Updated June 1, 2021
Controlling Lead in Public Drinking Water Supplies
Communities may face a range of issues associated with
and establish a program to remove lead-lined drinking
aging water infrastructure, including elevated lead levels in
water coolers (SDWA Part F).
tap water. Because of lead’s toxicity, even at low levels,
reducing lead exposures from drinking water and other
Limiting Lead in Plumbing Materials
sources remains a public health priority. Other sources of
In 1986, Congress amended SDWA to prohibit the use of
lead exposure include lead-based paint and contaminated
plumbing (e.g., pipes or pipe fittings) that were not “lead-
soil and dust from deteriorated lead-based paint. Nationally,
free,” which was defined at the time as solder and flux with
the phaseouts of leaded gasoline and lead-based paint,
no more than 0.2% lead and pipes with no more than 8%
along with regulatory controls and technical changes, have
lead (P.L. 99-339). Congress authorized states to enforce
reduced lead exposures. Since the late 1970s, overall blood
these provisions and authorized EPA to withhold a portion
lead levels in children (ages one to five) have declined an
of grant funds from a state for failure to enforce.
estimated 94%.
Congress expanded the lead prohibition to include fixtures
Sources of Lead in Drinking Water
in 1996 (P.L. 104-182) and reduced the allowable lead
Most contaminants, when found in public water supplies,
content in “lead-free” plumbing materials in 2011 (P.L.
are detected and treated at the water treatment facility. In
111-380). Lead-free is now defined as no more than 0.25%
contrast, lead occurs in tap water after treated water enters
lead across wetted surfaces of plumbing materials. Many
the distribution system, where water is corrosive and lead
communities and homes may still have pipes and plumbing
can leach from pipes, plumbing materials, and fixtures (e.g.,
that contains more lead than is allowed for newer materials.
faucets). Corrosion is a chemical reaction between the
EPA’s Lead and Copper Rule (1991-Present)
water and the plumbing materials. Factors affecting
SDWA authorizes states to assume primary responsibility
corrosion include the water’s acidity, temperature, water
for oversight and enforcement of public water system
use patterns, and the presence or absence of protective
compliance with drinking water regulations. EPA, among
coatings of mineral deposits that can accumulate inside
other responsibilities, retains oversight authority over state
pipes, among others. Accordingly, controlling corrosion has
programs. Public water systems can be owned and operated
been the principal method used to keep lead in tap water.
by private or public entities, including municipalities or
The presence of leaded pipes and materials in community
local governments.
water systems (CWSs) and homes generally depends on the
In 1991, EPA issued the Lead and Copper Rule (LCR),
age of the water system and residences. Before the 1930s,
which replaced a standard for lead in drinking water of 50
lead pipes were commonly used to extend water service
parts per billion (ppb) measured at the treatment plant.
from the water main under the street to a residence or other
Because lead or copper generally enters the water after it
building inlet. These lead pipes are known as lead service
leaves the plant, the rule required an initial survey of the
lines (LSLs). Nationwide LSL estimates vary. A 2016
materials that comprised a water system’s distribution
analysis estimated that the number of LSLs nationwide
systems. This information enabled systems to target tap-
declined from approximately 10 million to 6 million over
water monitoring at homes and other locations expected to
three decades. EPA estimates that the current number of
be at high risk of lead contamination. The LCR established
LSLs may range from 6.3 million to 9.3 million. Leaded
action levels at 15 ppb for lead and 1,300 ppb for copper. If
plumbing materials (e.g., brass fixtures and copper pipes
more than 10% of tap water samples exceed the rule’s
with lead solder) in buildings, such as child care facilities
action level, a CWS is not in violation of the rule, but the
and residences, can also contribute to lead in drinking
water system is required to take treatment technique
water.
actions, including optimizing corrosion control; public
Safe Drinking Water Act
education; water quality parameter monitoring; source
water treatment; and, in some cases, LSL replacement.
The Safe Drinking Water Act (SDWA) authorizes the U.S.
Environmental Protection Agency (EPA) to regulate the
Under the rule, public water systems are required to
quality of water delivered by public water systems (42
optimize and maintain treatment for corrosion control.
U.S.C. §§300f et seq.). Under SDWA, Congress has
Usually, corrosion control treatment involves adjusting the
addressed exposure to lead in drinking water using several
water’s acidity to mitigate the treated water’s potential to
approaches, including (1) limiting lead in plumbing
leach lead from the distribution system or interior
materials and fixtures (SDWA §1417) and (2) authorizing
plumbing. Such treatment can provide a cost-effective way
EPA to regulate contaminants, such as lead, in public water
to control lead in drinking water, but maintaining control of
systems through national primary drinking water
corrosion is complex, and requires consideration of factors
regulations (SDWA §1412). Further, Congress amended
such as source water quality and composition of distribution
SDWA to address lead in child care programs and schools
system and plumbing in individual homes and other
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Controlling Lead in Public Drinking Water Supplies
properties. Further, actions to comply with other SDWA
exceeded for four consecutive six-month monitoring
drinking water regulations may increase the water’s acidity.
periods. Unlike the LCR, the LCRR would not allow water
systems to “test out” of the 3% replacement requirement
In 2004, EPA began reviewing the LCR after increased lead
levels were detected in the District of Columbia’s drinking
using tap sample results below the action level for two
consecutive six-month monitoring periods. Partial LSL
water after a water treatment change. This review resulted
replacement would not count toward the 3% replacement
in short-term revisions and clarifications that EPA issued in
rate or replacement goal. The LCRR would require a water
2007. The revisions require water systems to notify the state
system replace its portion of an LSL within 45 days (or 180
agency (or EPA) if the system plans to change the source or
days with state notification) of being notified of a
treatment of its water supply. The requirements are
customer’s intent to replace their LSL portion.
intended to ensure that the state and system evaluate the
potential impact such changes may have on corrosion
Implementation Challenges
control treatment.
