United States
Environmental Protection
Agency
The Drinking Water State Revolving Fund (DWSRF) program was established by the 1996 Safe Drinking Water Act (SDWA)
Amendments and authorizes grants to states to capitalize revolving loan funds. The states provide low-interest loans to eligible
systems for infrastructure improvements needed to ensure compliance with the SDWA and protect public health. The
DWSRF program can play a significant role in helping systems, especially small systems, meet the challenges of complying
with drinking water standards.
According to the Environmental Protection Agency's (EPA's) 1999 Drinking Water Infrastructure Needs Survey, the total 20-
year need for transmission and distribution projects is $83-2 billion. Transmission and distribution system needs account for
more than half of the infrastructure investments needed nationwide. This reflects the reality that the bulk of a water system's
assets are the pipes that move raw water from the source to the treatment plant and distribute treated water to the consumer.
Transmission and distribution pipes that should be replaced, rehabilitated, or enlarged are a serious threat to public health.
Rehabilitating and replacing transmission and distribution infrastructure can be costly. The DWSRF can provide assistance to
systems to help ease this burden, increase compliance, and protect public health.
The nation's transmission and distribution systems are aging and deteriorating. Pipes
89% of water systems serving have nfe les that can e from 15 to over 100 _ The ma:orit of the nation>s
more than 10,000 people believe Jo .„. ,• •, • , • , f
estimated 2 million miles or transmission and distribution pipes were laid after the
they should rehabilitate or
replace their pipes more often
1960s. As the pipes age, replacement needs will increase (see Figure 1).
Figure 1: Projected Annual Percentage of Transmission Lines
and Distribution Mains Requiring Replacement, 2000 - 2075
"Out of sight, out of mind" can explain why many water systems have neglected their
transmission and distribution systems. Unlike treatment plants and storage tanks (which are a central focus for systems trying
to meet applicable maximum contaminant levels (MCLs)), sub-surface pipe networks tend to receive little attention until they
fail. When a main breaks and disrupts service, the distribution system typically receives emergency localized maintenance
around the failure. These "patches" do little to address a system's long-term transmission and distribution problems.
Most water systems have a general idea of the condition of their delivery network, but detailed evaluation is time-consuming
and technologically challenging, especially for older systems. Pipes do not deteriorate at a constant rate. During the initial
period following installation, the deterioration rate is relatively slow. As pipes near the end of their life cycle, they begin to
deteriorate more rapidly, dramatically increasing the repair and upkeep expenses. In addition, the rate of deterioration of a
distribution system is not solely a function of age, but
rather a combination of factors including the characteris-
tics of the water, soil conditions, and climate. Some
Eastern cities in the United States have well functioning,
unlined cast iron pipes that are over 200 years old.
Other communities' cast iron pipes may last less than 20
years.
The purpose of transmission and distribution infrastruc-
ture is to convey sufficient quantities of water to con-
sumers while keeping the water free from new sources of
contamination. When a pipe ruptures or a valve does
not close properly, the pressure of the system can drop
and intrusion of contaminants can occur, putting water
consumers at serious risk. Even well-run water systems
with relatively new distribution systems can experience
water main breaks.
2.5%
0.0%
2000 2010 2020 2030 2040 2050 2060 2070
Year
Source: EPA Clean Water and Drinking Water Infrastructure Gap Analysis, 2002.
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A transmission and distribution system fails when the system is no longer able to transport water or potable water degrades to
the point at which the health of consumers is threatened. There are several means by which the transmission and distribution
system can fail (see Exhibit 1):
Two major pipe breaks caused an
outbreak of E. coli in Cabool,
Missouri from December 1989 to
January 1990. Four people died and
another 240 became sick from the
distribution system failure.
1.
2.
3-
External contamination from intrusion and permeation.
Contamination from transmission and distribution pipes.
Contamination from cross-connections and backflow.
Exhibit 1: Causes of Transmission and Distribution System Failures
FAILURE DEFINITION CAUSES/SOURCE CONTAMINATION
External Contamination
Intrusion
Permeation
The flow of nonpotable water into
mains through leakage points,
submerged air valves, faulty seals,
or other openings. The volume of
intrusion can range from milliliters to
hundreds of gallons.
The passage of external
contaminants through porous plastic
pipe.
• Main breaks
• Sudden changes in water demand or flow
• Uncontrolled pump starting or stopping
• Opening and closing of fire hydrants
• Power failures
• Fire flow (in systems with inadequate storage or
supply)
• Faulty joints
• Pipes below the water table
• Improper water main installation or repair
• Interaction of plastic pipes with substances in the
external environment
• Stagnation of water in localized areas
• Microbiological
• Chemical
• Excess disinfectants
• Loss of disinfectant residual
• pH & alkalinity instability
• Volatile organic
contaminants
• Vinyl chloride
• pH & alkalinity instability
Contamination from Infrastructure
Leaching
Nitrification
Corrosion
The dissolution of metals, solids,
and chemicals into drinking water.
