las vegas water reuse 2

7/28/2019 Las Vegas Water Reuse 2

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Water Recycling Study

Southern Nevada Regional


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Dear Valued Stakeholder:

While most people in Southern Nevada recognize the importance o maximizing our Colorado River and

local groundwater supplies, ar ewer appreciate the critical role that water recycling plays in extending

our communitys water supply. I not or the ability to recycle water, Southern Nevada would have

exhausted its available water resources many years ago.

Our community recycles water in two ways: direct and indirect. Direct reuse is a process by which

wastewater ows are treated to stringent quality standards, then used or non-potable purposes such as

irrigation. Indirect reuse, which currently represents the majority o the Las Vegas Valleys water recycling

eorts, is achieved by treating wastewater to very high levels, then returning that water to Lake Mead. For

each gallon o water returned, a credit o one gallon is created. Through this mechanism, we are able to

stretch our water resources by billions o gallons each year.

While indirect recycling is eective, additional direct reuse oers several potential benets, including

reduced energy use or water treatment and delivery. In this report, we identiy options that will allow us

to expand upon our already successul water recycling program and make optimal use o our communitys

water resources.

The Southern Nevada Regional Water Recycling Studywas developed with involvement and input rom a

diverse group o stakeholders, all o whom have a strong interest in current and uture water recycling

eorts. The report includes specic public policy recommendations with respect to water reuse.

The authors o this report believe that adoption o the principles and recommendations contained herein

will promote the optimal use o our regions scarce water supplies. Please take the opportunity to review

this document and reect upon the recommendations. I you have any questions, please do not hesitate

to contact either o us. With your guidance and support, we can protect and extend our communitys most

valuable resource and serve as a model or communities around the world.

Patricia Mulroy

General Manager

Southern Nevada Water Authority

Chip Maxeld, PE

General Manager

Clean Water Coalition

March 2009


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Purpose ofStudy

Recycled water accounts or roughly 40 percent o the

water used in Southern Nevada, making it our second

largest water resource and a critical piece o our waterresource portolio. In this study, we take a specic look at

water recycling and seek to identiy new ways to extend

our already successul water recycling programs while also

seeking new opportunities to recycle and make better use o

the water we have.

This study provides recommendations or regional policies

and goals or water recycling that both complement our water

conservation program and help provide water resources or

continued growth in a sustainable manner.

Table o Contents

Purpose o Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Water Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

All Water is Recycled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Sustainability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Setting Recycling Goals or the Future . . . . . . . . . . . . 7

Current Water Resources and Use . . . . . . . . . . . . . . . . . 8

Water Recycling Today . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Las Vegas Valley Treatment Plantsand Recycling Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

How is Recycled Water Used Elsewhere?. . . . . . . . . . 1 2

Recycling Practices Vary by Community . . . . . . . . . . 1 4

What About Graywater?. . . . . . . . . . . . . . . . . . . . . . . . .15

Stakeholder Research. . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Guiding Principles or Water Recycling . . . . . . . . . . . 1 8

Choices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

Weve been recycling water in Southern Nevada

or over 50 years, and oppor tunities exist

to recycle even more.

Southern Nevada Regional Water Recycling Study

www.snwa.com

www.cleanwatercoalition.com


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Southern Nevada Water Authority Clean Water Coalition Black & Veatch2

Aquier: A geologic ormation under the ground that is

saturated with groundwater and sufciently permeable to

allow movement o quantities o water to wells and springs.

Aquier Storage and Recovery: A management strategy

in which water is treated and articially recharged to an

aquier system or later withdrawal.

Direct Potable Reuse:The introduction o reclaimed

water directly into a drinking water distribution system

(pipe to pipe).

Direct Reuse:The use o reclaimed water or nonpotable

purposes without rst discharging to a water supply source.

Graywater: Untreated used water rom bathtubs, showers,

bathroom sinks and clothes washers. Does not include water

rom toilets, kitchen sinks or dishwashers.

Indirect Reuse:The use o reclaimed water or nonpotable

or potable purposes by discharging to a water supply source,

such as resh surace water or groundwater, where it mixes,

dilutes, and may be transormed beore being removed or

reuse.

