Updated March 12, 2024
Regulating PFAS Under the Clean Water Act
In recent decades, improvements in monitoring
industrial wastewater discharges. EPA has developed ELGs
technologies and analytical methods, combined with health
for 59 industrial source categories. For industrial facilities
research, have increased national attention to the presence
that discharge directly to regulated waters, EPA or states
of emerging contaminants in surface water. Detections of
incorporate the limits established in ELGs into the NPDES
one particular group of contaminants, per- and
permits they issue. For indirect dischargers—facilities that
polyfluoroalkyl substances (PFAS), have heightened public
discharge to publicly owned treatment works (POTWs)—
and congressional interest in the U.S. Environmental
pretreatment standards established in ELGs to prevent pass
Protection Agency’s (EPA’s) authorities under the Clean
through and interference at the POTW apply.
Water Act (CWA) to address PFAS in surface water.
The CWA also requires EPA to annually review all existing
Overview
ELGs and publish a biennial plan that includes a schedule
EPA has several CWA authorities it may use to address
for review and revision of promulgated ELGs, identifies
contaminants, such as PFAS, in surface water. Under the
categories of industrial sources discharging toxic or
CWA, a primary mechanism to control contaminants in
nonconventional pollutants that do not have ELGs, and
surface waters is through permits. The statute prohibits the
establishes a schedule for promulgating ELGs for any
discharge of pollutants from any point source (i.e., a
newly identified categories. EPA’s recent biennial plans
discrete conveyance) to waters of the United States without
and related actions have included efforts to identify and
a permit. The CWA authorizes EPA, and states with
characterize PFAS discharges, including the types and
delegated CWA permitting authority, to limit or prohibit
concentrations of PFAS discharged and the significant
discharges of pollutants in the National Pollutant Discharge
sources of PFAS discharges. The plans have also included
Elimination System (NPDES) permits they issue. These
details on the agency’s efforts to determine whether the
permits incorporate technology-based and water-quality-
agency should update ELGs for certain industrial source
based requirements.
categories to set effluent limitations for PFAS.
The CWA requires EPA to establish technology-based
In the 2021 Roadmap, EPA established timelines for action,
effluent (i.e., discharge) limits for industrial dischargers,
including data collection or rulemaking, on 11 industrial
known as Effluent Limitation Guidelines (ELGs). EPA is
categories. EPA targeted the end of 2024 as the deadline for
also required to issue water quality criteria for use in
“significant progress in its ELG regulatory work.” In
establishing water quality standards and water-quality-
January 2023, EPA released its latest biennial plan, which
based effluent limitations. The CWA also authorizes EPA
updated some of the agency’s plans and timelines for these
to utilize certain NPDES permit authorities to address
industrial categories. The 2023 Roadmap progress report
contaminants; to set pollutant limits and monitoring and
also included updated time frames. In these documents,
reporting requirements for contaminants in biosolids (i.e.,
EPA announced that the agency
sewage sludge from wastewater treatment facilities) if
• plans to publish proposed rules revising ELGs for the
sufficient scientific evidence shows there is potential harm
Organic Chemicals, Plastics, and Synthetic Fibers
to human health or the environment; and to designate
category by spring 2024 and the Metal Finishing and
contaminants as toxic or hazardous pollutants.
Electroplating Categories by the end of 2024;
• determined that revised ELGs for the Landfills Category
EPA announced projected timelines for several actions to
are warranted;
address PFAS using CWA authorities in its agency-wide
• will expand its study of the Textile Mills Category;
PFAS plan, the 2021 PFAS Strategic Roadmap. EPA has
• will initiate a new POTW Influent Study to collect
released annual progress reports on the 2021 Roadmap,
nationwide data on industrial discharges of PFAS to
most recently in December 2023, which included updates to
POTWs; and
the Roadmap’s time frames. To date, EPA has not
• will continue to monitor several other sectors to
published any final technology-based effluent limits or
determine whether additional steps are necessary.
water quality criteria to address any PFAS, nor has it
established requirements for PFAS in biosolids. In some
NPDES Authorities
instances, EPA has used NPDES permit authorities to
In cases where EPA has not established an ELG for a
address PFAS and has encouraged states to use such
particular industrial category or type of facility, or where
authorities. EPA has not designated any PFAS as a toxic
pollutants or processes were not considered when an ELG
pollutant or hazardous substance.
was developed, the permitting authority (EPA or states)
may still impose technology-based effluent limits on a case-
Effluent Limitation Guidelines
by-case basis. The permitting authority may also require
The CWA requires EPA to publish ELGs, which are the
facilities with NPDES permits to monitor for pollutants or
required minimum standards for specific pollutants in
conduct special studies as a means to collect data to support
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Regulating PFAS Under the Clean Water Act
future permit limits. The permitting authority may also
criteria for perfluorooctanoic acid (PFOA) and
include best management practices in permits on a case-by-
perfluorooctane sulfonate (PFOS). EPA targeted winter
case basis to carry out CWA provisions. However, the use
2022 as its deadline for publishing recommended aquatic
of some of these authorities can be limited when analytical
life criteria for PFOA and PFOS. EPA published draft
methods to detect specific pollutants are not available.
