&EPA WATER AVAILABILITY AND VARIABILITY STRATEGIES
United States
Environmental Protection
FOR PUBLIC WATER SYSTEMS
This document covers water availability and variability issues faced by public water systems, the potential
consequences of climate change on water availability and variability, and the steps that water systems can
take to address these uncertainties. This document is intended for small and medium-sized public water
systems as well as technical assistance providers and state programs that support or regulate these
systems.
Introduction
Public water systems supply over 44 billion gallons of water per day to supply the domestic water needs of
the majority of Americans.1 This accounts for the third largest withdrawal of fresh water in the United States
(13%) following thermoelectric power (49%) and irrigation (31%). Public water supply use increased from 14
billion gallons in 1950 to 29 billion gallons in 1975 and exceeded 44 billion gallons in 2005.'
As the nation's population continues to grow, so do the demands on our freshwater resources and the public
water suppliers responsible for providing a safe and reliable water supply to consumers. Water managers in
36 of 47 states responding to a survey anticipate water shortages in the next 10 years under normal climate
conditions."
Water shortages can also be exacerbated by the unequal distribution of available fresh water over space and
time. Drought, increased pollution and other short or long-term climate impacts that change or degrade
water quality as well as increased competition for raw water resources add other constraints to providing a
safe, reliable water supply.
What are the potential impacts to water resources from climate change?
Regional climate differences, natural variations in weather patterns, and seasonal changes in supply and
usage all contribute to water availability and variability constraints. Weather oscillations may be exacerbated
by climate change and typically impact water quality as well as quantity. Some of the projected effects of
climate change on fresh water resources include the following:1"
1. Increased frequency and duration of droughts. The increased frequency and duration of droughts may
result in diminished fresh water supplies in both the short- and long-term. Drought effects can be especially
critical in the more arid Southwest and Mountain West regions of the United States; however, other regions,
such as the Southeast, are experiencing more frequent and severe droughts (see Figure 1). Ensuring
adequate supplies of water during droughts that reduce aquifer recharge and reservoir storage is a critical
concern for most water systems. Reduced rainfall in drought conditions can contribute to increased water
demand from customers. Extended drought conditions can result in raw water quality changes due to
changes in watersheds, lakes and reservoirs or salt water intrusion in coastal areas.
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U.S. Drought Monitor F8b7ai7J&2012
Intensity
I I DO Abnormally Dry
HI D1 Drought - Moderate
I I D2 Drought Severe
D3 Drought - Extreme
D4 Drought - Exceptional
r*' De*neates dominant impacts
S = Short-Term, typlealy «6 months
(e.g. agriculture, grasslands)
L = Long-Term, typicaly >6 months
(e g, hydrology, ecology)
rzz>
The Drought Monitor focuses on broad-scale conditions.
Local conditions may vary. See accompanying text summary
for forecast statements
USDA
http://droughtmonitor.unl.edu/
Released Thursday, March 1, 2012
Author: Mark Svoboda. National Drought Mitigation Center
Figure 1. U.S. Drought Monitor
2. Increased frequency and severity of significant wet weather events. Heavier, more extreme precipitation
from tropical hurricanes and inland storms will likely increase the risks of flooding. Floods can pose serious
threats to the health and safety of communities and the drinking water infrastructure on which they depend.
In addition, significant wet weather events and flooding can negatively alter influent water quality. Intense
rainfall and stormwater runoff may result in changes in both water quality (turbidity, pH, alkalinity) and
watershed conditions. These events can also result in increases in water pollutants such as nutrients,
pesticides, and fecal matter from farms; chemicals from industrial processes; and fuel and organic
compounds from vehicles and roadways that may require changes to water treatment practices to continue
to meet drinking water standards.
Natural disasters, such as hurricanes and fires, can exacerbate flood or drought conditions. For example, fires
are common in much of the Western U.S. during the late summer drought period. Loss of forests and other
vegetation due to fire can also lead to changes in water availability and variability in water quality. Severe
weather can result in widespread and long duration power outages that can affect the capacity to treat or
deliver water.