Indirect Potable Reuse:Augmenting a communitys

raw water supply with reclaimed water ollowed by an

environmental buer. The mixed reclaimed and raw water

receives additional treatment beore entering the potable

water distribution system.

Potable Water:Water that meets all applicable ederal,

state and local requirements concerning saety or

drinking water.

Reclaimed Water:See Recycled Water

Recycled Water:Wastewater that has been treated, then

used or a benecial purpose. Also called Reclaimed Water

or Reuse Water.

Water Treatment: The act o removing contaminants

rom source water by biological processes, chemical addition,

ltration and disinection to puriy the water or it next use.

To urther the discussion about water recycling, it is

important to have an understanding o the terms and

phrases that are commonly used.

For the purposes o this study, a collection o these

terms and phrases and their associated denitions is

provided below:

Water Terminology


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Water recycling is simple its nothing more than taking

water weve already used and using it again. In act, all

water is recycled, and always has been.

Through the process o evaporation, water makes its way to

mountains and rivers in the orm o precipitation (rain, snow),

runs over (or under) the earths surace and back to the ocean,

where it begins the process over again. Along

that journey, some o this water is used by plants,

animals and people, but the water is always

returned to the system. I we think about the

earths water cycle as a circular process, it would

represent a very large circle.

In Southern Nevada, we recycle water at a local

level similar to the earths water cycle, only

smaller. Water recycling means collecting the

water weve already used, treating it and using it

again here in our community.

In act, we already recycle about 40 percent o our water

here in Southern Nevada with the aid o something called a

Return Flow Credit. Return ow in Southern Nevada relies

on the concept that or every gallon o treated Colorado

River water returned to the Colorado River, we can

withdraw and use an additional gallon beyond Nevadas

base allocation. Southern Nevada is unique among major

cities that rely upon the Colorado River because our

All WaterisRecycled - Its Just a Matter of How Fast

Water Cycle

The Earths water

is constantly being

recycled.

Water recycling

means collecting

the water weve

already used,

treating it and

using it again

here in our

community.

proximity to the river allows us to very efciently recycle

water through this withdrawal and return mechanism.

Las Vegas Wetlands Park


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Southern Nevada Water Authority Clean Water Coalition Black & Veatch

The Right Quality or the Right Use

What is water quality and how does

it afect how we meet our needs?

Water quality is a term used to describe

the characteristics o water in relation to

its intended use. Even though the water

part rom every source is the same,

water quality varies depending upon the unique biological

and chemical characteristics contained in each dierent water

source. The quality o water varies depending on what that

source contains besides just water. Regardless o the source, the

water we use is treated to ensure that it meets specic ederaland state water quality requirements .

For instance, our drinking water is treated by processes

specically designed or the water quality o our local source

waters to ensure that it meets or exceed

all ederal and state requirements ordrinking water.

Similarly, our wastewater is treated in multiple

steps beore it is returned to the environment.

In Southern Nevada, the wastewater treatment

plants are among the best in the country, combining

biological treatment, nutrient removal, chemical treatment,

ltration, disinection and neutralization o any added

chemicals. This recycled water consistently satises all

ederal and state water quality requirements or its next use.Sometimes this next use is the irrigation o parks, gol courses

or industrial uses. Recycled water not used or these needs is

returned to the Colorado River system where it is available or

our use and by others in Arizona, Caliornia and Mexico.

4

Our Level o Wastewater Treatment

Treatment plants receivewater and treat it to a

level that is appropriate

or its next use.

Water Quality

Better Treatment

Cities

Miami, FL

San Francisco, CA

Philadelphia, PA

Portland, OR

Cities

Denver, CO

New York City, NY

Houston, TX

Chicago, IL

Cities

Los Angeles, CA

Phoenix, AZ

Atlanta, GA

Dallas, TX

Cities

Las Vegas, NV

Scottsdale, AZ

Placerville, CA

El Paso, TX


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Water Quality Monitoring and TestingEnsures Public Saety

Between the various agencies responsible or managing

our water quality, hundreds o thousands o tests* are

run on our water each year in its various stages o use,

treatment and reuse. This continuous monitoring and

testing helps protect our water quality and the publics health

and saety.

