Regulating PFAS Under the Clean Water Act

Updated July 16, 2026

Regulating PFAS Under the Clean Water Act

In recent decades, improvements in analytical methods and

monitoring technologies, along with health research, have

increased national attention to the presence of emerging

contaminants in surface water. Detections of one particular

group of contaminants, per- and polyfluoroalkyl substances

(PFAS), have heightened public and congressional interest

in the U.S. Environmental Protection Agency’s (EPA’s)

authorities under the Clean Water Act (CWA) to address

PFAS in surface water.

Overview

EPA has several CWA authorities it may use to address

contaminants, such as PFAS, in surface water. A primary

mechanism in the CWA to control contaminants in surface

waters is through permits. The statute prohibits the

discharge of pollutants from any point source to waters of

the United States without a permit. The CWA authorizes

EPA and states with delegated CWA permitting authority to

limit or prohibit discharges of pollutants in their National

Pollutant Discharge Elimination System (NPDES) permits.

These permits incorporate technology-based and waterquality-based requirements.

The CWA requires EPA to establish technology-based

effluent (i.e., discharge) limits for industrial dischargers,

known as Effluent Limitation Guidelines (ELGs). EPA is

also required to issue water quality criteria for use in

establishing water quality standards for surface waters and

water-quality-based effluent limitations. The CWA also

authorizes EPA to utilize certain NPDES permit authorities

to address contaminants; to set pollutant limits and

monitoring and reporting requirements for contaminants in

biosolids (i.e., sewage sludge from wastewater treatment

facilities) if sufficient scientific evidence shows there is

potential harm to human health or the environment; and to

designate contaminants as toxic or hazardous pollutants.

In 2021, EPA first announced projected timelines for

several actions to address PFAS using CWA authorities in

its PFAS Strategic Roadmap. EPA released some annual

progress reports on the 2021 Roadmap. In February 2026,

EPA provided an update on its PFAS actions and referred to

ongoing CWA efforts. To date, EPA has not finalized any

ELGs to address any PFAS, has not set requirements for

PFAS in biosolids, and has not designated any PFAS as a

toxic pollutant or hazardous substance. EPA has published

water quality criteria for certain PFAS, and in some

instances has used NPDES permit authorities to address

PFAS and has encouraged states to use such authorities.

Effluent Limitation Guidelines

The CWA requires EPA to publish ELGs, which are the

required minimum standards for specific pollutants in

industrial wastewater discharges. EPA has developed ELGs

for 59 industrial source categories. For industrial facilities

that discharge directly to regulated waters, EPA or states

incorporate the limits established in ELGs into the NPDES

permits they issue. For indirect dischargers—facilities that

discharge to publicly owned treatment works (POTWs)—

pretreatment standards established in ELGs to prevent pass

through and interference at the POTW apply.

The CWA also requires EPA to annually review all existing

ELGs and publish a biennial plan that includes a schedule

for review and revision of promulgated ELGs, identifies

categories of industrial sources discharging toxic or

nonconventional pollutants that do not have ELGs, and

establishes a schedule for promulgating ELGs for any

newly identified categories. EPA’s recent ELG biennial

plans and related actions have included efforts to identify

and characterize PFAS discharges, including the types and

concentrations of PFAS discharged and the significant

sources of PFAS discharges. The plans have also included

details on the agency’s efforts to determine whether the

agency should update ELGs for certain industrial source

categories to set effluent limitations for PFAS.

In the 2021 Roadmap, EPA established timelines for action,

including data collection or rulemaking, on 11 industrial

categories. EPA targeted the end of 2024 as the deadline for

“significant progress in its ELG regulatory work.” EPA

released its latest preliminary ELG plan in December 2024,

updating some of the agency’s timelines. In these

documents, EPA indicated that the agency

• planned to publish proposed rules revising ELGs for the

Organic Chemicals, Plastics, and Synthetic Fibers

(OCPSF) Category (by fall 2024), the Metal Finishing

and Electroplating Categories (by spring 2026), and the

Landfills Category (in 2027);

• would continue its study of the Textile Mills Category;

• published a proposed information collection rule (in

2024) for a POTW Influent Study to collect nationwide

data on industrial discharges of PFAS to POTWs; and

• would continue to monitor several other sectors.

Since 2024, specific updates on EPA’s progress on its ELG

work and influent study have been limited. The 2026

Regulatory Agenda (posted July 3, 2026) includes new

timelines for a proposed OCPSF rule (July 2026) and a

proposed Metal Finishing rule (February 2027).

NPDES Authorities

In cases where EPA has not established an ELG for a

particular industrial category or type of facility, or where

pollutants or processes were not considered when an ELG

was developed, the permitting authority (EPA or states)

may still impose technology-based effluent limits on a caseby-case basis. The permitting authority may also require

facilities with NPDES permits to monitor pollutants or

conduct special studies to collect data to support future

permit limits. The permitting authority may also include

best management practices (BMPs) in permits on a case-by-

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Regulating PFAS Under the Clean Water Act

case basis. However, the use of some of these authorities

can be limited when analytical methods to detect specific

pollutants are not available.

