For residents and installers in Golden Plains Shire

Your guide to

Septic Tank Applications

31/05/17 Page 2

About septic tank permits

Under the Environment Protection Act 1970, any person requires a permit from Council to

construct, install or alter any part of a septic tank system. Legal penalties apply for work carried

out without a permit.

The permit consists of a two stage process:

1. A ‘Permit to Alter/Install’ a septic tank system. This permit must be issued before a

building permit can be issued.

2. A ‘Certificate to Use’ the septic tank system. This permit must be issued before a

building Certificate of Occupancy can be issued.

Contact us

Call Golden Plains Shire Customer Service Visit our Bannockburn Office

Phone: (03) 5220 7111

Local call: 1300 36 30 36

Fax: (03) 5220 7100

2 Pope Street

Bannockburn Victoria 3331

Postal Address Visit our Linton Office

Golden Plains Shire Council

PO Box 111

Bannockburn Victoria 3331

enquiries@gplains.vic.gov.au

68 Sussex Street

Linton Victoria 3360

31/05/17 Page 3

Do you need a permit?

When considering whether a Permit to Install or Alter is required, please refer to the following

tables:

Application to install a septic tank system

Installing a new system

Replacement of an existing system

Upgrade of an existing system to a system of a different type, such as:

o Upgrade from a split system to an all waste system

o Upgrade from a primary treatment system to a secondary treatment system

Application to alter a septic tank system

Replacement or relocation of one part of an existing system such as:

o Relocation of absorption trenches

o Relocation of irrigation lines

o Upgrade of an effluent disposal area

o Dwelling extensions where there is an

addition of wastewater generating fixtures,

fittings or appliances

o Dwelling extensions where the number of

habitable rooms is increased. Habitable rooms

include any room that may be closed off with a

door, such as a study, library or sunroom that

could be used for the purposes of a bedroom.

o Change of use of a property i.e. from a dwelling

to a shop where installation or replacement of

the system is not required.

You may choose to submit applications directly, or your plumber/drainer may submit an application

on your behalf. Either way remember that you as the owner must sign the application form.

i Note: if during the

application process for an alteration it is identified that

the alterations required meet the definitions for an

installation, then the application will be considered a new

installation.

31/05/17 Page 4

All septic tank applications (installation and alteration) require the following:

1 Completed and signed application form

2 House/Building Floor Plan (detailing all rooms and plumbing fixtures)

3 Site Plan (refer to Site Plan section of this document)

4 Land Capability Assessment (if applicable – refer to Land Capability Assessment

section of this document)

5 Current copy of Title and Plan of Subdivision

6 A copy of your Planning Permit (if applicable)

7 Applicable fee (refer to application form for current fees)

*Applications cannot be assessed until all documentation is received.

Important reminder:

Any septic tank system must comply with the EPA Code of Practice and the Australian

Standard for onsite wastewater management

Any septic tank work must be carried out by a licenced plumber.

31/05/17 Page 5

Selecting your septic system

This is a vital decision to ensure the system you select for your property will be sustainable and

suitable for the conditions of the site.

Information on types of systems is available in community fact sheets on Council’s website, on the

Victorian Environment Protection Agency (EPA) website and through discussions with your plumber

and Council’s Environmental Health Unit. Types of systems available are listed on the Victorian EPA

website under ‘onsite wastewater’.

Types of septic systems

The two most common types of systems installed in Golden Plains Shire are:

1. Primary treatment 2. Secondary treatment

This is a conventional septic tank connected to

absorption trenches, usually a gravity based

system.

This is either a septic tank combined with a

sand filter; or a packaged treatment plant.

Both types are commonly connected to

subsurface irrigation lines.

Factors which may determine your decision about which system to use include:

Restrictive site conditions i.e. heavy clay based soils, proximity to water courses or other

surface water, lot size.

Cost of installation and ongoing maintenance costs

Potential to irrigate garden and garden beds with effluent

Recommendations in a Land Capability Assessment (if applicable)

Restrictions on your land title relating to onsite wastewater disposal.

