s of

che

mic

als.

C

heck

tank

re

gul

arly

for

deb

ris.

Wor

k w

ith lo

cal c

omm

unity

to

man

age

aer

ial s

pra

ying

ac

tiviti

es s

o as

to

avoi

d co

nta

min

atio

n of

rai

nw

ater

tank

s.

Bus

hfire

ma

y le

ad to

ret

arda

nts

and

larg

e a

mou

nts

of

ash

ente

rin

g st

orag

e.

Tas

te a

nd o

dour

pro

ble

ms.

H

ealth

an

d ae

sthe

tic im

pact

of

chem

ica

ls.

Poo

r ph

ysic

al q

ualit

y of

wat

er.

Che

ck ta

nk r

eg

ular

ly fo

r d

ebris

. If

nece

ssar

y, fl

ush

and

cle

an ta

nk a

fter

a bu

shfir

e.

Hig

h ch

lori

ne r

esid

uals

ma

y e

nter

the

dist

ribut

ion

syst

em

if th

ere

is p

oor

mix

ing

afte

r di

sinf

ectio

n in

sto

rage

s.

Irrit

atio

n of

muc

ous

mem

bran

es.

Tas

te a

nd o

dour

pro

ble

ms.

W

hen

disi

nfec

ting

stor

ages

, mak

e su

re th

at th

ere

is

ade

quat

e m

ixin

g.

Mea

sure

free

chl

orin

e re

sidu

als

in th

e st

orag

e ou

tlet

follo

win

g ch

lori

natio

n.

Re-

susp

ensi

on

of s

edim

ents

con

tain

ing

slim

es

and

odo

ur p

rodu

cin

g m

icro

-org

anis

ms

ma

y oc

cur.

O

dour

s.

Incr

ease

d tu

rbid

ity a

nd r

edu

ctio

n of

dis

infe

cta

nt r

esid

ual

. M

inim

izee

ntry

of d

ust.

Insp

ect s

tora

ges

reg

ula

rly a

nd

clea

n w

hen

nec

essa

ry.

Van

dal

ism

or

sabo

tage

ma

y p

ollu

te th

e w

ater

with

ch

emic

als

or m

icro

bes

or

dam

age

equ

ipm

ent

and

in

fras

truc

ture

.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

H

ealth

or

aest

het

ic im

pact

of c

hem

ical

s.

Inte

rrup

tion

of s

upp

ly.

Mak

e su

re a

ll fe

nces

, to

wer

s, la

dde

rs a

nd

roof

hat

ches

ar

e al

wa

ys lo

cked

. R

epai

r an

y d

am

ages

to s

ecu

rity

devi

ces.

If

vand

alis

m o

r sa

bota

ge is

su

spec

ted,

take

sto

rage

out

of

ser

vice

unt

il in

vest

igat

ions

are

com

ple

te a

nd s

amp

ling

indi

cate

s th

at w

ater

is s

afe.

46

Haz

ard

R

isk

Co

rre

ctiv

e ac

tio

n/s

DIS

TR

IBU

TIO

N S

YS

TE

M

Pip

e b

urst

s an

d le

aks

can

inte

rrup

t the

wat

er

supp

ly.

Con

tam

inat

ion

can

occu

r w

her

e w

ate

r pi

pes

are

bel

ow

or

clo

se to

sto

rm w

ater

or

sew

age

pip

es o

r in

are

as w

ith

sept

ic ta

nks,

lead

ing

to m

icro

bial

and

che

mic

al

cont

amin

atio

n.

Ent

ry o

f so

il m

ay in

crea

se tu

rbid

ity.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

A

esth

etic

pro

blem

s as

soci

ate

d w

ith tu

rbid

ity.

Loss

of

wat

er.

Inte

rrup

tion

to s

upp

ly.

Est

ablis

h pr

even

tativ

e m

ain

tena

nce

pro

gram

me

to

redu

ce li

kelih

ood

of p

ipe

burs

ts o

r va

lve

failu

res.

K

eep

inva

sive

tree

s a

wa

y fr

om

pip

es.

Est

ablis

h re

spon

se a

nd r

epa

ir p

roce

dur

es to

m

inim

izet

he ti

me

take

n to

iso

late

a p

ipe

bur

st.

