Protecting Drinking Water
Sources
SAFE DRINKING WATER ACT • 1974-2004 • PROTECT OUR HEALTH FROM SOURCE TO TAP
The 1996 Amendments to the Safe Drinking Water
Act (SDWA) took a major new step in drinking
water protection by mandating that states perform
a source water assessment for each public water
system. States are responsible ^^^^^^^^^_
for completing assessments for
public water systems in major
metropolitan areas, small towns,
schools, restaurants, and other
public facilities that have a well or
surface water supply. (Private wells
are not included in this effort.)
After a state's Source Water
Assessment Program (SWAP)
is approved by the United
States Environmental Protection
Agency (US EPA), the state has
two years, with a possible 18
months extension, to conduct
an assessment for each public
water system and make these
assessments available to the public. US EPA has
approved 52 SWAP programs. States must complete
all the assessments in the state no later than 3 years
after US EPA approves the programs.
The source water assessment programs established
by each state differ, depending on the nature and
threats to the water resources and the drinking water
program priorities in a particular state. However,
each assessment program must include four major
elements:
• delineating (or mapping) the source
water protection areas
• conducting an inventory of potential
sources of contamination in those areas
• determining the susceptibility of public
water systems to those contamination
sou rces
• releasing the results of the
determinations to the public
Following successful completion of these elements for
each assessment, communities can use the resulting
information to identify priority actions for protecting
their drinking water sources.
Source Water Assessments
The four assessment steps are described in more detail
below.
Step 1:
Delineate the
sou rce water
assessment area
For each
grou nd water
well or surface
water system
that supplies
public drinking
water, states
must delineate
and map the
boundaries of
each protection
area.
For ground water systems, states commonly use
available information about ground water flow and
recharge to determine the source water protection
area around a well or well field.
For surface water systems drawing water from a
stream, river, lake, or reservoir, the land area in
the watershed upstream of the intake is identified
on a map. A topographic map is used to identify
the perimeter of the area that provides water to the
water system's intake. Some states plan to divide the
watershed area into segments—areas that are closest
to the intake where most types of contamination
sources may be found to be significant, and other
more distant areas. The entire watershed area up to
the state's boundaries is required to be delineated
and mapped, but the level of detail in the inventory
of potential pollution sources and the susceptibility
determination can vary in the different segments.
Coordination across state boundaries is encouraged
where appropriate.
Step 2: Conduct an inventory of potential sources of
contamination
In the second step of an assessment, the state
identifies the potential sources of pollutants that
could contaminate the water supply. This inventory
-------
usually results in a list and a map of facilities and
activities within the delineated area that may release
contaminants into the underground water supply
(for wells) or the watershed of the river or lake (for
surface water sources).
Some examples of the many different types of
potential pol I utant sou rces include landfills,
underground or above-ground fuel storage tanks,
residential or commercial septic systems, urban
runoff from streets and lawns, farms and other
entities that apply pesticides and fertilizers, and
sludge disposal sites.
Step 3: Determine the susceptibility of the water
supply to contamination
In the third step—the susceptibility determination
—the state combines the inventory results with other
relevant information to decide the likelihood of
contamination of the water supply by the identified
significant potential sources of contamination.
This critical step makes the assessments useful for
communities. It helps local decision-makers consider
priority approaches for protecting the drinking water
supply from contamination. Some states prioritize
the potential for contamination from the specific
potential contamination sources or to individual
chemicals that could pollute the water. Other states
assign a susceptibility ranking of high, medium, or
low to the water sources.
Step 4: Provide the assessment results to the public
After the state completes the assessment for a
particular water system, it will summarize the
information for the public. Such summaries will
help communities better understand the potential
threats to their water supplies and identify priority
needs for protecting the water from contamination.
This summary information must be included in water
systems' Consumer Confidence Reports (annual
water quality reports). Local communities, working
in cooperation with local, regional, and state
agencies, can use the information gathered through
the assessment process to create a broader source
water protection program to address current and
future threats to the quality of their drinking water
supplies.
Source Water Protection
While source water protection was not specifically
mandated by SDWA, US EPA and its partners
encourage states, tribes, and communities to use the
information from source water assessments to protect
the delineated source water protection areas from
identified pollution sources of major concern. Using
a partnership approach, community groups and local
officials can plan how to best manage those identified
potential sources and prevent new contaminant threats
in the source water area.
Many source water protection areas will include
multiple jurisdictions, i.e., the city or county where the
source water intake or wellhead is located, and other
towns, counties, or states upstream or upgradient from
the public water system. Local political authorities
may be able to adopt protection measures within
their jurisdiction, but to achieve effective protection
beyond their boundaries, they will usually have to
work with neighboring jurisdictions or federal or state
authorities.
Communities use a wide array of different source
water protection methods to prevent contamination of
their drinking water supplies. One management option
involves regulations, such as prohibiting or restricting
land uses that may release contaminants in critical
source water protection areas. Along with regulations,
many communities hold local events and distribute
information to educate and encourage citizens and
businesses to recycle used oil, limit their use of
pesticides, participate in watershed cleanup activities,
and a multitude of other prevention activities. Another
aspect of a source water protection program can be
the purchase of land or the creation of conservation
easements to serve as a protection zone near the
drinking water source. For an effective protection
program, communities should consider using a variety
of prevention measures.
To assist their efforts to protect areas which surround
surface water sources of drinking water, local
authorities can look to Section 303 of the Clean
Water Act. This section requires each state to review
its water quality standards every three years. The
review must consider the "use and value" of the water
as a drinking water supply. States that adopt water
quality standards to protect all public water supplies
and prospective supplies can enforce these standards
under state and federal law to control pollution.
To augment local ground water protection efforts,
some states use ground water quality standards that
work much like the Section 303 program for surface
water. Some states also use a permit program to
regulate pollution that can contaminate ground
water. The federal Underground Injection Control
(UIC) program regulates the use of wells as a means
to dispose of waste, and the Resource Conservation
& Recovery Act (RCRA) regulates the management
of hazardous and non-hazardous waste that can
contaminate ground water.
For More Information:
For further information on your state's source water
assessment program and how to participate, contact
the agency in your state that is managing the program.
Call the Safe Drinking Water Hotline at 1-800-426-
4791, or visit the safewater web site at www.epa.
gov/safewafer for more information, state contacts,
and links to other organizations that may be active
with source water protection in your area. Your local
water supplier may also have more information about
opportunities to become involved in the source water
assessment process. You can call the phone number on
your water bill or contact your local health department
for information on your water supplier.
Office of Water (4606)
www.epa.gov/safewater
EPA 816-F-04-032 June 2004
------- |