Key Contacts
Federal PFAS Regulation and Litigation: Developments, Implementation, and What to Expect in the Second Year of the Trump Administration
Over the last two years, there has been a flurry of activity at the federal level related to the regulation of PFAS. In 2024, the Biden EPA finalized significant PFAS rulemakings under the Safe Drinking Water Act (SDWA) and Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), proposed regulations under the Resource Conservation and Recovery Act (RCRA), issued a significant guidance document on PFAS waste disposal and water quality criteria, and continued major PFAS data collection and disclosure efforts under the Clean Water Act (CWA), SDWA, Toxic Substance Control Act (TSCA), and Emergency Planning and Community Right-to-Know Act (EPCRA).
As the Trump Administration took office in 2025, major questions hung over the fate of these regulatory and data collection efforts. In many respects, the Trump Administration has moved forward with PFAS regulation, but with relaxed deadlines and reduced requirements.
As we move into 2026, the Trump Administration is poised to press forward with PFAS regulations under RCRA and the CWA, while modifying deadlines and regulations under the SDWA and TSCA. The Trump Administration will also be defending appeals of the PFAS maximum contaminant levels under the SDWA and the PFOA/PFOS hazardous substance designation under CERCLA with decisions in those cases possible by the end of 2026.
Set forth below is a more detailed summary of the regulatory developments from EPA under each of the following federal legislative programs and anticipated activities throughout 2026.
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
In April 2024, EPA under the Biden Administration finalized a rulemaking designating perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) (including their salts and structural isomers) as hazardous substances under CERCLA. The designation of PFOA and PFOS as hazardous substances under CERCLA has had an immediate impact on real estate transactions. Environmental professionals conducting an ASTM Phase I Environmental Site Assessment (for purpose of seeking landowner liability protections under CERCLA) must include PFOA and PFOS in the evaluation. Determining whether a release of PFOA and PFOS occurred in the past has proven difficult in some cases and has resulted in a wide range of conclusions by environmental professionals, which can complicate or delay transactions. The longer-term impacts are uncertain but potentially substantial. The wide-spread nature of PFOA and PFOS and the ultra-low remediation standards could greatly expand cleanup obligations at existing Superfund sites or add many new sites to the National Priorities List.
Shortly after EPA promulgated the final rule designating PFOA and PFOS as hazardous substances under CERCLA, several industry groups, led by the U.S. Chamber of Commerce, filed suit to challenge that decision in the D.C. Circuit. In February 2025, the D.C. Circuit granted a request by EPA to hold the case in abeyance pending the Trump Administration’s review of the hazardous substance designation. In September 2025, the Trump Administration announced that it intended to keep the hazardous substance designation for PFOA and PFAS and would defend the rule. The case was removed from abeyance and briefing resumed in November and December 2025. Oral argument is currently scheduled for January 20, 2026, with a decision possible later in the year.
Two other issues to watch in 2026 relate to the status of “passive receivers” of PFOA and PFOS and EPA’s plan to propose a framework for guiding future hazardous substance designations (the “Framework Rule”). First, with respect to “passive receivers,” EPA announced that it intended to work with Congress to amend CERCLA to provide “passive receivers” with statutory protection from liability for PFOA and PFOS. CERCLA’s retroactive and strict liability scheme can broadly apply to entities such as publicly owned wastewater treatment plants, farms, fire departments, or landfills that did not manufacture or generate PFOA or PFOS, but “passively received” PFOA and PFOS in raw materials, products, or wastes. Several members of Congress have raised concerns with EPA that local municipalities (and thus local ratepayers or taxpayers) may be on the hook for significant cleanup costs for any contamination from such passive receivers. EPA has previously issued guidance indicating that it would exercise enforcement discretion against certain passive receivers and focus instead on PFAS manufacturers or upstream users.
Second, with respect to the Framework Rule, EPA announced that the rule would provide a uniform approach to future hazardous substance designations, including how EPA would consider the costs of proposed designations. The Framework Rule will provide a process for EPA to potentially designate other PFAS compounds as hazardous substances under CERCLA.