Use

diff

ere

nt c

olo

ured

pip

e-w

ork

for

pota

ble

and

non

-po

tab

le w

ater

and

ma

inta

in lo

we

r pr

essu

res

in n

on-

pota

ble

su

pplie

s th

an in

pot

able

sup

plie

s.

Mai

nta

in s

epar

atio

n d

ista

nces

from

se

wa

ge/s

torm

wat

er

syst

ems.

P

rovi

de

suita

ble

pro

tect

ion

for

pipe

s in

dra

ina

ge o

r riv

er

cros

sin

gs. I

sola

te th

ese

cros

sing

s d

urin

g flo

odi

ng.

M

icro

bial

or

chem

ical

con

tam

inan

ts c

an e

nte

r th

e w

ater

su

pply

sys

tem

thr

oug

h cr

oss-

conn

ectio

ns o

r ba

ckflo

w.

Illne

ss fr

om th

e in

gest

ion

of h

arm

ful m

icro

-org

anis

ms.

H

ealth

or

aest

het

ic im

pact

of c

hem

ical

s.

Pre

vent

bac

kflo

w –

inst

all

back

flow

pre

vent

ion

devi

ces.

A

void

cro

ss-c

onn

ectio

ns b

etw

een

drin

king

wat

er a

nd

othe

r w

ater

an

d flu

id s

yste

ms.

M

aint

ain

pos

itive

pre

ssur

e in

the

dis

trib

utio

n sy

stem

. W

ater

can

be

cont

amin

ate

d d

urin

g re

pair

and

mai

nte

nanc

e.

Ent

ry o

f so

il ca

n in

crea

se tu

rbid

ity.

Illne

ss fr

om th

e in

gest

ion

of h

arm

ful m

icro

-org

anis

ms.

A

esth

etic

pro

blem

s as

soci

ate

d w

ith tu

rbid

ity.

Est

ablis

h pr

oced

ures

for

mai

nten

anc

e a

nd r

epa

ir th

at

min

imiz

ethe

like

lihoo

d of

con

tam

inat

ion.

A

fter

repa

ir, fl

ush

thor

ough

ly a

nd w

her

e ne

cess

ary,

ch

lori

nate

the

pip

es.

Inad

equ

ate

disi

nfec

tion

or fl

ushi

ng

befo

re

com

mis

sio

ning

of n

ew

mai

ns r

esul

ts in

co

nta

min

atio

n –

chem

ical

an

d m

icro

bial

co

nta

min

atio

n.

Pre

senc

e of

so

il ca

n in

crea

se tu

rbid

ity.

Illne

ss fr

om th

e in

gest

ion

of h

arm

ful m

icro

-org

anis

ms.

H

ealth

an

d ae

sthe

tic im

pact

of

chem

ica

l con

tam

inan

ts.

Aes

thet

ic p

robl

ems

asso

ciat

ed

with

turb

idity

.

Est

ablis

h st

and

ard

proc

edur

es fo

r co

mm

issi

oni

ng

new

m

ains

, inc

lud

ing

disi

nfec

tion

and

flus

hin

g.

Sto

re n

ew

pip

es

and

fittin

gs w

ith o

peni

ngs

seal

ed.

Con

tam

inat

ed

wat

er m

ay

ente

r th

e sy

stem

dur

ing

flood

ing,

par

ticul

arly

thro

ugh

abov

e gr

oun

d h

ydra

nts

and

air

valv

es. M

icro

bial

an

d ch

emic

al c

ont

amin

atio

n po

ssib

le

Pre

senc

e of

so

il m

ay

incr

eas

e tu

rbid

ity.

Illne

ss fr

om th

e in

gest

ion

of h

arm

ful m

icro

-org

anis

ms.

H

ealth

an

d ae

sthe

tic im

pact

of

chem

ica

l con

tam

inan

ts.

Aes

thet

ic p

robl

ems

asso

ciat

ed

with

turb

idity

.

Pro

tect

pip

es in

dra

inag

e an

d r

iver

cro

ssin

gs.

Isol

ate

dra

inag

e or

riv

er c

ross

ing

dur

ing

floo

din

g.

If co

ntam

inat

ed

by

flood

wa

ter,

flus

h pi

pes

thor

ough

ly

and

wh

ere

poss

ible

, ch

lorin

ate.