Placement of septic systems

Discuss with your plumber the suitable placement of the septic tank system and note that

construction over any part of the system is prohibited.

Factors to consider when weighing up proposed location of the septic tank system include:

Restrictions on title or planning permits regarding placement of a wastewater system (if

applicable)

Recommendations from a Land Capability Assessment (if applicable)

Locations of future sheds, house extensions, swimming pools, tennis courts, dog yards,

clotheslines, garden paths and driveways

Required fall from the house to the septic tank system (discuss with your plumber)

Location of internal plumbing and main outlet from the dwelling

Setbacks to site boundaries, surface water, dams, drainage easements, storm water drains,

services, buildings (refer to setbacks / buffer distances of this document)

Future landscaping (some systems are able to reuse effluent to irrigate garden beds if

constructed early)

Septic tanks are installed at ground level so lids, vents, alarms are visible – consider whether

you want to see these components from your lounge room and/or decking area.

31/05/17 Page 6

Providing a site plan with your application

The Site Plan provided with your application must be legible and detailed.

Septic tank Site Plans are just as important as your Building Plans - rough sketches with no site

details will not be accepted.

Failure to provide a suitable plan with your application will result in a delay to the processing of your

permit as you will be asked to resubmit.

If your neighbour has a dam on their boundary, or you have a dam or waterway running through

your property, it must be shown on your plan. An appropriate site plan will ensure that everyone

understands the required works and your permit can be issued without delay.

The following details need to be included on your plan:

Locations and dimensions of all buildings

or proposed buildings

Locations and dimensions of all current

and proposed structures such as

swimming pools, tennis courts, dog yards,

garden paths, driveways, cubby houses,

etc

Water tanks, water pipes, storm water

drains

Driveways

Underground power, water and

telecommunications connections

Sites with hills, an indication of surface

runoff

Location of proposed system including

disposal field

The position and direction of North

The fall of the land

Distances from the closest part of the

septic system to site features including;

property boundaries, buildings, sheds,

other services, waterways, dams and

easements.

On the following page you will find examples of Site Plans:

i Note: your Site Plan is

important – a poor plan will

result in delays to the

processing of your permit as

you will be asked

to resubmit a suitable plan.

Plans don’t have to be

professionally drawn

but they do need to

be clear, legible and

detailed.

Your builder needs

detailed plans to build

your house and your

plumber needs

detailed plans to

install a septic tank.

Include as much detail

as possible on your

plan.

31/05/17 Page 7

Suitable site plan – example 1 – Septic tank and absorption trenches

31/05/17 Page 8

Suitable site plan – example 2 – AWTS and subsurface irrigation

31/05/17 Page 9

Land Capability Assessments

Do you need a Land Capability Assessment?

If your property/development meets any of the following criteria, a Land Capability Assessment

(LCA) will be required. Is your site:

smaller than 4000 m2 (1 Acre)

within the Moorabool (Sheoaks) Open Potable

Water Catchment Area

classified as high risk for groundwater –

groundwater is of high quality and within 5 metres

of the surface

of a slope of greater than 20%

covered by 50% or more FO (Flood Overlay)

smaller than 2 hectares and a primary treatment

system is proposed in an area where clay based

soils are evident

a non-residential development.

About Land Capability Assessments (LCA)

LCA’s are to be prepared in accordance with EPA publication 746.1 and the MAV – Victorian Land

Capability Assessment Framework and must be carried out by a suitably qualified consultant (soil

scientist or hydro-geologist).

A LCA will detail the groundwater depth, soil permeability, average rainfall, soil category rating; soil

classification and any other aspects of the site relevant to that particular property. The information

contained in a LCA report will determine a range of recommended irrigation and effluent disposal

designs that are dependent on soil classification.

If a LCA is required for your property, you need to engage an assessor and ask them to contact

Council to discuss the assessment with an Environmental Health Officer prior to commencement.

This will ensure that the assessment addresses any constraints specific to the site. Ensure you

provide the assessor with all the relevant information including future land use plans, such as plans

for house extensions or sheds.

