September 4, 2019
Controlling Lead in Public Drinking Water Supplies
Communities nationwide are facing a range of issues
care programs and schools and establish a program to
associated with aging water infrastructure, including
remove lead-lined drinking water coolers (SDWA Part F).
detection of elevated lead levels in drinking water. In
affected communities, drinking water is a source of lead
Limiting Lead in Plumbing Materials
exposure. Other sources of lead exposure include lead-
In 1986, Congress amended SDWA to prohibit the use of
based paint and contaminated soil and dust from
plumbing (e.g., pipes or pipe fittings) that were not “lead-
deteriorated lead-based paint.
free,” which was defined at the time as solder and flux with
no more than 0.2% lead and pipes with no more than 8%
Nationally, the phaseout of leaded gasoline, lead-based
lead (P.L. 99-339). Congress authorized states to enforce
paint, and other regulatory controls have reduced lead
these provisions and authorized EPA to withhold a portion
exposures. Since the late 1970s, overall blood lead levels in
of grant funds from a state for failure to enforce these
children (ages one to five) have declined an estimated 94%.
requirements (SDWA §1417).
However, because of lead’s toxicity, even at low levels,
reducing lead exposures from drinking water and other
Congress expanded the lead prohibition to include fixtures
sources remains a public health priority.
in 1996 (P.L. 104-182) and reduced the allowable lead
content in “lead-free” plumbing materials in 2011 (P.L.
Sources of Lead in Drinking Water
111-380). Lead-free is now defined as no more than 0.25%
Unlike lead, most contaminants, when found in public
lead across wetted surfaces of plumbing materials. Many
water supplies, are detected and treated at the plant. Lead in
communities may still have older plumbing that contains
drinking water occurs primarily where water is corrosive
more lead than is allowed for newer materials.
and lead is leached from pipes, plumbing materials, and
fixtures (e.g., faucets). Corrosion is a chemical reaction
Regulating Lead in Public Water Supplies
between the water and the plumbing materials. Factors
SDWA authorizes states to assume primary responsibility
affecting corrosion include the water’s acidity, temperature,
for oversight and enforcement of public water system
water use patterns, and the presence or absence of
compliance with drinking water regulations. EPA, among
protective coatings of mineral deposits that can accumulate
other responsibilities, retains oversight authority over state
inside pipes, among others. Accordingly, controlling
programs. Public water systems can be owned and operated
corrosion has been the principal method used to keep lead
by private or public entities, including municipalities or
from leaching into public water supplies.
local governments.
The presence of leaded pipes and materials in community
EPA regulates lead in drinking water through the 1991
water systems and homes generally depends on the age of
Lead and Copper Rule (LCR), as revised. This rule replaced
the water system and residences. Before the 1950s, lead
a standard for lead in drinking water of 50 parts per billion
pipes, known as lead service lines (LSLs), were commonly
(ppb), which was measured where treated water enters the
used to extend water service from the water main under the
distribution system. Because lead or copper generally enters
street to a residence or other building inlet. A 2016 analysis
the water after it leaves the plant, the current LCR includes
estimated that the number of LSLs nationwide declined
a treatment technique, which primarily relies on corrosion
from approximately 10 million to 6 million over three
control and water quality and tap water monitoring. The
decades. Leaded plumbing materials (e.g., brass fixtures) in
LCR also establishes an action level, which is a screening
homes and buildings can also contribute to lead in drinking
tool (not an enforceable standard) for determining whether
water.
further actions are required.
Safe Drinking Water Act
Under the LCR, public water systems are required to
The Safe Drinking Water Act (SDWA) authorizes the U.S.
optimize and maintain treatment to control corrosion.
Environmental Protection Agency (EPA) to regulate the
Usually, corrosion control treatment involves adjusting the
quality of water delivered by public water systems. Under
water’s acidity to mitigate the treated water’s potential to
SDWA, Congress has addressed exposure to lead in
corrode lead from the water system or household plumbing.
drinking water using several approaches. These include (1)
Corrosion control treatment can provide a cost-effective
limiting lead in plumbing materials and fixtures (SDWA
way to control lead in drinking water, but maintaining
§1417) and (2) authorizing EPA to regulate contaminants,
control of corrosion is complex and requires consideration
such as lead, in public water systems through national
of factors such as source water quality and composition of
primary drinking water regulations (SDWA §1412).
distribution system and interior plumbing in individual
Further, Congress amended SDWA to address lead in child
properties. Further, actions to comply with other SDWA
drinking water regulations may increase the water’s acidity.