Recycled water that is directly reused or returned to the

Colorado River is tested by Nevada Division o Environmental

Projection (NDEP) certied testing laboratories to ensure

that it meets requirements set orth or benecial uses.

Benecial uses include such things as recreation, aquatic

lie, sheries, irrigation, and source water or drinking water

supply. The Environmental Protection Agency and the NDEP

monitor the results o the tests.

Similarly, water drawn

rom the Colorado

River is tested beore

and ater treatment,

as well as at multiple

points within the

potable water

distribution system.

This ensures that it

meets or exceeds

the standards o the

Federal Sae Drinking

Water Act.

And at every point in

the cycle, the people

who are responsible or treating the water, testing its quality

and overseeing the process are certied operators and lab

analysts, licensed proessional engineers, or other similarly

qualied proessionals whose primary responsibility is the

saety o our water and the protection o the environment.


Continuous monitoring and testing helps

protect our water quality and the publics

health and saety.

Water drawn rom the Colorado River

is tested beore and ater treatment.

*The water supply is analyzed or metals and inorganic compounds, radiological constituents, bacteria, viruses, protozoans (such

as Cryptosporidium and Giardia) and organic compounds.

Recycled water on its way to the Colorado River is sampled

and tested to protect water quality in the river.

Water Quality


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With todays increased environmental awareness and

a strong shit in values toward more sustainable living

practices, communities everywhere are reevaluating

how they use their resources.

In Southern Nevada, we also recognize that as we satisy

our present needs, we must do so in a way that does not

compromise the uture o our community.

What does it mean to be sustainable?Most people

associate it with protecting the environment. And while

it does ocus on environmental protection, sustainability

also takes in economic and social/cultural considerations.

A sustainable solution is one that represents a goodbalance between these three concerns. In the context

o water recycling, sustainable applications or its use

are evaluated in this same way. Water managers look or

opportunities to use recycled water cost eectively and in

ways where our treatment processes can eectively achieve

a high quality o water. When used in the right applications,recycled water can save energy, reduce the need or new

inrastructure, and in some instances result in an increase in

the water supply available to a community.

Sustainability

6

While it does ocus on environmental

protection, sustainability also

takes in economic and social/cultural

considerations.

Economic

Social/Cultural

Environment

Sustainability

Sustainability

Sustainable solutions

balance competing interests

EconomicGrowth and Developmen

Job Creation

Social/CulturalQuality o Lie

Community Perception

Social Values/Priorities

Environment

Pollution Prevention

Habitat Conservation

Resource Protection


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Our water resource picture is changing. The efects o

prolonged drought within the Colorado River basin

are causing stress on water resources throughout

the entire region. And the difculties caused by this

water scarcity are unlikely to go away anytime soon.

Most experts believe that the earths climate is changing,

and that one o the eects o this climate change is the

reduction in precipitation making its way into the lakes

and rivers o the Colorado River basin.

While no one knows or certain what the uture holds,

we must nd ways to make all o our water resources go

urther. Now is the time to look at how we collectively use

our shared resources and use the opportunity to set new

goals or using recycled water.


The Big Picture

Setting Recycling Goals for the Future

The Study Process

In order to provide the background needed or an inormed discussion about how we use

water and how recycled water should t into our uture, this study utilized a multi-step

process.

Recommendprinciplesandgoals.

What are ourwater needs,and how dowe use ourvarious waterresources tomeet them?

How do wecurrently userecycledwater?

How isrecycled waterused in otherparts o thecountry andthe world?

How do wecompare toother places,and whatmakes senseor ourcommunity?

The eects

o prolonged

drought within

the Colorado

River basin

are causing

stress on water

resources

throughout the

entire region.


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Where Our Water Comes From and HowWe Use It

In order to make good decisions and set goals or using

recycled water, we need to know something about how

our water ullls our

needs. So where does our

water come rom, and

how do we use it?

Almost all o the water we

use in Southern Nevada

(nearly 90 percent)

comes rom the Colorado River, with the rest coming rom

groundwater wells. When we actor in the amount o

recycled water we use in Southern Nevada, we see that it

makes up nearly 40 percent o our total water resources.