Safe Drinking Water Act and Clean Water Act
PFAS MCL / National Primary Drinking Water Regulations
In May 2025, EPA announced that it intended to keep the maximum contaminant levels (MCLs) under the National Primary Drinking Water Regulations (NPDWR) for PFOA and PFOS but rescind the MCLs finalized by EPA during the Biden Administration in 2024 for four other PFAS compounds. In addition, EPA announced that it intended to extend the compliance deadline for the PFOA and PFOS MCLs from April 26, 2029, until April 26, 2031, and establish a “federal exemption framework” for certain water systems facing challenges such as economic hardship or lack of alternative water sources. According to EPA’s most recent Unified Agenda, EPA originally identified October 2025 as the target proposal date with a goal of finalizing the rule modifications by spring 2026. However, as of the publication date of this article, no proposed rule had been issued by EPA.
In deciding to keep the MCLs for PFOA and PFOS, the Trump EPA also committed to defending the rulemaking in a challenge brought by several industry groups before the D.C. Circuit. The case (American Water Works Association v. EPA, Case No. 24-1188) is currently being briefed with a decision possible in the second half of 2026.
Unregulated Contaminant Monitoring Rule (UCMR 5)
Starting in mid-2023 and continuing through early 2026, the EPA has been releasing the much-anticipated PFAS occurrence data for public drinking water systems through the UCMR 5. Officially ending in December 2025, the UCMR 5 required more than 10,000 public water systems (PWS) across the nation to monitor their systems for an expanded list of 29 individual PFAS compounds and report this information to EPA, and ultimately to the public. The release of UCMR 5 data, which has been published quarterly in “real-time,” along with a continuation of quarterly rolling data releases to the public, has generated great interest to-date and is anticipated to further drive regulatory actions and decision-making as referenced below.
Based on the most recent release of data (as of this publication), the EPA’s Data Summary: October 2025 indicates that the data released to date represent approximately 89 percent of the total PFAS occurrence results that the EPA expects to receive under the UCMR 5 effort. Based on the data that has been collected, EPA estimates that 7.8 percent of small PWSs (serving fewer than 3,300 people), 8.8 percent of small PWSs (serving 3,300 to 10,000 people), and 15.3 percent of large PWSs (serving more than 10,000 people) that have reported a full set of UCMR 5 results for at least one location had an average for one or more detection of PFAS that was greater than the respective MCL(s).
Additional data releases and finalization of the UCMR 5 data set is expected in early 2026.
Preliminary Regulatory Determination (RD 5) and CCL 5
As related to occurrence data collected during the UCMR 5 effort referenced above, EPA had completed a Preliminary Regulatory Determination decision (known as RD 5) for drinking water associated with its November 2022 Contaminant Candidate List 5 (CCL 5). The CCL 5 contained a list of contaminants that were then not subject to any proposed or promulgated National Public Drinking Water Regulation (NPDWR) but are known or anticipated to occur in public water systems. In a major development, the EPA’s publication of the CCL 5 included PFAS as a group, which according to EPA’s structural definition of PFAS, would have included over 10,000 individual chemical PFAS substances. On January 15, 2025, EPA published an Announcement of Preliminary Regulatory Determinations for Contaminants on the Fifth Drinking Water Contaminant Candidate List. Since EPA already made a determination to regulate six PFAS as referenced above, the Agency had decided not to regulate PFAS as a group under the NPDWR at this time. However, the EPA under the Biden Administration had originally cautioned that as data under the UCMR 5 were being collected concurrently with the RD 5 evaluation process, EPA intended to evaluate the full UCMR 5 dataset once it is available and would consider making regulatory determinations for the additional PFAS included contaminants in UCMR 5 in the future.
Per the Spring Unified Agenda, it is anticipated that a notice of proposed rulemaking will be published in early 2026 seeking to withdraw the regulatory determination for these PFAS and it appears unlikely that the current Trump Administration would seek to incorporate additional PFAS as part of any future Regulatory Determination actions.