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3. Changes in the timing of stream flow. Changes in the
timing of stream flow (higher high flows and lower low
flows) alter the volume of available water and increases
water pollution problems. In the Northwest, climate
change may cause more winter precipitation to fall as rain
instead of snow. This change results in higher velocity
stream flows and decreased winter snowpack, effectively
reducing stored water quantity. Further, higher stream
velocities may increase streambed erosion leading to
higher source water turbidity or may result in other water
quality changes that impact water treatment processes.
Warmer air temperatures may result in warmer stream
water, which holds less dissolved oxygen, and may foster harmful algal blooms in receiving water bodies.
4. Decreased freshwater availability due to saltwater intrusion from rising sea levels. Rising sea levels will
likely move ocean and estuarine shorelines inland and alter the tidal range of coastlines and rivers. In
addition, coastal areas may incur increased damage from floods and storms and changes in the timing and
volume of freshwater runoff. These phenomena will have a strong influence on coastal water supplies as
they change from freshwater to brackish or salt water and may require changes in water treatment
processes.
What steps should public water systems take?
Predictions associated with the timing and severity of climate change impacts, particularly when they are
scaled to the local level, and are still imprecise. As a result, planning for an uncertain future with the many
potential consequences of climate change can be challenging. However, there are many "no regrets"
measures to address water availability and variability issues. "No regrets" measures are measures that can
increase the resilience and adaptive capacity of a water system to reduce vulnerability regardless of the
direction and extent of future climate changes. Many of these steps are also good industry practices that
water systems should adopt regardless of potential climate change impacts and the uncertainty associated
with those impacts.
EPA's Climate Ready Water Utilities (CRWU) initiative assists drinking water, wastewater, and stormwater
utilities in understanding and adapting to climate change impacts. CRWU provides a number of practical and
easy-to-use tools (referenced below) that translate complex climate projections into accessible and
actionable information for utilities to use. This information helps utility owners and operators better prepare
their systems for the impacts of climate change.
The following steps will help public water systems think through their water availability and variability issues,
be more effective stewards of our freshwater resources and prepare for potential climate change impacts.
These steps include improving system knowledge, reducing water loss, diversifying the water supply and
management "portfolio'"v and looking at water system infrastructure more expansively to include green
infrastructure/ It is important to note that there is no "one size fits all" approach to addressing water
availability and variability. A public water system's vulnerability to these issues and the solutions available to
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them will vary based on the complexity of the system, the community's size and composition as well as local
conditions.
*~ RESOURCE: CRWU Adaptive Response Framework.
http://water.epa.gov/infrastructure/watersecurity/climate/upload/epa817fl2009.pdf
Step 1 - Improve system knowledge. Local, system-level knowledge is the best way to assess current water
availability and variability concerns and to begin to prepare for potential future changes. Table 1 provides
information needs and questions a water system should be able to answer or should work toward answering,
as well as state and local resources for gathering this data.
Table 1. Information Needs and Resources for Improving Local Knowledge
Does supply vary by season?
During which time of year is
water most abundant?
Does the intensity of
precipitation vary?
Is supply affected by drought?
How frequent are drought
events?
What is the average duration of
drought events?
Does the water system
experience frequent water
shortages or supply emergencies?
Is the system vulnerable to
quality changes at the source?
Do changes in water quantity
drive changes in quality?
How does the system currently
manage changes in water quality
and/or quantity?
If those changes were
exacerbated, could the system
manage? How?
_L
Estimated service population
Estimated service area (square
miles)
Types and number of service
connections
Total system demand (design)
Average-day demand
Peak-day demand
Rate structure
Metered sales
Unmetered sales
Water loss (apparent and real
losses)
Does the water system have
substantial water loss?
Is the system experiencing a high
rate of population and/or
demand growth?
Is the system forecasting future
demand?
Is the system planning for
substantial improvements or
additions?
Is the system in a designated
critical water supply area?
