Updated May 26, 2022
Regulating Drinking Water Contaminants: EPA PFAS Actions
The detection of certain per- and polyfluoroalkyl substances
and others address contaminants that lack federal (or state)
(PFAS) in some public water supplies has generated public
drinking water standards. In 2016, EPA issued Lifetime
concern and increased attention to the U.S. Environmental
Health Advisory levels for PFOA and PFOS in drinking
Protection Agency’s (EPA’s) actions to respond to PFAS
water at 70 parts per trillion (ppt) separately or combined.
using Safe Drinking Water Act (SDWA) authorities. For
EPA developed these advisory levels to protect the most
more than a decade, EPA has been evaluating PFAS under
sensitive population groups, with a margin of protection,
SDWA to determine whether a national drinking water
over a lifetime of daily exposure.
regulation is warranted for one or more of these substances.
In March 2021, EPA finalized determinations to develop
Regulating Contaminants Under SDWA
SDWA regulations for the two most frequently detected
SDWA authorizes EPA to regulate contaminants in water
PFAS, perfluorooctanoic acid (PFOA) and perfluorooctane
provided by public water systems and specifies a multistep
sulfonate (PFOS) (86 Federal Register 12272). EPA’s
process for evaluating contaminants to determine whether a
determination triggers a SDWA requirement to propose a
drinking water regulation is warranted (42 U.S.C. §300g-1).
regulation within 24 months (e.g., by March 2023 for
As discussed below, the process includes identifying
PFOA and PFOS), and finalize the rule within 18 months of
contaminants of potential concern, assessing health risks,
the proposal. In EPA’s October 2021 PFAS Strategic
collecting occurrence data (and developing any necessary
Roadmap, the agency states that it intends to propose a
test methods), and making determinations as to whether a
PFOA and PFOS drinking water regulation by fall 2022,
federal drinking water regulation is warranted.
and finalize the rule by fall 2023.
Identifying Contaminants for Evaluation
In addition, the 116th Congress enacted legislation directing
Every five years, EPA is required to publish a list of
EPA to increase PFAS monitoring in water supplies, and
contaminants that are known or anticipated to occur in
authorizing appropriations for grants to address PFAS in
public water systems and may warrant regulation under the
public water supplies, among other provisions. The 117th
act (42 U.S.C. §300g-1(b)). In 2009, EPA placed PFOA and
Congress provided appropriations for such grants.
PFOS on the third such contaminant candidate list (CCL 3)
for evaluation (74 Federal Register 51850). In November
Background
2016, EPA issued CCL 4, which carried over many CCL 3
PFAS include thousands of diverse chemicals, some of
contaminants, including PFOA and PFOS, for further
which have been used for decades. The chemical
evaluation (81 Federal Register 81103).
characteristics of PFAS led to their use in an array of
industrial, commercial, and U.S. military applications.
Monitoring for Unregulated Contaminants
These include use in fighting fuel-based fires and the
To generate nationwide occurrence data for unregulated
processing and manufacturing of numerous products (e.g.,
contaminants, SDWA directs EPA to promulgate, every
stain-resistant and waterproof fabrics, nonstick cookware,
five years, an unregulated contaminant monitoring rule
and food containers). PFOA and PFOS were the most
(UCMR) that requires water systems operators to test for up
produced PFAS, historically. EPA worked with U.S.
to 30 contaminants (42 U.S.C. §300j-4). EPA generally
manufacturers as they voluntarily phased out production of
requires monitoring by operators of all public water systems
PFOS, PFOA, and related substances.
that serve more than 10,000 persons, plus a representative
sample of smaller systems. (More than 80% of U.S.
In 2016, EPA reported that PFOA and/or PFOS were
residents receive water from public water systems that serve
detected in at least one public water system in 24 states.
more than 10,000 individuals. More than half of water
Four other PFAS were also detected in some systems.
systems serve fewer than 500 people.)
SDWA provides EPA with several authorities to address
contaminants in drinking water supplies and sources. These
In 2012, EPA issued the UCMR 3, requiring roughly 5,000
include the authority to issue health advisories, regulate
water systems to monitor for six PFAS—including PFOA
contaminants in public water supplies, and issue
and PFOS—between January 2013 and December 2015.
“emergency powers” orders in certain circumstances.
According to EPA, 63 water systems (1.3%) serving an
estimated 5.5 million individuals detected PFOA and/or
Drinking Water Health Advisories
PFOS at levels above EPA’s lifetime health advisory level
SDWA authorizes EPA to issue health advisories for
of 70 ppt (separately or combined). UCMR 4 did not
contaminants (42 U.S.C. §300g-1(b)(1)(F)). Advisories
require monitoring for PFAS.
provide information on health effects, testing methods, and
treatment techniques for contaminants of concern. They
As directed by the National Defense Authorization Act for
also include nonenforceable levels to help water suppliers
FY2020 (2020 NDAA; P.L. 116-92), EPA included on the
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Regulating Drinking Water Contaminants: EPA PFAS Actions
next UCMR (i.e., UCMR 5) every PFAS for which EPA
as is “feasible” using best available technology or other
had identified a validated test method. (EPA has validated
means available, taking costs into consideration. SDWA
test methods for 29 PFAS.) In December 2021, EPA
requires that regulations include analytical methods and
finalized UCMR 5, which requires all water systems
feasible treatment methods that public water systems can
serving 3,300 or more people to monitor for 29 PFAS
use to monitor for contaminants and comply with the MCL.