How do we use the water we have?

Most o the water used in Southern Nevada is used at

our homes and most o that is used outdoors. I we look

beyond the water used at our homes, the remaining water

is used by companies and or services that support our

local economy and quality o lie.

How do the various uses we have or water help us

shape our water recycling goals?

The answer lies in our ability to collect water rom these

dierent uses so it can be treated and used again. I we

use the water in ways that allow us to capture it ater use

(indoor uses that send water down the drain) then we

can recycle it. But if the water cant be captured after weve

used it the rst time (such as outdoor irrigation) then we

cant recycle it.

Current Water Resources and Use

8

2008 Water Supply40%

60%

Surface and Groundwater

Recycled Water

Water Resources

Water Use

44%

15%13%

7%

5%

7%

5%4%

Residential (Single Family)

Residential (Multi-Family)

Commercial / Industrial

Resorts

Golf Courses

Schools / Government / Parks

Common Areas

Other

Recycled water

provides nearly

40 percent o

our total water

resources.


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In the end, how we satisy each need or water is not

a one-size ts all process, but rather a decision that

balances cost, resource availability, water quality and

other actors to come up with the best answer or that

water need in that community. How do we strike this

balance?Thats where setting goals comes in, and well

get to that later in this report.

Approximate Annual

Volume o Indirect

Water Recycling 186,000 acre-eet

Approximate Annual

Volume o Direct

Water Recycling

27,000 acre-eet

Gol Courses Irrigated

with Recycled Water 30

Power Plants Using

Recycled Water or

Cooling 2


Our Current Water Recycling Practices

Did you know that we have been recycling water in

Southern Nevada or over hal a century and or over

20 years it has been a part o our strategic water

resource plan?

Most o the water that goes down our drains (sinks, showers,

toilets) is ultimately returned to the Colorado River, but not

until it has been treated and tested to make sure that it is

clean enough to be returned to the water cycle (reer to the

water cycle on page 3). But some of the water that has been

treated comes back to our community (without going to the

river) or benecial use. While we dont use this recycled water

or drinking, we are able to use it to meet many o our other

water needs.

Recycled water is currently used or gol course, green belt and

median irrigation, cooling water or power plants, water or

dust control, and other minor uses. And it is important to note

that while many o our gol courses use recycled water, not all

do. The same is true or the other applications in which we use

recycled water a combination o recycled water and potable

waters are used to meet their overall needs. Some water needs

are minimized through conservation as well.

Water RecyclingToday

Return Flow Credit


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5

6

7

4

9 8

12

3

NorthLas Vegas

Las Vegas

Clark County WaterReclamation District

Henderson

SunriseStation

Power Plant

Las Vegas Wash

Clark StationPower Plant

Silver BowlSoccer Field

Complex

MedianLandscaping

AlongBoulder Hwy

McCarran IntlAirport

Return Flow toLake Mead

PalmMortuaryCemetery

(Irrigated withRecycled

Water)

159

215

15

15

159

93

215 93

95

160

160

215

515

515

0 1 2 3 40 5

miles

Treatment Plants

Power Plants

Wetlands Park

Golf Courses that currently use

reclaimed water (30)

Legend

City of Henderson

City of North Las Vegas

City of Las Vegas

Clark County Water Reclamation

District Service Area


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In Some Places, Water Recycling MayNot Be the Best Answer

Water recycling is oten more expensive than treating

and discharging wastewater and relying on

non-recycled sources to meet water needs.

Communities that have an abundance o

water resources that exceed their needs

oten dont recycle, primarily because the

cost o building and operating the treatment

and distribution systems required to supply

recycled water just isnt justied.

Many Communities UseRecycled Water or Irrigation

The single most common use or recycled

water is or outdoor irrigation. The typical

water customer who buys recycled water

or irrigation uses it to water gol courses, public median

landscapes, and certain types o agriculture. While

the recycled water treated or irrigation is not suitable

or drinking, the water needs o many plants can be

satised by recycled water as long as careully managedwatering practices are in place.

School and Parks

Using recycled water or irrigating landscaping at schools,

ball elds and parks is given careul consideration becauseo the increased potential or human

contact with the recycled water.