Rai

sed

tem

pera

ture

s (e

.g. 2

5-30

oC

) in

long

, ab

ove

grou

nd p

ipe

lines

can

sup

port

the

gro

wth

of s

ome

orga

nism

s.

Ser

ious

illn

ess

thro

ugh

inha

latio

n or

co

ntac

t. C

onsi

der

usin

g c

hlor

amin

atio

n to

pro

vide

a p

ersi

sten

t re

sid

ual.

Leac

hin

g fr

om c

emen

t pip

es, p

artic

ula

rly

dur

ing

peri

ods

of lo

w fl

ow

, ca

n ca

use

a hi

gh

pH.

Ver

y hi

gh

pH (

>10

) ca

n da

ma

ge h

ous

eho

ld p

lum

bin

g

pH >

11

can

irrita

te e

yes

and

skin

. F

lush

pip

es d

urin

g p

erio

ds o

f ver

y lo

w fl

ow

In

vest

igat

e w

ays

to in

crea

se f

low

s th

roug

h se

ctio

ns o

f th

e pi

pe.

C

hang

es in

flo

w o

r in

cre

ased

con

cent

ratio

ns o

f di

sinf

ecta

nt c

an

caus

e sl

ough

ing

and

re-

susp

ensi

on o

f bi

ofilm

s.

Incr

ease

d tu

rbid

ity.

Dis

colo

ured

wat

er.

Tas

te a

nd o

dour

pro

ble

ms.

Flu

sh m

ains

be

fore

cha

nge

s in

flo

w o

r in

crea

sed

conc

ent

ratio

ns o

f dis

infe

cta

nt c

ould

lea

d to

slo

ughi

ng

of

biof

ilms.

P

ump

failu

re

Inte

rrup

tion

to s

upp

ly.

Hav

e b

ack-

up s

yste

ms

avai

labl

e fo

r pu

mpi

ng

faci

litie

s (a

ltern

ativ

e po

we

r su

ppl

y an

d s

pare

pum

ps).

47

Haz

ard

R

isk

Co

rre

ctiv

e ac

tio

n/s

Dea

d-en

d m

ains

and

low

wat

er fl

ow

s ca

n le

ad to

st

agna

nt w

ate

r an

d lo

ss o

f res

idu

al c

hlor

ine.

U

nacc

epta

ble

odo

urs.

In

vest

igat

e w

ays

to in

crea

se f

low

s th

roug

h se

ctio

ns o

f th

e pi

pe.

R

educ

e d

ead

end

s U

nsui

tabl

e co

atin

gs a

nd

mat

eria

ls c

an

leac

h ch

emic

als

or s

upp

ort b

acte

rial g

row

th.

Hea

lth o

r ae

sth

etic

impa

ct o

f che

mic

als.

T

aste

and

odo

ur p

rob

lem

s.

Use

on

ly m

ater

ials

app

rove

d fo

r us

e in

dri

nkin

g w

ater

.

Van

dal

ism

or

sabo

tage

ma

y p

ollu

te th

e w

ater

with

ch

emic

als

or m

icro

bes

or

dam

age

equ

ipm

ent

and

in

fras

truc

ture

.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

H

ealth

or

aest

het

ic im

pact

of c

hem

ical

s.

Inte

rrup

tion

to s

upp

ly.

Mak

e su

re th

at p

oten

tially

acc

essi

ble

com

po

nent

s of

di

strib

utio

n sy

stem

s ar

e ke

pt s

ecur

e a

nd a

re lo

cked

.

HO

US

EH

OL

D C

ON

NE

CT

ION

S

Hou

seho

ld p

lum

bin

g ca

n:

Leac

h ch

emic

als

that

hav

e h

eal

th im

pac

ts o

r ca

use

tast

es a

nd o

dour

s.

Sup

por

t mic

rob

ial g

row

th th

at c

an a

lso

caus

e ta

stes

and

od

our

s.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

H

ealth

or

aest

het

ic im

pact

of c

hem

ical

s.

Edu

cate

hou

seho

lder

s an

d pl

umbe

rs a

bout

saf

e pl

umbi

ng

mat

eria

ls a

nd in

sta

llatio

n.