Ongoing and historical source
water monitoring records: stream
flows, surface water levels,
well/groundwater table
measurements
State source water assessments
Water conservation plans
Drought or emergency planning
documents
Capital, facility, or supply plans
Periodic supply assessments
State capacity reports
Sanitary survey results
Local climate data
*- RESOURCE: Climate Ready Water Utilities (CRWU) Adaptation Strategies Guide
http://water.epa.gov/infrastructure/watersecurity/climate/upload/epa817kll003.pdf
* RESOURCE: CRWU Climate Resilience Evaluation and Awareness Tool (CREAT)
http://water.epa.gov/infrastructure/watersecurity/climate/upload/epa817kl2002.pdf
* RESOURCE: Climate Ready Water Utilities Toolbox.
http://www.epa.gov/safewater/watersecurity/climate/toolbox.html
* RESOURCE: 1998 EPA Water Conservation Plan Guidelines. http://www.epa.gov/WaterSense/pubs/guide.html
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*~ RESOURCE: Alliance for Water Efficiency, AWE Resource Library, Water Conservation Programs.
http://www.allianceforwaterefficiency.org/Water Conservation Programs Library Content Listing.aspx
* RESOURCE: National Environmental Services Center, http://www.nesc.wvu.edu/futurewater/
*~ RESOURCE: Control and Mitigation of Drinking Water Losses in Distribution Systems.
http://water.epa.gov/tvpe/drink/pws/smallsystems/upload/Water Loss Control 508 FINALDEc.pdf
*~ RESOURCE: American Water Works Association (AWWA) Free Water Audit Software© available at:
http://www.awwa.org
* RESOURCE: U.S. Census, http://www.census.gov/
* RESOURCE: U.S. Drought Monitor, http://droughtmonitor.unl.edu/
Step 2 - Identify water losses and invest in water efficiency measures. Public water systems depend on
abundant water sources of the best quality possible to meet increasing water demands and resources to
locate, develop, treat and maintain these sources. When insufficient availability or extreme variability
becomes an issue, a water system may increase the capacity of the existing water treatment facility, find and
develop another source or buy additional water from another water system. However, finding a new, reliable
source of adequate quality may not always be an available option and
capital improvement projects can be prohibitively expensive. One
option is to take steps to reduce water demand. This can be
accomplished by both supply-side water efficiency and end-user
conservation. On the supply-side, a public water system should
investigate system processes and operations and determine if there is
any way to save water internally (for example modifying backwash
processes and reducing distribution system losses). This also may be a
good time to develop and implement a water loss control and
accounting program at the public water system if one is not already in
place. Such a program may be able to defer development of new sources and reduce or eliminate the need
to supplement supply from another water system. On the demand side, a water system can work with
consumers to reduce demand through several means including: price signaling/conservation pricing; free
water audit programs for large volume users and residential customers; retrofit/replacement programs to
repair or replace old toilets and fixtures with new, more water efficient models; and changing customer
behavior through public education and outreach (advertising campaigns, water-bill inserts, etc.).
* RESOURCE: CRWU Adaptation Strategies Guide Energy Management Sustainability Brief
http://water.epa.gov/infrastructure/watersecurity/climate/upload/epa817kl3001.pdf
* RESOURCE: EPA's Energy Use Assessment Tool
http://water.epa.gov/infrastructure/sustain/energy use.cfm
*- RESOURCE: Water Audits for Public Water Systems (EPA 816-F-13-002).
http://water.epa.gov/type/drink/pws/smallsvstems
*- RESOURCE: Water Efficiency for Public Water Systems (EPA 816-F-13-003).
http://water.epa.gov/type/drink/pws/smallsvstems
*- RESOURCE: Control and Mitigation of Water Losses in Distribution Systems. (EPA 816-R-10-019).