Preliminary Effluent Guidelines (ELGs) Program Plan 16
Published on December 16, 2024, the EPA’s Preliminary Effluent Guidelines Program Plan 16 (Preliminary Plan 16) described analyses, studies, and rulemakings related to ELGs and pretreatment standards for PFAS. ELGs are national, technology-based regulations developed to control industrial wastewater discharges to surface waters and into publicly owned treatment works. ELGs are intended to represent the greatest pollutant reductions that are economically achievable for an industry. Notably, as part of the Preliminary Plan 16 (and previous Plan 15), EPA is seeking to revise the ELGs for the (1) Organic Chemicals, Plastics, and Synthetic Fibers (OCPSF) category to address PFAS wastewater discharges from facilities manufacturing PFAS, (2) revise the Metal Finishing ELGs to address PFAS discharges from chromium electroplating facilities, and (3) prepare revisions to the ELG applicable to landfills by collecting the data necessary to revise the ELG, which may include data collection from the industry and analysis of wastewater samples. EPA was also initiating a detailed study of PFAS processors to develop a more complete understanding of these facilities and their discharges to determine if revisions to the existing ELGs are appropriate.
Also, notable, and wide-reaching, EPA announced its intent to continue with a POTW Influent Study of PFAS, which will focus on collecting nationwide data on industrial discharges of PFAS to POTWs, including categories recently reviewed. EPA’s intention to undertake this study was to verify sources of PFAS in wastewater and help POTWs assess the need for control measures at the source. While the EPA sought to undertake the actions outlined in Preliminary Plan 16 and to continue with implementation of Plan 15, the commencement and pace of these activities depend on the agency’s Fiscal Year 2025 -2026 appropriations and operating plan.
With respect to regulatory developments, EPA’s most recent Unified Agenda lists both the ELGs for the OCPSF and Metal Finishing categories for notice of proposed rulemaking in January and July of 2026, respectively.
Test Methods and Methods Update Rule 22 (MUR 22)
Toward the end of the Biden Administration, the EPA issued a proposed rulemaking, known as the Methods Update Rule 22 (MUR 22). Under the proposed MUR 22, two important PFAS analytical methods are being sought for incorporation into the Code of Federal Regulations (C.F.R.). These include EPA Method 1633A (December 2024) which is a laboratory validated, direct injection EPA method for detection of 40 PFAS in wastewater, surface water, groundwater, soil, biosolids, sediment, landfill leachate, and fish tissue. Second, EPA Method 1621 (January 2024) is a single laboratory validated method to screen for organofluorines in wastewater. Method 1621 is labeled as a screening method because it does not quantify all organofluorines with the same accuracy and has some known interferences. The MUR 22 proposal seeks to formally codify the PFAS Method 1633A and Method 1621 as approved methods under 40 C.F.R Part 136.
According to the most recent Unified Agenda, the Trump Administration anticipates finalizing the MUR 22 rulemaking in early 2026. Approval of these methods through finalization of MUR 22 will support the much-anticipated Organic Chemicals, Plastics, and Synthetic Fibers (OCPSF) Effluent Limitations Guidelines and Standards (40 CFR Part 414) rulemaking to address PFAS discharges from facilities manufacturing PFAS.
Ambient Human Health Water Quality Criteria
Published in late December 2024, EPA’s Draft National Recommended Human Health Ambient Water Quality Criteria for PFOA, PFOS, and PFBS proposed stringent surface water quality criteria and national recommendations to states and Tribes authorized to establish their own water quality standards under the Clean Water Act. For example, the draft criterion for PFOA (water + organism) was established at an ultra-low threshold of 0.0009 ng/l (one ng/l equals one part per trillion). The EPA has received numerous comments on the draft criteria and will prepare a response to public comments document, update the draft criteria documents considering public comments, and consider new toxicity data prior to issuing final recommended criteria. Several commenters have suggested that, if finalized as drafted, the draft criteria would result in most waters of the nation being unable to meet the new criteria. Once finalized, states and authorized tribes can adopt the recommended criteria into water quality standards and establish numeric effluent limits for regulated facilities. It remains unclear at this time if the Trump Administration will prioritize finalizing the draft criteria in light of other PFAS-related regulatory priorities.