recommended aquatic life criteria for PFOA and PFOS for
public comment in May 2022, and intends to issue final
In the 2021 Roadmap, EPA discussed plans to leverage
criteria in the “near future” according to the 2023 Roadmap
some of these NPDES authorities. Central to these plans
progress report. EPA also intends to issue benchmarks for
was the September 2021 publication of a draft EPA-
PFAS that do not have sufficient data to define a
validated laboratory analytical method to test for 40 PFAS
recommended aquatic life criteria value.
compounds in eight different environmental media,
including surface water and wastewater. In the 2023
Biosolids Requirements
progress report for the 2021 Roadmap, EPA reported that it
Biosolids, also known as sewage sludge, are a product of
expects to finalize the method in the “coming months.” In
the wastewater treatment process. Biosolids may be applied
the interim, EPA recommends its use in NPDES permits.
to land for beneficial purposes (e.g., agriculture) or
disposed of through incineration or surface disposal. CWA
In line with the 2021 Roadmap, EPA has issued two
Section 405(d) requires EPA to establish numeric limits and
memoranda regarding PFAS and NPDES permits. EPA
management practices to protect public health and the
issued an EPA-specific memorandum in April 2022
environment from the reasonably anticipated adverse
detailing how the agency will address PFAS discharges in
effects of pollutants during the use or disposal of biosolids.
EPA-issued NPDES permits and for indirect dischargers
Section 405(d) also requires EPA to review its biosolids
where EPA is the pretreatment control authority. It
regulations at least every two years to identify additional
recommends that EPA permit writers include certain permit
toxic pollutants that may be present in biosolids and then
conditions for facilities where PFAS are expected or likely
promulgate regulations for those pollutants if sufficient
to be present in discharges. These conditions include
scientific evidence shows they may adversely affect public
effluent monitoring for the 40 PFAS detectable by EPA’s
health or the environment. EPA’s process to determine
draft analytical method and best management practices and
whether a pollutant may warrant regulation includes sewage
pollution prevention conditions (e.g., product elimination or
sludge surveys (i.e., surveys to identify the presence of
substitution when a reasonable alternative to PFAS is
pollutants in biosolids using samples taken from wastewater
available, minimizing accidental discharge through good
treatment plants), risk screening for pollutants found in
housekeeping practices, equipment decontamination, or
biosolids, and risk assessments for pollutants identified in
replacement). The memorandum also includes
biosolids that exceed a level of concern.
recommended permit conditions for POTWs where EPA is
the permitting authority and where EPA is the pretreatment
EPA has not established numeric limits or monitoring or
control authority, including effluent, influent, and biosolids
reporting requirements for PFAS in biosolids. In the 2021
monitoring requirements and best management and
Roadmap and 2023 Roadmap progress report, EPA says it
pollution prevention practices. It also states that EPA
will complete, by winter 2024, a risk assessment for PFOA
regions are expected to notify potentially affected
and PFOS in biosolids, which it will use to determine
downstream public water systems of draft permits with
whether to regulate these contaminants in biosolids.
PFAS-specific monitoring, best management practices, or
other conditions. In December 2022, EPA issued a
Toxic Pollutants or Hazardous Substances
companion memorandum to states providing guidance on
The CWA authorizes EPA to designate contaminants as
using similar NPDES authorities to reduce PFAS.
toxic pollutants (§307) or as hazardous substances (§311),
which may trigger other actions under the CWA and the
Water Quality Criteria
Comprehensive Environmental Response, Compensation,
CWA Section 304(a) requires EPA to develop and publish
and Liability Act. EPA has not designated any PFAS as
and “from time to time thereafter revise” criteria for water
toxic pollutants or hazardous substances under CWA
quality that accurately reflect the latest scientific
authorities and has not indicated that it plans to do so.
knowledge. Water quality criteria provide concentrations
for specific contaminants or conditions in a water body that,
Recent Congressional Action
if not exceeded, will protect particular designated uses of
PFAS-related issues have generated considerable
the water body (e.g., aquatic life, public drinking water
congressional interest in recent years. Recent Congresses
supply, recreation). These criteria are recommendations to
have held hearings and introduced and passed legislation to
states and tribal governments for use in developing their
address PFAS in surface water. The Infrastructure
own water quality standards, which they use to protect and
Investment and Jobs Act (P.L. 117-58) provided $1 billion
restore waters and to inform water-quality-based effluent
over five fiscal years to address emerging contaminants
limits in permits. EPA has developed several types of
(including PFAS) in wastewater through the Clean Water
criteria targeted to protect different designated uses, such as
State Revolving Fund. In the 118th Congress, Members
human health, aquatic life, and recreational criteria.
have introduced several bills related to PFAS in surface
water that have not passed either chamber.
In the 2021 Roadmap, EPA announced plans to develop
national recommended ambient water quality criteria for
Laura Gatz, Specialist in Environmental Policy
PFAS to protect human health and aquatic life. EPA
targeted the fall of 2024 for publishing human health
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Regulating PFAS Under the Clean Water Act


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https://crsreports.congress.gov | IF12148 · VERSION 2 · UPDATED

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