Oxidation of nitrogen compounds to
nitrate or nitrite.
External or internal deterioration of
the chemical integrity of the piping
material.
• Aggressive water reacting with pipe linings
• Stagnation of water in localized areas
• Use of chloramines
• Presence of nitrifying bacteria and ammonia
• Stagnation of water in localized areas
• Microorganisms
• Reactions of pipe lining with water
• Stagnation of water in localized areas
• Metals
• Asbestos
• Nitrite and nitrate
• pH & alkalinity instability
• Loss of disinfectant residual
• Biofilm growth
• Chemical
• Biofilm growth
Contaminations from Cross-Connections and Backflow
Cross-
Connections
Backflow
Points in the distribution system
where nonpotable water can come
into contact with potable water,
providing a pathway for backflow of
nonpotable water into potable
supplies.
Either reduced pressure in the
distribution system (backs! phonage)
or the presence of increased
pressure from a nonpotable source
(backpressure) that reverses the flow
so nonpotable water flows into the
potable water system.
• Connection of heating/cooling, waste disposal, or
industrial manufacturing systems to potable water
supplies when the pressure in the external system
exceeds the pressure in the distribution system
• Intentional contamination
• Main breaks, pump failure, firefighting, or opening fire
hydrants for recreation in a system with inadequate
storage or supply
• Improperly operating valves, loose-fitting service
meter connections, surge or feed tank draining, a
sudden change in demand, hilly terrain, limited
pumping capacity, high customer demand, and power
loss
• Pressure transient (also called surge or water hammer)
• Intentional contamination
• Microbiological
• Chemical
• Excess disinfectants
• Loss of disinfectant residual
• pH & alkalinity instability
• Biofilm growth
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Contamination introduced into the transmission and distribution
network can cause many problems for a water system. EPA has
published several National Primary Drinking Water Regulations
(NPDWRs) that address public health issues related to potential
chemical and microbial contamination in the distribution system,
including the Total Coliform Rule, the Lead and Copper Rule, the
Surface Water Treatment Rule, and the Stage 1 Disinfectants and
Disinfection Byproducts Rule.
The Borough of Williamsburg has served its residents and parts
of neighboring Woodbury and Catherine Townships with its
water system for more than 90 years. In the 1980s, two reservoirs
used by the system had to be abandoned due to Giardia
contamination and the poor condition of the system's
transmission lines. Even after the reservoirs were abandoned,
the existing lines remained undersized and in poor condition,
resulting in pressure, flow, and leak problems in some areas. In
May 1997, Williamsburg received a $4.2 million DWSRF loan.
The project included the installation of a booster pumping station,
new storage tank, eight miles of mains, and the replacement of
every meter in the system. The project was completed in 1998. j
The most acute threat from transmission and distribution system
failure is that old pipe, weak and brittle from hard-to-detect internal or
external corrosion, will break, causing the pressure in the distribution
system to plummet. Any break or leak in a distribution system can
potentially draw chemical and microbial contaminants into the distribution system. Sewer pipes are often installed adjacent to
drinking water mains. Even short periods of exposure to acute contaminants, like bacteria and viruses, can threaten public
health. From 1981 to 1998, the Centers for Disease Control documented 57 waterborne disease outbreaks related to cross-
connections, resulting in 9,734 illnesses. The American Water Works Association estimates that 78% of all waterborne disease
outbreaks in recent history were caused by cross-connections and backflow.
Many homes in the six subdivisions served by
the Clinton Public Works Authority were served
by cast iron, dead end lines with leaded joints.
Clinton's problems included inadequate water
availability, stale water caused by dead-ends, and
lead contamination. A $644,000 DWSRF loan
financed the majority of the project, which
included: replacing existing substandard lines
with new PVC water lines; constructing a loop
trunk line to supply the area; and replacing fire
hydrants, valves, and appurtenances.
The 1999 Drinking Water Infrastructure Needs Survey determined that water
systems need to invest $83-2 billion by 2018 to improve the nation's drinking water
transmission and distribution infrastructure (see Figure 2). Transmission and
distribution infrastructure accounts for more than 55% of the total water infrastruc-
ture investment needed nationwide. At least $65-6 billion is needed immediately to
rehabilitate or replace pipes to adequately protect public health. As water systems
modernize their treatment capability, they are becoming increasingly aware of the
need to upgrade their distribution systems so that they can reliably deliver safe water.
This attention should continue to increase—EPA estimates the transmission and
distribution infrastructure need will be even greater after 2019 as more pipes and
valves reach the end of their useful life.
Rehabilitating and replacing transmission and distribution infrastructure can be costly because of the difficulty in accessing pipes
and valves that are below ground (and often under streets). The majority of water main replacement is still performed using
open-cut or open-trench methods. These methods maximize the public burden both in terms of cost and public nuisance.
Recent technological advances in trenchless technologies, which have become commonplace in Europe, are being considered by
more water systems across the country because they minimize the
need for excavation and can save 20 percent to 60 percent in
overall costs.