However, extensive study and many

years o use at schools and parks in

other communities show that this is

a responsible use o recycled water.

Because recycled water for irrigation

is not treated to a potable standard,

signage and specially colored piping and

sprinkler heads identiy it as recycled and

instruct people not to drink it.

Recycled Water Can Be Usedto Supplement Groundwater

In some communities, the groundwater aquier is their main

water resource. They draw the groundwater rom wells

and use it to meet the community water needs. But where

groundwater supplies are limited, and when the need or

groundwater exceeds what can be replenished naturally,recycled water can be used to replenish the groundwater

supply and help these communities maximize their

groundwater resources.

2

The typical water customer who buys recycled

water or irrigation uses it to water gol courses,

public median landscapes, and certain types o

agriculture.

Silver Bowl Park

How is Recycled Water Used Elsewhere?

Aquier Storage and Recovery


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Prevention o Seawater Intrusion IntoPotable Aquiers

For coastal communities that rely heavily on groundwater,

pumping groundwater rom aquiers near the ocean can

result in a lowering o the water table and an inux o

seawater into the same aquiers they rely on or drinking

water. In these communities recycled water injected into

the ground can help increase groundwater pressure and

prevent the migration o seawater into the potable aquier.

Industrial Uses

Many businesses use water or manuacturing and

industrial processes, and or some o these uses, recycled

water is a viable option to meet their needs. Common

industrial uses or recycled water

include evaporative cooling

towers, washing o aggregates or

concrete, soil compaction and dust

control, commercial laundries and

car washes. For industrial uses, the

specic water quality requirements

or each use are evaluated, and

requirements or supplemental

treatment (i needed) are identied.

Indirect Potable Reuse

Southern Nevada is one o many communities that indirectly

augment drinking water supplies with recycled water. Whileour current eorts augment

our surace water supply

(the Colorado River), some

communities use recycled

water to stretch surace

and/or groundwater

supplies. Other examples

include Orange County,

Caliornia, the greater Denver metropolitan area that includes

Aurora, Colorado, and Atlanta, Georgia. Indirect Potable Reuse

is practiced internationally as well.Singapores national water

agency currently ullls 15 percent o total water demands

with recycled water, with a small proportion o this percentage

contributing to indirect potable reuse.

Direct Potable Reuse

At the most aggressive end o the water recycling spectrum is

the concept o taking recycled water, treating it to the same

potable standards that would apply to any other source water,and then placing it directly into a potable water distribution

system without the benet o buering or dilution rom

another body of water. Because of the increased public health

risk and public perception difculties associated with such an

approach, direct potable reuse

applications are extraordinarily

rare, and are not permitted by

state or ederal regulations in

the United States. In act, only

one documented instance o a

municipal water system utilizing

this approach could be identied

Windhoek, Namibia.


Recycled Water can be used to satisy industrial

cooling water needs.

Recycled water is used

in Southern Nevada

to supplement surace

water supplies as

Indirect Potable Reuse.

How is Recycled Water Used Elsewhere?

Seawater Intrusion Barrier


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Diferent Places, Diferent Practices

I you look at the range o

water recycling practices usedelsewhere, and then compare

them with the water recycling

practices we currently use in

Southern Nevada, youll notice

some diferences.

Why do recycled water use

practices dier rom place

to place?Simple the water

recycling practices each areauses are balanced responses

to the water needs, available supplies, water rights/

regulatory ramework and the costs associated with

meeting the water needs o these individual communities.

Because the constraints and challenges of supplying water

to these various communities are dierent, the waterrecycling practices adopted may dier as well.

Even within Southern Nevada, recycling practices vary or

the individual communities in the region. For instance,

most o our communities are located such that they can

recycle water indirectly via return ow to the Colorado

River. But for those communities where return ow to the

Colorado River is impractical, a dierent set o recycled

water priorities may be in order. The inability to return

recycled water to the Colorado in these communitiesplaces a greater value on direct uses o recycled water such

as irrigation and industrial uses, and oers the opportunity

to engage in other orms o indirect recycling such as

Aquier Storage and Recovery.