Biosolids Risk Assessment
As published in January 2025, EPA’s Draft Sewage Sludge Risk Assessment for Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonic Acid (PFOS) establishes that there may be human health risks exceeding acceptable thresholds for land application of sewage sludge containing 1 part per billion (ppb) of PFOA or PFOS. The draft risk assessment reflects EPA’s latest scientific understanding of the potential risks to human health and the environment posed by the presence of PFOA and PFOS in sewage sludge that is land applied as a soil conditioner or fertilizer (on agricultural, forested, and other lands), surface disposed (e.g., placed in a sewage sludge-only landfill called a monofill), or incinerated. EPA has received numerous comments on the draft risk assessment and may make changes prior to finalizing the guidance. While it remains unclear at this time if the Trump Administration will prioritize finalizing the draft risk assessment, it should be noted that the same toxicological underpinnings used to establish the MCLs under the National Primary Drinking Water Regulations were used in the draft biosolids risk assessment.
Clean Air Act (CAA)
EPA’s intent to regulate PFAS under the CAA was first referenced in the EPA’s PFAS Strategic Roadmap with a target date of Fall 2022. It remains unclear at this point, however, if the Trump Administration still intends to potentially regulate air emissions of PFAS, including listing certain PFAS as hazardous air pollutants (HAPs) under Section 112 of the CAA. Importantly, in 2024, three states submitted a petition to EPA requesting that the Agency designate certain PFAS as HAPs, but the petition does not appear to have garnered much attention from the current Administration.
In August 2023, EPA proposed a rulemaking for additional data collection from facilities that emit PFAS to the air through the Air Emissions Reporting Rule (AERR), which would seek to collect detailed PFAS data, enabling more refined air quality and exposure modeling. EPA was originally scheduled to finalize the rule in December 2024, however, EPA’s most recent Unified Agenda does not list this regulatory development as a near-term or long-term action.
EPA has also continued development and finalization of test methods to detect PFAS in stack emissions and ambient air. These methods include Other Test Method-50 (OTM-50) and work on a future Other Test Method-55 (OTM-55), which the EPA’s former Office of Research and Development (ORD) was developing for detection of PFAS products of incomplete combustion. It is unclear if the new iteration of ORD, known as the Office of Applied Science and Environmental Solutions, will pick up the test method development process and publish any new PFAS methods in 2026. OTMs are EPA test methods that have not yet gone through EPA’s rulemaking process but are needed to support agency initiatives. EPA was also previously considering development of sampling and analysis methods for targeted and non-targeted PFAS ambient air measurements. Applications would include fence-line monitoring for fugitive emissions, deposition, and receptor exposure using field deployable Time of Flight/Chemical Ionization Mass Spectrometer and summa canisters and sorbent traps techniques. However, with the recent restructuring and reductions in force at the EPA’s research division, it remains unclear what types of air monitoring research efforts will occur in 2026 and beyond.
Federal Guidance on PFAS Destruction
A third update of EPA’s Guidance on Destroying and Disposing of Certain PFAS and PFAS-Containing Materials That Are Not Consumer Products is anticipated to be released in early 2026. EPA’s Interim Guidance originally published in December 2020 (and subsequently updated in the Spring of 2024) outlined the then-current state of the science on techniques and treatments that may be used to destroy or dispose of PFAS and PFAS-containing materials from non-consumer products, including Aqueous Film Forming Foam, soil and biosolids, textiles, spent filters, membranes, resins, granular carbon, and other waste from water treatment, landfill leachate containing PFAS, and solid, liquid, or gas waste streams containing PFAS from facilities manufacturing or using PFAS. The guidance does not apply to consumer products, such as non-stick cookware and water-resistant clothing. The guidance generally describes thermal treatment, landfill, and underground injection technologies that may be effective in the destruction or disposal of PFAS and PFAS-containing materials. As announced by the Trump Administration in April 2025, EPA plans to update this important guidance on an annual basis moving forward, based on the evolution of PFAS treatment techniques, research and development, and analytical techniques to measure PFAS.