As communities identify options to address lead in water
Lead and Copper Rule Revisions
supplies, LSL replacement is often identified as a way to
permanently remove a potential pathway of lead exposure
In 2015, EPA received recommendations for LCR revisions
or as a way to minimize reliance on corrosion control
from the National Drinking Water Advisory Council
treatment. LSL replacement raises a number of
(NDWAC). NDWAC recommendations included requiring
implementation challenges for water systems and
all water systems to establish a proactive LSL replacement
communities. Among others, these challenges include the
program, noting that it would be costly and likely take
costs to replace these lines, which may result in partial LSL
decades to fully remove all LSLs. As such, NDWAC
recognized corrosion control’s importance and
replacement (i.e., when the water system replaces the LSL
recommended that EPA revise the rule’s action level and
portion that it owns and the owner’s remaining portion is
not replaced).
requirements for corrosion control treatment and
monitoring, among other revisions.
The costs to replace LSLs can vary widely across localities.
According to EPA, the cost of LSL replacement ranges
EPA published final Lead and Copper Rule Revisions, or
from $1,200 to $12,300 per line. CWSs and individual
LCRR, in the Federal Register on January 15, 2021, with
homeowners may face financial challenges to replace LSLs.
an effective date of March 16, 2021, which was extended
In circumstances where the LSL is partially owned by a
until June 17, 2021. EPA also proposed to delay the rule’s
property owner, under the LCRR, the public water system
effective date to December 16, 2021. The LCRR revises the
cannot compel the owner to replace the owner’s portion of
1991 LCR, and retains for certain purposes the 1991 LCR’s
the LSL. Therefore, if the property owners are unable or
15 ppb lead action level. Among other changes, the LCRR
unwilling to pay for their portion of the LSL replacement,
also establishes a new lead trigger level at 10 ppb, based on
lead may continue to leach into drinking water from the
the 90th percentile of tap water samples. (CRS Report
remaining portions of the LSL. (For sources of federal
R46794, Addressing Lead in Drinking Water: The Lead and
funding for water infrastructure projects, see CRS Report
Copper Rule Revisions (LCRR), discusses the LCRR.)
R46471, Federally Supported Projects and Programs for
Wastewater, Drinking Water, and Water Supply
LSLs and LSL Replacement Requirements
Infrastructure.)
Typically, the water system owns the portion of service line
that extends from a water main to a residence’s property
Related to proactive LSL replacement, America’s Water
line, a water meter, or a shut-off valve between the main
Infrastructure Act of 2018 (P.L. 115-270) amended SDWA
water line and the building, while the remaining portion is
Section 1452(a) to require public water systems to
owned by the property owner. Under the 1991 LCR, CWSs
include—to the extent practicable—the cost to replace
that have optimized corrosion control and still exceed the
LSLs in future drinking water capital improvements needs
lead action level are required to replace at least 7% of their
surveys. SDWA requires EPA to conduct the survey every
LSLs annually until the action level is not exceeded for two
four years, and EPA uses the results to determine the
consecutive six-month monitoring periods. In cases when
allotment among the states for the annual grants for the
the LSL scheduled for replacement extends past the
Drinking Water State Revolving Fund (DWSRF) program.
property line, the 1991 LCR requires public water systems
The inclusion of the cost to replace LSLs in the survey may
to offer the owners an opportunity to have their portion of
affect state allotments of DWSRF capitalization grants.
the LSL replaced, but the system is not required to pay for
Lead in household plumbing can pose further challenges to
the owners’ replacement costs for their portions of LSLs.
addressing lead in drinking water. Even with full LSL
Under the LCRR, water systems would be required to
replacement, interior plumbing or fixtures in buildings may
develop an inventory of LSLs (or demonstrate their
remain a source of lead exposure. If systems undertake
absence) within three years of promulgation of the final
proactive LSL replacement, the issues of partial LSL
rule. The LCRR would require water systems with LSLs or
replacement and of leaded interior plumbing or fixtures
service lines of unknown material to periodically update
suggest that water systems may need to maintain corrosion
their inventory. CWSs with LSLs would have three years to
control treatment to prevent lead in tap water.
develop a plan to replace all LSLs in their system. Under
the LCRR, if a water system serving more than 10,000
Elena H. Humphreys, Analyst in Environmental Policy
persons exceeded the action level, the system would be
IF11302
required to replace 3% of the LSLs annually based on a
two-year rolling average until the action level was not
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Controlling Lead in Public Drinking Water Supplies
Disclaimer
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https://crsreports.congress.gov | IF11302 · VERSION 4 · UPDATED