4

Recycling Practices Vary by Community

Southern Nevadas Constraints and Challenges Vary with the Region

Community can

Return Water toColorado River

Recycling EortsEmphasizeIndirect Recycling

Community cantReturn Water toColorado River

Recycling Eorts

Emphasize DirectRecycling

Colo

rado

Riv

er

Supply

Retu

rnFlow

Gro

undwater

Gro

undwater


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Both graywater and recycled water have a common ideabehind them, which is to use water more than once. But if

you look back to the denitions rom page 2, youll see there is

a critical dierence. Recycled water has been treated to a high

standard to make it sae or many uses, whereas graywater

receives no treatment at all.

A recent publication rom the World Health Organization

noted the potential implications o graywater on public health.

Because graywater has the potential to transmit disease,

graywater systems are typically required to be designed to

avoid human contact through the use o subsurace irrigation

systems. This potential risk o disease is accepted in some

communities as the trade-o or the reduced demand on

their water supply. In Southern Nevada, however, graywater

use would not reduce demand on our water supplies since

our current practice o recycling it returns the water to our

supply source. In either case, graywater users dont use

less water than non-graywater users. Since the graywater

used would have otherwise been sent to a wastewater

treatment acility and recycled, no water is saved. In act,

a recent analysis o water use data or graywater users

in Western Australia yielded data that indicates just the

opposite. Data showed that homeowners who installed a

graywater reuse system and subsurace irrigation system

actually increased domestic water consumption. More

investigation is planned by Australian water managers

to understand the reasons underlying this surprising

result, but they currently suspect that homeowners

are rationalizing that they can use more potable water

because they are making irrigation water.

Our current potable and recycled water practices yield

the same or better use o the water while avoiding

the potential human health risks associated with

graywater.


As graywater is contaminated with

ecal coliorms [an indicator o ecal

contamination] and some chemical pollutants

rom bathing and laundry, microbial and

chemical contamination o graywater poses

a potential risk to human health, and so it is

important to recognize that graywater does

have the potential to transmit disease.

Overview o Graywater ManagementHealth Considerations, World Health

Organization, 2006.

What About Graywater?

Graywater and Recycled Water Are Notthe Same

The rebates or alternative water sources...

appear to be very eective. The exception

appears to be graywater reuse

systems that are associated

with an increase in

consumption o scheme water.

Waterwise Rebate Scheme

Review 2007, Data Analysis

Australia Pty Ltd, April 2008.

Recycled water has been treated to a

high standard to make it sae or many

uses, whereas graywater receives no

treatment at all.


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Community Leaders Weigh In

To understand the values, priorities and concerns o

Southern Nevadans about how we use water and howrecycled water ts into the picture, ace-to-ace interviews

with 49 community leaders were conducted.The community

leaders interviewed included representatives rom

government, development, business, green industry

and others. As a part o the interviews, a short overview

o water resource issues relevant to Southern Nevada was

provided, which was then ollowed by a 19-question, open-

ended survey to gauge views on various water issues in our

community. This survey and its results can be ound on both

the SNWA and CWC websites.

While an in-depth analysis o the interview results and

surveys would be too lengthy to include in this study, several

strong themes were evident in the discussions.

Saety o Recycled Water

Saety was one o the most prevalent themes

ound across the various opinions o thecommunity leaders. Because recycled water is

made by treating wastewater, multiple measures

are in place to protect public health. Nevada

has strict regulatory controls that govern the

production and use o recycled water. Local

agencies are responsible to see that the public

health and saety is protected

through adherence to these

regulations. There have beenno documented cases o

human illness in Southern

Nevada caused by contact with

recycled water.

Cost/Benet oRecycled Water

When asked various questions

related to the expansion o recycling practices to meet

certain water needs in Southern Nevada, one o the prevalent

themes voiced by most participants was the cost o the

recycled water in comparison to the benets it oers. Most

participants elt that i recycled water was a cost-eective

means to meet certain water needs when compared to

other water sources, then its use could be expanded and still

represent a net benet to the community.