(including the 6 PFAS identified in UCMR 3) and a metal
They also include monitoring and reporting requirements
(i.e., lithium) between 2023 and 2025, and report the data
(42 U.S.C. §300f(1), §300g-1).
by 2026 (86 Federal Register 73131). As amended by
Drinking Water Regulation Enforcement
America’s Water Infrastructure Act of 2018 (P.L. 115-270),
Drinking water regulation enforcement is generally a state
SDWA requires EPA to pay the reasonable costs of testing
responsibility. SDWA requires EPA to delegate
and laboratory analysis for systems serving between 3,300
enforcement authority for SDWA regulations to states that
and 10,000 individuals (42 U.S.C. §300j-4(j)). Accordingly,
meet certain criteria (42 U.S.C. §300g-2). Currently, 49
EPA stated in its rule that the inclusion of such systems in
states, the territories, and the Navajo Nation have applied
UCMR 5 is dependent on appropriations. For FY2023, EPA
for and received primacy for the drinking water program.
requests $12 million to support such monitoring.
EPA retains enforcement authority for Wyoming, the
Regulatory Determinations
District of Columbia, and other Indian tribes.
SDWA requires EPA to make a regulatory determination of
Emergency Powers
whether or not to promulgate a national drinking water
SDWA authorizes EPA to take actions it deems necessary
regulation for at least five contaminants every five years. In
to abate an imminent and substantial endangerment to
selecting contaminants for regulatory determinations (RDs),
public health from a contaminant (regulated or unregulated)
SDWA directs EPA to prioritize those that present the
that is present in or likely to enter a public water system or
greatest health concern while considering a contaminant’s
an underground source of drinking water (42 U.S.C. §300i).
effects on subgroups that may be at greater risk of adverse
This authority is available if state and local authorities have
health impacts from exposure (e.g., infants, pregnant
not acted. EPA may issue orders to require persons who
women).
caused or contributed to the endangerment to provide
alternative water supplies or to treat contamination. Since
To make a positive RD, SDWA directs EPA to find the
2002, EPA has used this authority to require responses to
following: (1) a contaminant may have an adverse health
PFOA and/or PFOS contamination of water supplies
effect; (2) it is known to occur or there is a substantial
associated with four sites, including three Department of
likelihood that it will occur in water systems at a frequency
Defense (DOD) sites.
and at levels of public health concern; and (3) in the sole
judgment of the EPA Administrator, regulation of a
MCLs and Remedial Actions
contaminant presents a meaningful opportunity for reducing
Under the Comprehensive Environmental Response,
health risks. EPA finalized positive RDs for PFOA and
Compensation, and Liability Act (CERCLA, or “Superfund”),
PFOS in March 2021 (86 Federal Register 12272). Since
MCLs may be considered in selecting remedial actions for
1996, EPA has finalized positive RDs for three
releases of hazardous substances, pol utants, and other
contaminants (i.e., PFOA, PFOS, and perchlorate). (In
contaminants (42 U.S.C. §9621(d)). CERCLA establishes
2020, EPA withdrew the positive RD for perchlorate [85
liability only for releases of hazardous substances. No PFAS
Federal Register 43990.])
has been designated as a hazardous substance, though the
PFAS Strategic Roadmap states that EPA plans to propose to
Developing Drinking Water Regulations
designate PFOA and PFOS as hazardous substances in spring
Once EPA makes a final determination to regulate a
2022, and finalize by summer 2023. (See CRS Report R45986,
substance, SDWA prescribes a schedule for promulgating
Federal Role in Responding to Potential Risks of Per- and
regulations. EPA is required to propose a rule within 24
Polyfluoroalkyl Substances (PFAS) for more information.)
months and promulgate a final drinking water regulation
within 18 months after the proposal. EPA may extend the
Recent Congressional Action
deadline to publish a final rule for up to nine months (42
Numerous bills have been introduced in recent Congresses
U.S.C. §300g-1(b)(1)). Regulations generally take effect
to address PFAS in drinking water, and some have been
three years after promulgation. EPA may allow up to two
enacted. The Infrastructure Investment and Jobs Act (IIJA;
additional years if the Administrator determines that water
P.L. 117-58) Division J, Title VI appropriates $4 billion
system capital improvements are needed. States have the
over FY2022-FY2026 to address emerging contaminants
same authority to allow two additional years on a system-
with a focus on PFAS in drinking water through a grant
by-system basis (42 U.S.C. §300g-1(b)(10)).
program within the Drinking Water State Revolving Fund
added by the 2020 NDAA. IIJA also appropriates $5 billion
For each regulation, EPA is required to establish a
over FY2022-FY2026 for a SDWA grant program to
nonenforceable maximum contaminant level goal (MCLG)
address emerging contaminants in small and disadvantaged
at a level at which no known or anticipated adverse health
communities. See CRS Report R45793, PFAS and Drinking
effects occur, with an adequate margin of safety. For each
Water: Selected EPA and Congressional Actions for more
contaminant covered by the regulation, EPA generally
information on EPA actions and recent bills.
specifies a maximum contaminant level (MCL)—an
enforceable standard applicable to public water suppliers.
Elena H. Humphreys, Analyst in Environmental Policy
SDWA directs EPA to set the MCL as close to the MCLG
IF11219
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Regulating Drinking Water Contaminants: EPA PFAS Actions


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https://crsreports.congress.gov | IF11219 · VERSION 10 · UPDATED

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