Details of areas in Golden Plains Shire which are classified ‘high risk groundwater’ and

‘heavily sloped’ are detailed in Map 16 of Council’s Domestic Wastewater Management Plan

(available on the website)

If you are unsure if your application requires a LCA, please make sure you contact Council

and speak with an Environmental Health Officer prior to lodging an application.

i Note: in rare circumstances,

there may be an accumulation

of additional constraints that,

upon assessment of an

application by Council,

warrant a LCA.

31/05/17 Page 10

Conventional septic tanks

Septic tanks must comply with Australian Standard AS/NZS 1546.1.

Conventional septic tanks are a minimum of 3200 Litres. Wastewater is retained within the tank for

a minimum of 24 hours where solids settle to the bottom of the tank and anaerobic digestion of

organic solids occur. The liquid content is discharged to absorption trenches preferably by gravity, or

by a pump well where sufficient fall cannot be achieved.

Septic tanks are to be de-sludged every three years or as required upon assessment by a suitable

contractor. Septic tanks need to be installed in stable ground and all inspection openings must be at

ground level so that the tank can be located and maintained i.e. inspection openings, inlet of septic

tank and access lids.

31/05/17 Page 11

Absorption trenches

Absorption trenches must be constructed in accordance with Australian Standard AS/NZS 1547.

Absorption trenches are a traditional method of disposal of wastewater from primary treatment

septic tank systems. The trenches are constructed with a “slotted pipe” or “arch tunnel” to distribute

the effluent evenly along the trench.

The effluent is disposed of by:

a) absorption into the surrounding soils

b) transpiration into roots of grasses above the trench and

c) evaporation through the top-soil.

Absorption trenches are to be a maximum length of 30 metres, a minimum 2 metres apart, each

installed with a distribution box at the beginning of the trench with access at ground level. The top

of the trench is to be mounded to allow for natural settlement of soil and to stop surface water

entering the trench. Absorption trenches are not suitable in heavy clay based soils.

Construction of trenches are to be in accordance with the following schematic:

Aggregate is to be 20-40mm clean, hard quartz stone or other approved stone free of dust, dirt,

loam, soft particles, organic and other foreign matter.

Trenches are to be installed a maximum of 400mm deep. Deeper trenches will cause the system to

fail. Where sufficient fall cannot be achieved between the septic tank and absorption trenches to

maintain this depth, a pump well will need to be installed prior to the trenches.

31/05/17 Page 12

Sand filter systems

Sand filters are a secondary treatment system installed after a conventional septic tank prior to

the effluent disposal system.

Sand filters distribute effluent from a septic tank across a bed of sand. As the effluent passes

through the sand, aerobic oxidation occurs dissolving and suspending the organic matter. This

results in a higher level of treatment to the effluent.

When installing a sand filter system, the sand filter needs to be sized accordingly to the hydraulic

and organic load for the proposed system. The following table provides minimum sand filter sizes.

These have been calculated based on AS/NZS 1547 and the EPA Code of Practice. Without additional

evidence to support the reduction of the size of the sand filter, the size provided in the tables is the

minimum that will be approved within Golden Plains Shire.

Sand Filter Size

Number of

habitable rooms Sand filter size

1 6 m2

2 9 m2

3 12 m2

4 15 m2

5 18 m2

Sand filters are to be installed in accordance with EPA certificate of approval 1.3/03 and the

schematic on the following page.

i Note: a habitable room

includes any room that may

be closed off with a door,

such as a study, library or

sunroom that could be used

for the purposes of a

bedroom.

31/05/17 Page 13

Aggregate is to be clean, hard quartz stone or other approved stone free of dust, dirt, loam, soft

particles, organic and other foreign matter.

Small aggregate is to be 5-10mm in size.

Large aggregate is to be 20-25mm in size.