Health and Saety o Graywater

Ninety percent o the people interviewed elt that our

current systems o potable and recycled water were more

benecial than graywater systems. Because graywater is

untreated, it contains pathogens and contaminants that pose

a public health risk, and this potential risk to public health

and saety was central to the discussions and concerns on

graywater. Recent developments among

builders who specialize in sustainable

building practices have led to proposals to

incorporate graywater systems in homesand major commercial developments, but

graywater systems are currently not permitted

by Southern Nevada building codes. Seventy-

nine percent o those interviewed thought

health and saety would be one o the greates

challenges in utilizing graywater systems.

6

Stakeholder Research

Seventy-nine

percent o those

interviewed thoughthealth and saety

would be one o the

greatest challenges

in utilizing

graywater systems.


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Goals Need a Sustainable Framework

Since one o the key objectives o this study is the

establishment o goals or uture water recycling practicesin Southern Nevada, we need to dene the guiding

principles that any such goals would ollow. With the insight

provided through interaction with community leaders, we

have the ability to establish principles that can be adopted

by the entities who manage our water resources.

8

Taken together, these principles provide a ramework

rooted in sustainability or establishment o water recyclinggoals. And because these principles speak to the values o

the community, they are robust enough to help us make

good decisions about recycled water in the uture when

our circumstances (how we use water, how much water we

have, etc.) may be dierent than they are today.

Sae

Treated to provide a high

degree o assurance that

public health and saety

is saeguarded.

Efective

Shown to be an eective

means o maximizing the

water resources available

to Southern Nevada.

Sustainable

Demonstrated to represent

the best balance o the

environmental, economic,

and social/cultural benets.

Efec

tiveS

afe

Sustainable

Guiding Principles:

Recycled Water resources should be developed and used in applications that are:

Guiding Principles for Water Recycling


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With a set o principles in place that will result in balanced choices or our communities, we developed a menu o recycled

water options that make sense or Southern Nevada. They include:


IndirectReuseasReturn

Flow

Useofrecycledwaterviadisc

hargetotheColoradoRivera

ndsubsequent

reuseinSouthernNevadahas

beeninpracticefornearly40

years,and

remainsoneofthemosteffec

tivetypesofrecycledwateru

seavailableto

ourcommunity.

Public/CommercialLandscapeIrrigation

Thiswouldincludeirrigation

ofpublicmedians,landscapingaroundpublic

orcommercialbuildings.Some

publicandcommerciallandsca

pesand

mediansinSouthernNevada

alreadyuserecycledwater.

GolfCourseIrrigation

Representingthemajorityof

directlyrecycledwaterusein

Southern

Nevada,golfcourseuseisap

roven,successfulpractice.

SchoolYardIrrigation

Whilerecycledwaterisnotc

urrentlyusedforirrigationat

schoolsin

SouthernNevada,u

secouldbeexpandedtoschoo

lsifsupportedbylocal

communities.

ParkIrrigation

Useofrecycledwateratpubli

cparksinSouthernNevadais

limited,and

usecouldbeexpandedtomor

eparksifsupportedbylocalc

ommunities.

IndustrialUses

Useofrecycledwaterforpow

erplantcooling,dustcontrol

and

constructionwaterisalready

practicedinSouthernNevada

.Additional

potentialindustrialusesforre

cycledwatermaybeviablein

Southern

Nevada.

AquiferStorageandRecovery

Useofrecycledwatertosupp

lementexistinggroundwatersupplieshas

recentlybeenprovidedforby

changestoNevadaregulation

s.Useof

recycledwaterforthispurpo

secouldbedevelopedifsuppo

rtedbylocal

communities.

Choices

RecycledWaterMenu


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Southern Nevada Water Authority Clean Water Coalition Black & Veatch0

Expand return fow to the Colorado River to increase Nevadas credit or subsequentwithdrawal.

We already recycle roughly 40 percent o the all the water we use in Southern Nevada by returning it to the Colorado River

or use again. Continuing eorts to reduce irrigation uses (which cannot be captured or recycled) mean that an increasing

proportion o our water is available or indoor uses that can be captured and recycled. This practice is sae, has been

practiced in Southern Nevada or over hal a century, maximizes our water resources, and makes good use o existing

inrastructure. By taking measures to expand this practice, we can gain urther benet rom a limited resource while

saeguarding the environment.

