&EPA
United States
Environmental Protection
Agency
EPA's 2007 Drinking Water Infrastructure Needs
Survey and Assessment
Summary In 2007, the U.S. Environmental Protection Agency (EPA) conducted its fourth Drinking Water
Infrastructure Needs Survey and Assessment (D WINS A or Assessment). The purpose of the Assessment is to
document the 20-year capital investment needs of public water systems that are eligible to receive Drinking
Water State Revolving Fund (DWSRF) monies — approximately 52,000 community water systems and 21,400
not-for-profit noncommunity water systems. As directed by the Safe Drinking Water Act (SDWA), EPA uses
the results of the survey to allocate DWSRF funds to the states.
Total National 20-Year Need fin billions of
January 2007 dollars)
System Size and Type
Large Community Water Systems*
(serving over 100,000 persons)
Medium Community Water Systems*
(serving 3,301-100,000 persons)
Small Community Water Systems
(serving 3,300 and fewer persons)
Not-for-Profit Noncommunity Water Systems1'
Total State Need
American Indian and Alaska Native Village
Water Systems1
Costs Associated with Proposed and Recently
Promulgated Regulations
Total National Need
$116.3
$145.1
$59.4
$4.1
$324.9
$2.9
$7.0
$334.8
Note - numbers mav not total due to rounding,
* "Large" and "medium" systems are defined differently for this
Assessment than previous Assessments. See Appendix A in the
DWINSA report for more information.
t Based on 1999 Assessment findings adjusted to 2007 dollars.
Needs were adjusted from 1999 to 2007 dollars.
How Was the Assessment Conducted? The approach for
the Assessment was developed by EPA in consultation
with a workgroup consisting of representatives from EPA
regions and each state. The Assessment approach relied
primarily on a random sample survey. A questionnaire was
used to collect documented needs and costs.
Approximately 3,250 public water systems participated in
the survey. EPA mailed questionnaires to all 584 of the
nation's large water systems (serving more than 100,000
persons) and 2,266 medium systems (serving between
3,301 and 100,000 persons). Approximately 97 percent of
the large systems and 92 percent of the medium systems
returned the questionnaire. For small community water
systems (serving fewer than 3,300 people), EPA
contracted water system professionals to conduct in-person
site visits to 600 small systems. These field surveys
served to accurately assess the infrastructure investment
needs of small systems.
The needs of not-for-profit noncommunity systems and
systems serving American Indian and Alaska native
villages are based on the findings of the second DWINSA.
What Is the Total Need? The survey found that the total nationwide infrastructure need is $334.8 billion for
the 20-year period from January 2007 through December 2026. American Indian and Alaska native village
systems represent $2.9 billion of the total national need. It
is important to note that the scope of the survey is limited to
those needs eligible to receive DWSRF assistance—thus
excluding capital projects related solely to dams, raw water
reservoirs, future growth, and fire protection.
Total 20-Year Need by Project Type (in billions
of January 2007 dollars)
Treatment
$75.1
How is the Need Broken Out by Category? With $200 8
billion in needs over the next 20 years, transmission and
distribution projects represent the largest category of need.
This result is consistent with the fact that transmission and
distribution mains account for most of the nation's water
infrastructure. The other categories, in descending order of
need are: treatment, storage, source and a miscellaneous
category of needs called "other."
Transmission
and Distribution
$200.8
Source
$19.8
Note: Numbers may not total due to rounding.
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How Does the 2007 Need Compare to the Other Assessments? The total national need of $334.8 billion
reported by this Assessment is similar to the result of the 2003 Assessment ($331.4 billion when adjusted to
2007 dollars). The 2003 and 2007 estimates differ greatly from the 1995 and 1999 Assessments, which
estimated a need of $200.4 billion and $198.2 billion (when adjusted to 2007 dollars), respectively. EPA
believes the 2007 Assessment continues the success of the 2003 effort in better capturing previously under-
reported needs for rehabilitation and replacement of existing infrastructure. However, the 2007 DWINSA was
specifically designed to further improve consistency across states and water systems in the methodologies for
estimating infrastructure investment need.
The large magnitude of the national need reflects the challenges confronting water systems as they deal with an
infrastructure network that has aged considerably since these systems were constructed, in many cases, 50 to
100 years ago.
How Does the Need Vary by System Size? The nation's medium sized water systems (serving between 3,301
and 100,000 people) account for the greatest share, $145.1 billion, of the total national need. Large and small
systems also have substantial needs of $116.3 billion and $59.4 billion, respectively. The small system need is
relatively high when compared to the fact that these systems serve 9 percent of the total national population.
This reflects the challenges these small systems often face. Not-for-profit noncommunity water systems have
$4.1 billion of need.
What is the Regulatory Need? Although all of the infrastructure projects in the survey promote the public
health objectives of the SDWA, only $52.0 billion, or 16 percent of the total national need is directly
attributable to compliance with specific SDWA regulations. The majority of projects are needed to ensure the
continued provision of safe drinking water.
The total need for obtaining and maintaining compliance with existing regulations is $45.0 billion. The
remainder of the regulatory-related need is for compliance with proposed and recently promulgated regulations
including $2.2 billion for the treatment needs under the Long Term 2 Enhanced Surface Water Treatment Rule,
$1 billion for the Stage 2 Disinfectants/Disinfection Byproducts Rule, $0.4 billion for the Ground Water Rule,
and $3.3 billion for the Radon Rule.
How Credible are the Findings? In order to produce an estimate of need nationally and for each fully
surveyed state (some states were given the option of a partial survey), EPA set a statistical confidence level of
95 percent with a precision target of+/- 10 percent. To meet this target, all large systems were surveyed, an
adequate number of medium systems were randomly selected in each fully surveyed state, and a national
sample of small systems was selected.
In planning for the 2007 Assessment, EPA and the states reached a consensus on consistent policies regarding
replacement and rehabilitation assumptions and documentation requirements to support projects allowable for
the survey. EPA's quality assurance reviews included significant efforts to ensure policies were followed by all
states.
Where Can I Obtain More Information? Information on the Drinking Water Infrastructure Needs Survey
and Assessment: Fourth Report to Congress is available from the Safe Drinking Water Hotline at 1-800-426-
4791. EPA will post the electronic files on the Office of Ground Water and Drinking Water home page at
www.epa.gov/safewater/needssurvey. Reprints of the report are available to the public through the National
Service Center for Environmental Publications (NSCEP) website at www.epa.gov/nscep/.
Office of Water (4606M) EPA 816-F-09-003 February 2009 www.epa.gov/safewater
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