Sand layer is to be clean washed sand that:

o Contains less than 5% clay and fine silt content by volume

o Has an effective size between 0.25 and 0.6mm

o Has a uniformity coefficient less than 4

In addition to the above schematic, the following are requirements of installation of Sand Filter

Systems:

Distribution boxes are to be installed so that the access cover is at ground level

Base of the sand filter is to be lined

Distribution pipes are to be 90mm slotted pipe a maximum 1 metre spacing apart and a

minimum 500mm from the edge of the sand filter

The distribution and/or distribution pipes are to be vented

Pump wells are not to be installed inside the sand filter.

Aerated Wastewater Treatment Systems (AWTS)

AWTSs are a secondary treatment system installed prior to the effluent disposal system.

AWTSs aerate effluent from a septic tank (or primary chamber) using electrically powered blowers.

In addition to aeration, clarification and disinfection is often used to achieve a higher level of

treatment. AWTSs are required to be serviced by a qualified service agent once every quarter and

the report provided to Council. AWTSs are required to be installed in accordance with the relevant

EPA certificate of approval for the system. A list of approved AWTS can be found on the Victorian

EPA website under ‘onsite wastewater’.

31/05/17 Page 14

Sub-surface irrigation systems

Sub-surface irrigation disposes of effluent through a network of pressure-compensating pipes and

emitters in the sub-soil (100-150mm below ground level).

Irrigation systems are the preferred effluent disposal method for secondary treated effluent i.e.

effluent which has been treated through either an AWTS or a sand filter system. As there are

different types of pipe available, irrigation pipe is required to be approved for use with waste water.

Irrigation pipe must be purple or lilac in colour. Irrigation systems are to be fitted with a in-line mesh

filter, an air valve and a flush valve as per manufacturer’s specifications. Larger irrigation systems

(generally above 400 m2) should be zoned in accordance with pump capacity. Sub-surface irrigation

can be used in clay based soils in combination with gypsum application and can be used to irrigate

gardens and garden beds. Irrigation systems need to be flushed periodically and the filter cleaned

regularly (normally fortnightly to monthly).

Disposal field sizing

A LCA will determine the size of your disposal field (irrigation area required) in the report.

To assist property owners who are not required to obtain a LCA, the table included in the ‘Sizing of

Effluent Disposal Systems’ section outlines the minimum disposal area for onsite wastewater

disposal. These figures have been calculated based on AS/NZS 1547:2012 and the EPA Code of

Practice. They are based on a clay dominated (Category 6 – DIR/DLR 2 mm/day) soil type and

therefore provide a conservative approach.

The minimum disposal areas provided in the table are a

minimum that will be approved within Golden Plains

Shire Council, unless additional evidence (e.g. a LCA) is

provided to support the reduction of the recommended

area.

Final approval of your effluent disposal area will be

finalised after an assessment of the site and the

supporting documentation by Council’s Environmental

Health Officers. Please note that the installation of high

water volume features, such as spas, will require

additional disposal field area to be installed.

i Note: a habitable room

includes any room that may

be closed off with a door,

such as a study, library or

sunroom that could be used

for the purposes of a

bedroom.

31/05/17 Page 15

Sizing of effluent disposal systems

Due to an increased average rainfall in the northern part of the Shire, an additional 10%

recommended minimum disposal area is required to cope with the additional wet conditions.

Generally any property north of the townships of Rokewood and Maude are classified as medium

rainfall areas. Detailed mapping on this criteria is available in Map 12 of Council’s ‘Domestic

Wastewater Management Plan – Volume 2’, which is available on our website.

Other important considerations:

All disposal fields must be a permanent dedicated area within the property boundaries

It must be protected from vehicles and livestock

Do not place your disposal field in a paddock that will be planted and harvested

For construction of new dwellings it is important to think about your landscaping plans at

septic tank application stage, as irrigation can also be used in garden beds.