http://www.epa.gov/safewater/pws/pdfs/analysis wa-03 water loss doc final draft v62.pdf
* RESOURCE: WaterSense http://www.epa.gov/watersense/
* RESOURCE : AWWA Free Water Audit Software© http://www.awwa.org/resources-tools/water-
knowledge/water-loss-control.aspx
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Step 3 - Assess and plan. After assessing its potential vulnerabilities to climate change and water availability
and variability using Steps 1 and 2 above, a water system can analyze various scenarios and identify
solutions. Increasing water and energy efficiency, implementing conservation and demand management
programs, developing emergency preparedness plans for floods and droughts and protecting green
infrastructure are all examples of "no regret" solutions. These solutions can address multiple conditions that
impact the public water system and have immediate economic and environmental benefits, in addition to
addressing future uncertainty/1
* RESOURCE: Climate Ready Water Utilities -GREAT, http://water.epa.gov/infrastructure/watersecurity/climate/
* RESOURCE:: CRWU's Preparing for Extreme Weather Events: Workshop Planner for the Water Sector
http://water.epa.gov/infrastructure/watersecurity/climate/
Step 4 - Diversify the water supply and management portfolio. Diversification is key to increasing resilience
and adaptive capacity. A financial investment portfolio, for example, will balance short-term and long-term
objectives by diversifying its investments. Similarly, a water system can diversify its water supply and
management portfolio by balancing short-term and mid-term strategies, such as demand management
efforts, with long-term strategies like the development of new storage and transfer programs/" The need to
leverage innovative technologies and alternative water supply is also important as water supplies are
stressed by growing populations, the impacts of
climate change and greater competition of raw water
resources. For example, an increasing number of
communities are viewing stormwater and wastewater
as a resource rather than a waste. As source water
becomes scarcer and treatment technology improves,
desalinization is also becoming a more attractive
option for some communities. A summary
diversification options are listed in Table 2.
of
*- RESOURCE: U.S. EPA's Web site on Water
Availability.
Table 2. Water Diversification Options
Protect existing sources
n Source water protection
n Watershed protection
n Watershed partnerships
Manage storage to complement anticipated
supply
n Large storage for multi-year variation
n Small storage sufficient for annual
variation
Water efficiency of system operations
n Metering
n Water accounting
n Leak detection and repair
n Pressure management
Partnerships with other systems
n Interconnection for emergency use
n Bulk water purchases
Green infrastructure/stormwater
catchment
Water reuse/recycling for non-potable use
Desalinization
[http://water.epa.gov/infrastructure/sustain/availability wp.cfml
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Step 5 - Look for opportunities to include green infrastructure. Examples of green infrastructure include
wetlands, forests, parks, rain gardens, green roofs and porous pavement. Green infrastructure absorbs
runoff, reducing flood potential and improving water quality. The runoff absorbed by wetlands and forests is
slowly released at a later time, reducing the variability of the water supply by recharging aquifers and
maintaining baseflow in streams/1" Often termed "total water management" or "integrated resource
planning," this holistic approach to managing water
resources is cost-effective and has multiple
benefits. In addition, many communities are
beginning to look at stormwater as a valuable
resource that can be captured or injected into the
ground, while ensuring appropriate protection of
aquifers, to restore depleted aquifers. Solutions
range from retention ponds, to rain barrels and
cisterns, to a whole suite of strategies for
infiltrating stormwater where it falls, rather than
channeling it away through piped systems. Fostering these approaches in your community can reduce the
demands on your drinking water system, extend the life of water supplies and have numerous other
environmental benefits.
* RESOURCE: EPA's Web site on Green Infrastructure.
http://cfpub.epa.gov/npdes/home.cfm7program id=298
* RESOURCE: EPA Workshop on the Challenges of Green Infrastructure.
http://www.epa.gov/region07/newsevents/events/proceedings/om green infrastucture/index.htm
* RESOURCE : CRWU Adaptation Strategies Guide Green Infrastructure Sustainability Brief
http://water.epa.gov/infrastructure/watersecurity/climate/upload/epa817kll003.pdf
ADDITIONAL RESOURCES
What funding options are available?
The Drinking Water State Revolving Fund (DWSRF) can provide low-interest loans for a variety of energy efficiency
and water efficiency projects. States are encouraged to continue to use their DWSRF capitalization grant to fund green
drinking water projects to address green infrastructure, water and energy efficiency improvements and other
environmentally innovative activities. In FY2010 and FY2011, states were required to use a minimum of 20 percent of
their capitalization grant for green projects (also known as the Green Project Reserve or GPR). For the FY2012
capitalization grant, designating green projects is at the discretion of the state. Examples of fundable green projects
include energy audits, equipment upgrades, leak detection equipment, water meter installation and installation of
water efficient devices. Other improvements, which in FY2010 and FY2011 required the development of a business
case to be designated for GPR, include retrofit or replacement of pumps and motors with high efficiency motors,
replacement or rehabilitation of distribution lines or installing Supervisory Control and Data Acquisition (SCADA)
systems. These improvements may also still be eligible for funding even if they are not designated for GPR. Drinking
water systems should contact their state DWSRF programs to find out more about the state's priorities and funding
options.