Resource Conservation and Recovery Act (RCRA)
As outlined in our article from March 2024, EPA published two proposed rules that would allow EPA to regulate certain PFAS and other emerging chemicals of concern under RCRA. Specifically, these rulemakings, if adopted, would make these substances subject to investigation and cleanup requirements at permitted hazardous waste facilities. Perhaps more significantly, one of the proposals would put the foundation in place for future designation of waste containing particular PFAS as listed hazardous wastes. The proposed rulemaking would add PFOA, PFOS, PFBS, and GenX to the RCRA Hazardous Constituents list under Appendix VIII.
According to EPA’s most recent Unified Agenda, the Trump EPA intends to finalize the proposed rule by April 2026.
Emergency Planning and Community Right-to-Know Act (EPCRA)
A proposed rule to strengthen and potentially significantly expand PFAS reporting required under the Toxic Release Inventory (TRI) was published in October 2024. EPA’s proposed rule sought to add 16 individual PFAS and 15 PFAS categories to the TRI and designate them as chemicals of special concern. EPA also proposed to reclassify some PFAS previously added to the TRI individually as part of a PFAS category and clarify how PFAS are automatically added to the TRI under the National Defense Authorization Act (NDAA). EPA is evaluating comments received on the proposed rule and will consider how to address PFAS compound categories and what events may trigger the automatic addition of a PFAS to the TRI. Pursuant to the most recent Unified Agenda, EPA intends to publish as a final rulemaking in early 2026.
Another proposed TRI rulemaking was published in January 2025, which clarifies when companies must notify a customer that one of their mixtures or trade name products contains a PFAS listed on the TRI in accordance with Section 7321(c) of the Fiscal Year 2020 National Defense Authorization Act. Pursuant to the most recent Unified Agenda, EPA intends to publish as a final rulemaking in late 2026.
Finally, for Reporting Year 2025 (reporting forms due by July 1, 2026), the NDAA automatically added nine additional PFAS to the TRI list (for a total of 205 chemicals). The addition of these nine PFAS was finalized in a January 2025 rulemaking. Facilities in TRI-covered industry sectors should have begun tracking and collecting data on these chemicals during 2025.
Toxics Substances Control Act (TSCA) Section 8(a)(7) Reporting
In a major development from November 2025, the Trump Administration published proposed deregulatory amendments to the TSCA Section 8(a)(7) implementing regulations for reporting and recordkeeping requirements for PFAS. The amendments address proposed deregulatory elements to the EPA’s final rule from October 2023 which requires manufacturers (including importers) of PFAS in any year between 2011–2022 to report certain data to EPA related to exposure and environmental and health effects. Under TSCA Section 8(a)(7), which was added as part of the National Defense Authorization Act for fiscal year 2020, any person who has manufactured for commercial purposes certain PFAS substances at any period from January 1, 2011 through December 31, 2022 must report specific information to EPA, including, among other things, chemical identity, use information, manufactured amounts, environmental and health effect data, and worker exposure data. The original rulemaking was to result in the publication of the largest-ever dataset of PFAS manufactured (including imported) in the United States. Whether a PFAS substance is subject to reporting is determined using a structural definition, which EPA estimates the number of PFAS that are subject to the reporting rule are over 1,400 unique substances. Under the original rule, “Manufacturers” include importers of both PFAS chemical substances and articles that contain PFAS. Like other TSCA reporting rules, such as the Chemical Data Reporting (CDR) Rule, manufacturers are required to report information “to the extent known or reasonably ascertainable by” the manufacturer. However, unlike CDR, there are no de minimis thresholds or exemptions for unintentional impurities or byproducts for the Section 8(a)(7) rule. Accordingly, the original Section 8(a)(7) rule imposed some level of diligence that could include inquiries outside the organization to “fill gaps in the submitter’s knowledge.” Persons who have only processed, distributed in commerce, used and/or disposed of PFAS, however, are not subject to the final rule. The deadline for PFAS manufacturers to submit the required information has been extended multiple times, now to October 13, 2026 (entities that qualify as “small manufacturers” are granted an extra six months). For additional detail, please review our article covering EPA’s proposed changes to TSCA Section 8(a)(7).