Absorption/transpiration trenches (with PVC pipe/reln or arch drain)

Number of habitable

rooms

Minimum disposal area

required (Low rainfall) Minimum disposal area (Medium rainfall)

1 60 m2 66 m2

2 90 m2 99 m2

3 120 m2 132 m2

4 150 m2 165 m2

5 180 m2 198 m2

Subsurface irrigation (secondary treated effluent only)

Number of habitable

rooms

Minimum disposal area

required (Low rainfall) Minimum disposal area (Medium rainfall)

1 150 m2 165 m2

2 225 m2 248 m2

3 300 m2 330 m2

4 375 m2 413 m2

5 450 m2 495 m2

31/05/17 Page 16

Setbacks/buffer distances

Setbacks are predetermined distances that must be maintained between site features and any

part of the treatment system and disposal field.

These distances have been determined by the Environment Protection Authority and must be

adhered to at all times. The following setback distances are required for all septic tank system

disposal fields.

Don’t forget that setback distances also apply to features on neighbouring properties.

Landscape feature or structure

Setback distances (m)

Primary

treated

effluent

Secondary

sewage and

greywater

effluent

Building

Wastewater field up-slope of building 6 3

Wastewater field down-slope of building 3 1.5

Wastewater up-slope of cutting/escarpment 15 15

Allotment boundary

Wastewater field up-slope of adjacent lot 6 3

Wastewater field down-slope of adjacent lot 3 1.5

Surface waters (up-slope of)

Dam, lake or reservoir (potable water supply, includes water

for food production) 300 300

Waterways (potable water supply) 100 100

Waterways, wetlands (continuous or ephemeral, non-

potable); estuaries, ocean beach at high-tide mark; dams,

lakes or reservoirs (stock and domestic, non-potable)

60 30

Groundwater bores

Potable or non-potable 20 20

Services

Water Supply pipe 3 1.5

Wastewater up slope of potable supply channel 300 150

Wastewater field down-slope of potable supply channel 20 10

Gas supply pipe 3 1.5

In-ground water tank 15 7.5

Stormwater drain 6 3

Recreational areas

Children’s grassed playground (school, council, community or

other children’s playground) 6 3

In-ground swimming pool 6 3

31/05/17 Page 17

Permit to Install

Council will issue a Permit to Install if the proposed system is suitable for the development, the

application is filled in correctly (including a detailed plan on the page provided) and copies of any

other information required are provided.

If a permit has been issued and the applicant changes details of the system and/or the registered

plumber, then an application to amend a permit must be completed. A fee will apply for this

application. This form can be found on our website.

The Permit to Install is valid for two (2) years from the date

of issue. Should the works take longer than the two (2)

years, the applicant must complete an Application for a

Permit Extension prior to the expiry date. A fee will apply for

this application. This form can be found on our website.

NO work can commence on the installation of your system

until you have received your septic tank permit. Please note:

All permits are issued with conditions. Compliance with the

permit conditions is required.

Inspections of your system

All septic systems require mandatory inspections which must be conducted by Council’s

Environmental Health Department.

Inspection are carried out a) prior to issuing a Permit to

Install, b) when the system is being installed and c) a final

inspection when the system has been completed.

You or your installer must contact Council’s Environmental

Health Officer two (2) working days prior to installation to

arrange a suitable time for the installation inspection.

Allow ten (10) working days after final documentation is

received (refer to the next page) for a final inspection to be

carried out and a Certificate to Use being issued.

To arrange your inspection please contact Council’s

Environmental Health Department on

03) 5220 7111.

i Note: please allow up to

four weeks for the

processing of your Septic

Tank Application.

i Note: all inspections are

mandatory and will

determine whether Council

will issue a

Certificate to Use. Failure to

book in an installation

inspection may result in

your Certificate to Use not

being issued.

31/05/17 Page 18

Certificate to Use

The following additional information is required prior to a final

inspection and a Certificate to Use being issued:

A copy of the Plumbing Industry Certificate

If a package treatment plant is installed, a

commissioning certificate

If a pump well is installed, an electrical certificate, and

An ‘as installed’ plan.

Maintenance

Owners of a septic tank system must comply with the Certificate to Use and relevant EPA

certificate of approval and maintain their system in good working order.

i Note: the issuing of a

Certificate to Use is a legal

requirement. Your system

should not be used until

approval has been

granted. Fines apply when

a system is used without

approval.