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RESOURCE: DWSRF Green Project Reserve 2010 Guidance, http://www.epa.state.il.us/water/financial-
assistance/publications/green-project-reserve-guidance.pdf
RESOURCE: DWSRF Contacts by State.
http://water.epa.gov/Grants Funding/DWSRF/upload/DWSRFCONTACTS.pdf
RESOURCE: EPA FEDFUNDS
http://water.epa.gov/infrastructure/watersecurity/funding/fedfunds/
RESOURCE: EPA/HUD/DOT Sustainable communities partnership
http://www.sustainablecommunities.gov/
RESOURCE: Green Infrastructure funding sources.
http://water.epa.gov/infrastructure/greeninfrastructure/gi funding.cfm
RESOURCE: USDA Rural Development Grants .
http://www.rurdev.usda.gov/RD Grants.html
State drinking water programs can play various roles in the promotion of water availability and variability
issues including providing input and/or coordinating activities of other agencies, organizations and programs;
fostering coordination and partnerships; developing new laws and policies; providing technical assistance to
water utilities; and promoting tools and information sharing. The Association of State Drinking Water
Administrators (ASDWA) released a white paper on the topic in February, 2009, that outlines an assortment
of state strategies and plans, legal/regulatory frameworks for water withdrawals, water
conservation/efficiency policies and public education programs.IX State strategies to promote water
availability and variability may include Climate Action Plans or Growth and Development Plans, Water
Management or Drought Plans, or regulations, permitting or water reuse programs. According to a recent
comparison of water loss policy by state, water loss policies were found in 33 states and 26 states have
water loss standards."
* RESOURCE: ASDWA National Analysis of State Drinking Water Programs in the Areas of
Water Availability, Variability and Sustainability (WAVS).
http://www.asdwa.org/ data/n 0001/resources/live/WAVS%20Report%20FINAL.pdf
* RESOURCE: CRWU- Preparing for Extreme Weather Events: Workshop Planner for the
Water Sector, http://water.epa.gov/infrastructure/watersecurity/climate/
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Case studies
GEORGIA WATER COUNCIL. The Georgia Water Council has adopted the state's first comprehensive water-use
plan to address severe drought conditions. Representatives from local and state government and the
Georgia American Water Works Association and National Rural Water Association state affiliates comprise
the membership of the Council and were directly involved in developing the state's plan. The plan calls for
the establishment of 11 regional management districts that will oversee the measurement and withdrawals
of water from lakes, rivers and aquifers. The estimated cost to gather data and create regional water plans
for the districts over the next three years is approximately $30 million. The regional water plans will likely
involve local governments and include growth and development strategies based on water availability.
TEXAS WATER DEVELOPMENT BOARD (TWDB). The TWDB's mission is to provide leadership, planning, financial
assistance, information, and education for the conservation and responsible development of water for Texas.
Texas was the first state in the United States to pass legislation requiring water utilities to submit water
audits (initially every five years) to the TWDB, to promote water conservation to meet the water demands of
Texas' growing population, while protecting its natural resources. The TMDB has also developed a water
conservation best practices guide. Over 2,000 completed water audits were submitted to TWDB for calendar
year 2005.
STATE OF WASHINGTON. The State of Washington passed comprehensive legislation promoting greater water
use efficiency. Major provisions of the legislation include requiring water utilities to meet a distribution
system leakage standard of less than 10 percent, establish goals for their customers, create a water use
efficiency plan and submit an annual report to measure progress, and install meters on all customer service
connections within 10 years of the 2004 legislation. Water utilities must also install meters on all customer
service connection by 2017.
*~ Case Study on Water Reuse: El Paso Texas, http://www.epwu.org/reclaimed water/rwater.htmI
*~ Case Study on Desalinization: Tampa Bay-Seawater Desalination.
http://www.tampabaywater.org/facilities/desalination plant/index.aspx
Government Resources
National databases on surface water and ground water resources are available online and may be helpful in
evaluating your water system's source water viability.