In the 2021 Roadmap, EPA discussed plans to leverage

some of these NPDES authorities. Central to these plans

was the September 2021 publication of a draft EPA

analytical method (Method 1633A) to test for 40 PFAS

compounds in eight environmental media, including surface

water and wastewater. EPA finalized this method in

January 2024, along with a second method (Method 1621)

that can screen for thousands of known PFAS compounds

in water samples. In the 2024 Roadmap progress report,

EPA stated that it would propose the two methods for

adoption in regulations, “a necessary step for them to be

nationally required for CWA use.” EPA published a

proposed rule to adopt these methods in January 2025 (with

a final rule expected in July 2026). The 2026 Regulatory

Agenda also lists a rulemaking to update requirements for

some existing NPDES permit applications to address PFAS

monitoring and reporting. EPA anticipates a proposed rule

by January 2027 and a final rule by May 2027.

EPA also issued two memoranda regarding PFAS and

NPDES permits. The first (issued in April 2022) detailed

how the agency would address PFAS discharges in EPAissued NPDES permits and for indirect dischargers where

EPA is the pretreatment control authority. It recommended

that EPA permit writers include certain permit conditions

for industrial facilities where PFAS are expected or likely

to be present in discharges. These conditions include

effluent monitoring for the 40 PFAS detectable by EPA’s

draft Method 1633A and BMPs and pollution prevention

conditions. The memorandum also recommended permit

conditions for POTWs where EPA is the permitting

authority or the pretreatment control authority, including

effluent, influent, and biosolids monitoring requirements;

BMPs; and pollution prevention practices. In December

2022, EPA issued a second memorandum to states with

guidance on using similar NPDES authorities.

Water Quality Criteria

CWA Section 304(a) requires EPA to develop and publish

and “from time to time thereafter revise” criteria for water

quality that accurately reflect the latest scientific

knowledge. Water quality criteria provide concentrations

for specific contaminants or conditions in a water body that,

if not exceeded, will protect designated uses of the water

body (e.g., aquatic life, public drinking water supply,

recreation). These criteria are recommendations to states

and tribal governments for use in developing their own

water quality standards, which they use to protect and

restore waters and to inform water-quality-based effluent

limits in permits. EPA has developed several types of

criteria targeted to protect different designated uses, such as

human health, aquatic life, and recreational criteria.

In the 2021 Roadmap, EPA announced plans to develop

national ambient water quality criteria for PFAS to protect

human health and aquatic life. EPA targeted fall 2024 for

publishing human health criteria for perfluorooctanoic acid

(PFOA) and perfluorooctane sulfonate (PFOS). In

December 2024, EPA published for public comment draft

human health criteria for PFOA, PFOS, and

perfluorobutane sulfonic acid (PFBS). These criteria have

not been finalized. EPA targeted winter 2022 for publishing

aquatic life criteria for PFOA and PFOS. EPA published

final aquatic life criteria for PFOA and PFOS in October

2024. EPA issued benchmarks for eight PFAS that do not

have sufficient data to define an aquatic life criteria value.

Biosolids Requirements

Biosolids (i.e., sewage sludge) are a product of the

wastewater treatment process. Biosolids may be applied to

land for beneficial purposes (e.g., agriculture) or disposed

of through incineration or surface disposal. CWA Section

405(d) requires EPA to establish numeric limits and

management practices to protect public health and the

environment from the reasonably anticipated adverse

effects of pollutants during biosolid use or disposal. Section

405(d) also requires EPA to review its biosolids regulations

at least every two years to identify additional toxic

pollutants that may be present in biosolids and promulgate

regulations for those pollutants if sufficient scientific

evidence shows they may adversely affect public health or

the environment. EPA’s process to determine whether a

pollutant may warrant regulation includes sewage sludge

surveys (to identify the presence of pollutants in biosolids

using samples taken from wastewater treatment plants), risk

screening for pollutants found in biosolids, and risk

assessments for pollutants identified in biosolids that

exceed a level of concern.

EPA has not established numeric limits or monitoring or

reporting requirements for PFAS in biosolids. In the 2021

Roadmap, EPA said it would complete, by winter 2024, a

risk assessment for PFOA and PFOS in biosolids, which it

would use to determine whether to regulate them. In

January 2025, EPA published a draft risk assessment for

PFOA and PFOS in biosolids for public comment. In June

2026, EPA issued draft guidance for public comment. It did

not finalize the risk assessment. In the draft guidance

memorandum, EPA stated that the agency determined the

draft risk assessment had “a number of serious flaws.” EPA

opted to issue guidance to stakeholders to clarify potential

risks from PFOA and PFOS and recommend practices to

mitigate those risks when managing biosolids.

Toxic Pollutants or Hazardous Substances

The CWA authorizes EPA to designate contaminants as

toxic pollutants (§307) or as hazardous substances (§311),

which may trigger other actions under the CWA and the

Comprehensive Environmental Response, Compensation,

and Liability Act. EPA has not designated any PFAS as

toxic pollutants or hazardous substances under CWA

authorities and has not indicated that it plans to do so.

Recent Congressional Action

PFAS-related issues have generated congressional interest

in recent years. Recent Congresses have held hearings and

introduced and passed legislation to address PFAS. The

Infrastructure Investment and Jobs Act provided $1 billion

over five fiscal years to address emerging contaminants

(including PFAS) in wastewater through the Clean Water

State Revolving Fund. In the 119th Congress, Members

introduced several bills related to PFAS in surface water.

Laura Gatz, Specialist in Environmental Policy

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