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Controlling Lead in Public Drinking Water Supplies
Among the rule’s initial requirements, LCR required
Related to proactive LSL replacement, America’s Water
owners or operators of water systems to survey the
Infrastructure Act (P.L. 115-270) amended SDWA Section
materials of its distribution system. This information
1452(a) to require public water systems to include—to the
enables systems to target tap-water monitoring at homes
extent practicable—the cost to replace LSLs in future
and other locations expected to be at high risk of lead
drinking water capital improvements needs surveys. SDWA
contamination. The LCR establishes an action level at 15
requires EPA to conduct the survey every four years, and
ppb for lead and 1,300 ppb for copper. If more than 10% of
EPA uses the results to determine the allotment among the
tap water samples exceed the rule’s action level, a
states for the annual grants for the Drinking Water State
community water system is not in violation of the rule, but
Revolving Fund (DWSRF) program. The inclusion of the
the water system is required to take actions, including
cost to replace LSLs in the survey may affect the allotments
optimizing corrosion control, public education, water
of DWSRF grants among the states.
quality parameter monitoring, source water treatment, and,
in some cases, LSL replacement. For more on the LCR, see
Implementation Challenges
CRS In Focus IF10446, Regulating Lead in Drinking
As communities identify options to address lead in water
Water: Issues and Developments.
supplies, LSL replacement is often identified as a way to
permanently remove a potential pathway of lead exposure
LSL Replacement
or as a way to minimize reliance on corrosion control
If a large community water system (50,000 or more
treatment. LSL replacement raises a number of
individuals) cannot limit lead in water through corrosion
implementation challenges for water systems and
control or other source water treatment, the LCR requires
communities. Among others, these challenges include the
the water system operator to replace LSLs. Typically, the
costs to replace these lines, which may result in partial LSL
water system owns the portion of line that extends from a
replacement (i.e., when the water system replaces some of
water main to a residence’s property line, a water meter, or
the LSL it owns and the remaining portion is not replaced).
shut-off valve between the main water line and the building,
while the remaining portion is owned by the property
The estimates of costs to replace LSLs vary widely (e.g.,
owner. The LCR requires community water systems that
$2,500-$5,500 per line, with some industry estimates at
exceed the action level to replace annually 7% of their
$8,700 per line). While disagreement may exist about LSL
LSLs, based on the rule’s initial materials’ evaluation, until
replacement costs, community water systems and individual
the action level is not exceeded for two consecutive six-
property owners are likely to face financial challenges to
month monitoring periods. In cases when the LSL
replace LSLs. In circumstances where the LSL is partially
scheduled for replacement extends past the property line,
owned by a property owner, under the current LCR, the
the LCR requires public water systems to offer the owners
public water system cannot compel the owner to replace the
with an opportunity to have their portion of the LSLs
owner’s portion of the LSL. Therefore, if the property
replaced, but the system is not required to pay for the
owner is unable or unwilling to pay for their portion of the
owners’ replacement costs for their portion of LSLs.
LSL replacement, lead may continue to leach into drinking
water from the remaining portion of the LSL.
Revisions to the Lead and Copper Rule
In 2004, EPA initiated a review of the LCR after increased
As noted, partial LSL replacement is allowed under the
lead levels were detected in the District of Columbia’s
LCR. Some studies have indicated that cutting into a LSL
drinking water after a water treatment change. This review
may disturb lead in the remaining portion resulting to
resulted in short-term revisions and clarifications that EPA
elevated lead levels for some period (e.g., days to weeks or
promulgated in 2007. These revisions require water systems
several months) after partial LSL replacement. EPA is
to notify the state agency if the system plans to change the
considering requiring full LSL replacement as a part of
source or treatment of its water supply. The requirements
LCR revisions. (For sources of federal funding for water
are intended to ensure that the state and system evaluate the
infrastructure projects, see CRS Report RL30478, Federally
potential impact such changes may have on corrosion
Supported Water Supply and Wastewater Treatment
control treatment.
Programs.)
EPA continues to work on comprehensive revisions to the
Lead in fixtures and interior plumbing can pose further
LCR. In 2015, EPA received recommendations for LCR
challenges to addressing lead in drinking water. Even with
revisions from the National Drinking Water Advisory
full LSL replacement, interior plumbing or fixtures in
Council (NDWAC). NDWAC recommendations specific to
private property may remain a potential source of lead
LSL replacement included requiring all water systems to
exposure. If water systems undertake proactive LSL
establish a proactive LSL replacement program, which
replacement, the issues of partial LSL replacement and of
would be costly and likely take decades to fully remove all
leaded interior plumbing or fixtures suggest that water
LSLs. As such, NDWAC recognized corrosion control’s
systems may need to maintain corrosion control treatment
importance and recommended that EPA revise the rule’s
to prevent lead from leaching into water. As a part of LCR
action level and requirements for corrosion control
revisions, EPA recognized the continued importance of
treatment and monitoring, among other revisions.
corrosion control treatment in reducing lead exposure and is
According to the Spring 2019 Unified Regulatory Agenda,
considering a range of options to strengthen corrosion
EPA plans to propose LCR revisions in 2019 and issue a
control requirements. EPA is also evaluating the LCR’s
final rule by July 2020.
action level and the monitoring, sampling, and public
notification requirements, along with other LCR changes.
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Controlling Lead in Public Drinking Water Supplies

IF11302
Elena H. Humphreys, Analyst in Environmental Policy


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