Hou

seho

ld p

lum

bin

g ca

n b

ecom

e co

rro

ded

thro

ugh

in

corr

ect i

nsta

llatio

n or

from

act

ion

of w

ater

sup

ply

on

fittin

gs.

Hea

lth o

r ae

sth

etic

impa

ct o

f che

mic

als

Edu

cate

hou

seho

lder

s an

d pl

umbe

rs a

bout

saf

e pl

umbi

ng

mat

eria

ls a

nd in

sta

llatio

n.

Bac

kflo

w fr

om h

ouse

hol

d p

lum

bin

g de

vice

s or

wat

er

stor

ages

(e.

g. r

ain

wa

ter

tank

s, s

wim

min

g p

ools

, gar

den

pon

ds)

can

cont

amin

ate

drin

king

wat

er s

yste

ms.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

H

ealth

or

aest

het

ic im

pact

of c

hem

ical

s.

Inst

all b

ack-

flow

pre

vent

ion

devi

ces.

48

H

azar

d

Ris

kC

orr

ect

ive

acti

on

/sC

OM

MU

NIT

Y S

TA

ND

PIP

ES

B

ackf

low

from

tan

kers

con

nect

ing

to s

tand

pip

es c

an

lea

d to

mic

robi

al a

nd

chem

ica

l con

tam

inat

ion

of t

he

wat

er.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

H

ealth

or

aest

het

ic im

pact

of c

hem

ical

s.

Mak

e su

re th

at th

ere

is e

noug

h po

sitiv

e pr

essu

re a

t the

fil

ling

poin

t to

redu

ce p

ote

ntia

l bac

kflo

w.

Inst

all b

ackf

low

pre

vent

ion

valv

es.

Wat

er s

tand

ing

at a

cces

s po

ints

can

attr

act b

irds

and

anim

als,

rai

sin

g ve

ctor

and

dis

ease

co

ncer

ns.

Ill

ness

from

ing

estio

n of

har

mfu

l mic

ro-o

rga

nism

s.

M

ake

sure

that

taps

are

sel

f clo

sin

g to

min

imiz

ew

ater

lo

ss.

Scr

een

end

of

stan

dpip

es to

pre

vent

the

ent

ry o

f bir

ds,

inse

cts,

etc

.

Ere

ct fe

ncin

g a

roun

d th

e fil

ling

poi

nt to

con

tro

l acc

ess

of

cattl

e, e

tc.

Mak

e su

re a

rea

arou

nd th

e fil

ling

poin

t has

goo

d dr

aina

ge.

R

egul

arly

cle

an/

disi

nfec

t the

tap/

stan

dpi

pe e

nd.

Dam

age

to th

e fi

lling

poi

nt c

an in

terr

upt

sup

ply

and

allo

w

entr

y of

con

tam

inat

ion.

Ill

ness

from

ing

estio

n of

har

mfu

l mic

ro-o

rga

nism

s.

Hea

lth o

r ae

sth

etic

impa

ct o

f che

mic

als.

P

ossi

ble

inte

rrup

tion

to s

upp

ly.

Inst

all c

over

s to

pro

tect

the

taps

.

Con

tain

ers

use

d to

col

lect

and

tran

spor

t the

wat

er m

ay

be c

onta

min

ated

. Ill

ness

from

ing

estio

n of

har

mfu

l mic

ro-o

rga

nism

s.

Hea

lth o

r ae

sth

etic

impa

ct o

f che

mic

als.

E

duca

te th

e pu

blic

re

gard

ing

the

sele

ctio

n an

d ca

re o

f co

ntai

ners

and

pro

tect

ion

of w

ater

follo

win

g co

llect

ion.

S

pilla

ge

of c

hem

ical

s (e

.g. f

uel/d

eter

gen

ts fr

om

leak

ing

cont

aine

rs)

in p

roxi

mity

of t

he s

tand

pipe

ca

n ca

use

cont

amin

atio

n.

Hea

lth o

r ae

sth

etic

impa

ct o

f che

mic

als.

P

ut u

p si

gns

for

appr

opr

iate

car

e an

d us

age

of t

he

com

mun

ity s

tand

pip

e.

Con

duct

ed

uca

tion

pro

gram

s re

gard

ing

the

care

of t

he

com

mun

ity s

tand

pip

e.