* RESOURCE: USGS Water Data Discovery features water maps including droughts, floods, streamflow, and
ground water response to climate change, http://water.usgs.gov/
* RESOURCE: The National Hydrography Dataset (NHD) is a comprehensive set of digital spatial data
representing the surface water of the United States These data are designed to be used in general mapping
and in the analysis of surface-water systems using geographic information systems (GIS). http://nhd.usgs.gov/
*- RESOURCE: Ground Water Atlas of the United States, http://pubs.usgs.gov/ha/ha730/
* RESOURCE: Climate Assessment Tool (CAT) element of the BASINS water modeling program can be used to
support assessment of climate-related water resources impacts and program decisions.
http://water.epa.gov/scitech/datait/models/basins/b3webdwn.cfm
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Additional resources available to assist water systems in addressing water availability and variability include:
* RESOURCE: U.S. EPA Climate Change Program.
http://www.epa.gov/climatechange/effects/water/availability.html
*- RESOURCE: CRWU: Final Report of the National Drinking Water Advisory Council.
http://water.epa.gov/drink/ndwac/climateccchange/index.cfm
*~ RESOURCE : GREAT: EPA developed GREAT, a software tool to assist drinking water and wastewater utility
owners and operators in understanding potential climate change threats and in assessing the related risks at
their individual utilities, http://water.epa.gov/infrastructure/watersecurity/climate/creat.cfm
* RESOURCE: Community-Based Water Resiliency Tool. EPA 817-C-11-001.
http://water.epa.gov/infrastructure/watersecurity/techtools/cbwr.cfm
1 Kenny, J.F., Barber, N.L, Hutson, S.S., Linsey, K.S., Lovelace, J.K., and Maupin, M.A. 2009. Estimated use of water in the United
States in 2005: U.S. Geological Survey Circular 1344, 52 p. http://pubs.usgs.gov/circ/1344/pdf/cl344.pdf
" U.S. Government Accounting Office. 2003. FRESHWATER SUPPLY: States' Views of How Federal Agencies Could Help Them Meet
the Challenges of Expected Shortages, http://www.gao.gov/htext/d03514.html
111 Intergovernmental Panel on Climate Change (IPCC). 2007. IPCC: Climate Change 2007: Impacts, Adaptation, and Vulnerability.
Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate. Cambridge
University Press, Cambridge, United Kingdom, 1000 pp. http://www.ipcc.ch/publications and data/ar4/wg2/en/contents.html
IV Climate Ready Water Utilities Working Group, 2010. Final Report of the National Drinking Water Advisory Council; December 9,
2010. http://water.epa.gov/drink/ndwac/climatechange/upload/CRWU-NDWAC-Final-Report-12-09-10-2.pdf
v Climate Ready Water Utilities Working Group, 2010. Final Report of the National Drinking Water Advisory Council; December 9,
2010. http://water.epa.gov/drink/ndwac/climatechange/upload/CRWU-NDWAC-Final-Report-12-09-10-2.pdf
Vl Water Utility Climate Alliance, 2010. Decision Support Planning Methods: Incorporating Climate Change Uncertainties into Water
Planning, www.wucaonline.org/assets/pdf/actions whitepaper 012110.pdf
v" Miller, K., Yates, D., 2005. Climate Change and Water Resources: A Primer for Municipal Water Providers. Water Research
Foundation.
Climate Ready Water Utilities Working Group, 2010. Final Report of the National Drinking Water Advisory Council; December 9,
2010. http://water.epa.gov/drink/ndwac/climatechange/upload/CRWU-NDWAC-Final-Report-12-09-10-2.pdf
ASDWA(2009). National Analysis of State Drinking Water Programs in the Areas of Water Availability, Variability and
Sustainability (WAVS). http://www.asdwa.org/ data/n 0001/resources/live/WAVS%20Report%20FINAL.pdf
Beecher, Janice A. 2002. Summary of State Agency Water Loss Reporting Practices. Final Report to the American Water Works
Association.
Office of Water (4606M) EPA 816-F-13-005 July 2013
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