Expand the use o Recycled Water in the Las Vegas Valley where large tur andindustrial demands exist.

The use o recycled water to ulll the needs o large tur irrigation and industrial applications are the most common direct

water recycling applications in practice today. The technologies and practices to use recycled water or these needs are

proven and more than adequate to protect public health and saety. Though the use o recycled water or these needs

does not lessen the demand on Southern Nevadas water resources overall, sustainable uses o this type or recycled

water can still oer a net benet to the public. Such benets may include energy savings, decreased demand or new

inrastructure, and reductions in the nutrients being added to the Colorado River.

Maximize the use o Recycled Water in areas o Southern Nevada where return fow

to the Colorado River system is not practical, including the testing o aquier storage

and recovery.

The geography o Southern Nevada is such that not all o our communities are able to return recycled water to the

Colorado River. In communities where indirect recycling is impractical, direct water recycling becomes even more valuable

since it has the eect o increasing the water supply. And in order to make water recycling more efcient and cost eective

in these same communities, testing o an indirect method such as aquier storage and recovery is recommended.

Develop a Salt Management Strategy to address the accumulation o salts that are

detrimental in Recycled Water.

One o the side eects o the use o recycled water is the accumulation o salts in the ground. Because our recycled water

has a concentration o total dissolved solids (TDS a means o measuring salt concentration) that is roughly twice that o

Colorado River water, using recycled water or irrigation (our most common use) can be detrimental to the very plants we

are trying to support. Further, the very successul conservation programs used in Southern Nevada have reduced indoor

water use which also contributes to higher TDS. The development and adoption o a regional Salt Management Strategy

could eliminate barriers to urther use o recycled water.

Applying the guiding principles and considering the many uses or recycled water,seven recommendations are oered:

Recommendations

1

2

4

3


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Continue to advance the research o the health and saety implications o

Recycled Water.

The saety o public water systems is understandably one o oten voiced concerns when discussing the use o recycled

water. And because recycled water has been a resource drawn on by communities across the globe or many years,

a signicant body o research has lead to well-tested regulations and best practices or recycled water use. But as

the science o water quality continues to improve, opportunities to advance the research on the health and saety

implications o recycled water continue to be identied.

Prohibit the use o treated or untreated Graywater in the Las Vegas Valley, and

prohibit its use outside o the valley where there is reasonable potential or return

fow to the Colorado River system or other Water Recycling programs.

As it stands today, graywater systems are not permitted in Clark County. Unlike recycled water, which is highly treated

and regulated, graywater receives no treatment, which introduces the potential to transmit disease. Further, because

Southern Nevada has the ability to recycle water both directly and indirectly, the use o graywater would not result in

water savings. Southern Nevada water managers will continue to promote and regulate water quality and efciency

measures in homes and businesses.

Educate the public about our local water cycle and the benets o Recycled Water.

An inormed public is better able to participate in public policy discussions and decision making processes, but

much o the discussion about water resources in Southern Nevada requires knowledge that our residents may not

have. Community leaders interviewed as a part o this study share our desire to educate the community about

recycled water. A public outreach eort to provide the residents o Southern Nevada with the inormation needed to

understand our local water cycle and how reclaimed water is a part o that cycle would be a benet to the community.


Recommendations

5

7

6

Conclusion: The recommendations ofered in this study support Southern Nevadasexisting recycled water programs and ofer opportunities to expand them

as well as to promote new recycled water uses. These recommendations

and the guiding principles that support them are complementary to

the regions conservation eforts and provide sustainable solutions to

make the best use o Southern Nevadas water resources. Through these

practices, and through continued eforts to involve Southern Nevadans in

the discussion o our water resources and how best to use them, we can

maintain the reliable water supply that has helped make our community

a great place to live.


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This Study was commissioned by the Southern Nevada Water Authority and the Clean Water Coalition. It was conducted

by Black & Veatch, a global water resources and engineering frm, and supported by a group o subconsultants and subject

matter experts. The study began in late 2007 and was completed in early 2009.

For more inormation please contact,

Want More Inormation?

www.snwa.comwww.cleanwatercoalition.com

las vegas water reuse 2

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