Besides infrastructure investment, there are many other actions
water systems can take to improve their transmission and distribu-
tion systems. Many threats can be minimized by modeling the
transmission and distribution network to identify problem areas,
inspecting the infrastructure for leakage and corrosion and the
plumbing of customers for cross-connections, and properly
selecting the materials used in the transmission and distribution
system infrastructure. In addition, water systems can utilize tools
such as facility improvement plans and asset management. By
developing a comprehensive strategic plan, a water system can
potentially improve the process for building, maintaining, and
improving its transmission and distribution infrastructure.
Figure 2: Total Transmission & Distribution Infrastructure
Need by System Size (in billions of 1999 $)
Q
"S
CWSs"
Serving
< 3,300
CWSs"
Serving
3,30! -50,000
Non-Profit American Indian
NCWSs"" & Alaska Natives
Source: EPA 7999 Drinking Water Infrastructure Needs Survey, 2001.
"CWSs = Community Water Systems
**NCWSs = Non-Community Water Systems
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States use DWSRF capitalization grant monies to provide low-
interest loans to publicly- and privately-owned public water systems
for infrastructure improvements needed to continue to ensure safe
drinking water. States may offer principal forgiveness, reduced
interest rates, or extended loan terms to systems identified by the
state as serving disadvantaged communities. States also have the
ability to reserve a portion of their grants (i.e., set-asides) to finance
activities that encourage enhanced water system management and
help prevent contamination problems through source water protec-
tion measures. Based on the Fiscal Year 2002 appropriation of $850
million, capitalization grants ranged from $8.0 million to $82.4
million per state.
Most capital projects needed to upgrade a transmission and distribu-
tion system—including replacing fragile water mains and worn-out
valves—are eligible for funding under the DWSRF (see Exhibit 2).
Consolidation and restructuring of systems can be a cost-effective
option for small systems that need massive infrastructure investment.
The DWSRF can fund consolidation, including situations where a
system is unable to maintain compliance for technical, financial, or
managerial reasons.
States can use set-aside funds from the DWSRF to assist systems
directly as well as to enhance their own program management
activities (see Exhibit 2). A state may use set-asides to make adminis-
trative improvements to the entire drinking water program, which
faces increased costs in ensuring the integrity of transmission and
distribution systems across the state. States can also train small
systems on how to better manage and maintain their water delivery
network, as well as provide technical assistance to help systems
identify the
Exhibit 2: Transmission and Distribution
Projects/Activities Eligible for DWSRF Funding
Eligible Under
Type of Project/Activity Infrastructure
Fund
Eligible Under
Set-Asides
Treatment
Pigging
Lining
Corrosion Control
Backflow Prevention Devices
Backup Power
Backup Pumps
Disinfectant Booster Stations
Flushing Hydrants
Surge Control Devices
Pump Replacement
Valve Replacement
Water Main Replacement
Water Main Expansion
Looping Dead-end Mains
Water Meters
System Consolidation
System Restructuring
Yes*
Yes**
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes***
Yes
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Yes
System Administrative Improvements
Hire Staff
Staff Training
Public Outreach
Monitoring
Rate Increase Process
No
No
No
No
No
No
Yes
Yes
No
Yes
State Administrative Improvements
Hire Staff
Staff Training
Public Outreach
Compliance Oversight
Enforcement
Pilot Studies
Sanitary Surveys
Distribution System Assessments
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Vemuomit
Vermont used $150,000 in Fiscal Year 1999 DWSRF set-aside
funds to contract with engineering firms to develop facility
improvement plans for 79 small water systems that serve less
than 500 people. On behalf of the state, a consultant helped
Kountry Trailer Park, serving 44 mobile homes in the town of
Bristol, identify ways to overcome the occasional bacteriological
and pressure related problems from which they had been
suffering. The consultant suggested installing several flushing
hydrants, replacing sections of main, and working with the
town to maintain an adequate disinfection residual at the park
entrance. The consultant also documented the costs and helped
identify potential sources of funding.
'Capital expenditures only.
"Structural lining only.
Must be owned and maintained by system.
most cost-
effective upgrade
strategy (i.e., replacement versus rehabilitation). In addition, states
can provide assistance to small systems to cover the costs of project
planning and design for infrastructure improvements.
Since the DWSRF program is managed by states, project and set-
aside funding varies according to the priorities, policies, and laws
within each state. Given that each state administers its own program
differently, the first step in seeking assistance is to contact the state
DWSRF representative, who can be found on the EPA DWSRF
website.
FOR MORE INFORMATION.
DWSRF Website:
http://www.epa.gov/safewater/dwsrf.html
Transmission & Distribution Fact Sheets:
http://www.epa.gov/safewater/tcr/tcr.html
Printed on Recycled Paper
General Information
SDWA Hotline
1-800-426-4791
EPA's Ground Water & Drinking
Water Website:
http://www.epa.gov/safewater/
Office of Ground Water and
Drinking Water (4606M)
EPA816-F-03-003
February 2003
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