RA

IN W

AT

ER

HA

RV

ES

TIN

G

Roo

f pa

int c

onta

ins

chem

ica

l con

tam

inan

ts.

Hea

lth o

r ae

sth

etic

impa

ct o

f che

mic

als.

R

oof p

ain

t mus

t be

sui

tabl

e fo

r po

tabl

e w

ater

, i.e

. it m

ust

not c

onta

in a

ny

lead

. F

olia

ge c

olle

ctio

n ov

er/a

long

gut

ters

and

roo

ftops

. A

esth

etic

imp

act

from

folia

ge.

Dec

ayi

ng d

ebri

s ca

n le

ad

to h

ealth

impa

cts.

F

olia

ge m

ust b

e cl

eare

d re

gula

rly.

D

isin

fect

ion

prio

r to

con

sum

ptio

n.

Bird

/an

imal

dro

ppin

gs c

ont

amin

ate

wat

er.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

G

utte

rs a

nd c

olle

ctio

n ta

nk c

ove

r m

ust b

e w

ell

prot

ecte

d.

Dis

infe

ctio

n pr

ior

to c

onsu

mpt

ion.

F

irst f

lush

of

wat

er c

an e

nter

sto

rage

tank

. H

ealth

or

aest

het

ic im

pact

fro

m w

hat

ever

du

st/d

ebris

th

at m

ight

hav

e co

llect

ed in

the

gutte

rs/p

ipe

. In

stal

l a fi

rst-

flush

div

ersi

on u

nit.

49

H

azar

d

Ris

kC

orr

ect

ive

acti

on

/sH

OU

SE

HO

LD

TR

EA

TM

EN

T

Chl

orin

e un

der

dosi

ng.

Ill

ness

from

ing

estio

n of

har

mfu

l mic

ro-o

rga

nism

s.

Com

mun

ity a

war

enes

s pr

ogr

am

mes

and

de

mon

stra

tions

on

ho

w to

con

duc

t hou

seho

ld d

isin

fect

ion.

C

hlor

ine

over

dos

ing.

E

xpos

ure

to h

arm

ful l

evel

s of

chl

orin

e ca

n ca

use

illne

ss.

Tas

te a

nd o

dour

pro

ble

ms.

C

omm

unity

aw

aren

ess

pro

gra

mm

es a

nd d

em

onst

ratio

ns

on h

ow

to c

ond

uct h

ouse

hold

dis

infe

ctio

n.

Re-

cont

amin

atio

n of

wat

er d

ue

to s

tora

ge in

ope

n co

ntai

ners

that

ma

y b

e ac

cess

ible

to b

irds/

ani

mal

s.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

A

esth

etic

imp

act

on

wat

er.

Sec

ure

cont

ain

ers

with

sea

led

lids

to a

void

co

ntam

inat

ion

from

bird

s/a

nim

als.

R

e-co

ntam

inat

ion

due

to u

nhyg

ieni

c pr

actic

es

wh

en

han

dlin

g/dr

aw

ing

wat

er fr

om th

e st

orag

e co

nta

iner

.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

A

esth

etic

impa

ct t

o w

ater

. C

omm

unity

aw

aren

ess

pro

gra

mm

es a

nd d

em

onst

ratio

ns

on h

ow

to m

ain

tain

hyg

iene

whe

n h

andl

ing/

dra

win

g w

ater

from

the

stor

age

cont

aine

r.

Re-

cont

amin

atio

n du

e to

use

of i

mpr

oper

sto

rage

co

ntai

ner,

e.g

. met

al d

rum

s, a

nd th

e co

ntai

ner

not

bei

ng

mai

nta

ine

d in

a c

lean

co

nditi

on.

Illne

ss fr

om in

ges

tion

of h

arm

ful m

icro

-org

ani

sms.

A

esth

etic

imp

act

on

wat

er.

Avo

id u

sing

met

al d

rum

s/co

nta

iner

s to

col

lect

and

trea

t w

ater

. Use

pla

stic

con

tain

ers

only

. W

ash

stor

age

cont

aine

rs r

egul

arly

; pre

fera

bly

bef

ore

new

wat

er is

bei

ng

dra

wn

befo

re d

isin

fect

ion

.