On May 18, 2026, the U.S. Environmental Protection Agency (“EPA”) issued two proposed rules designed to modify the 2024 national drinking water standards and compliance schedule promulgated for per- and polyfluoroalkyl substances (“PFAS”) (the “2024 PFAS Rule”). PFAS are a group of thousands of human-made chemical compounds widely used for decades in products and processes that, current scientific research indicates, contribute to adverse health outcomes, including increased risk of some cancers. Consuming public drinking water is one way in which Americans may be exposed to PFAS in their daily lives.

The 2024 PFAS Rule, which Kaplan Kirsch detailed here, required public drinking water providers nationwide to monitor public drinking water supplies for six PFAS compounds. Detections above the maximum contaminant levels (“MCLs”) would trigger the need to treat drinking water supplies to meet the MCLs. The 2024 PFAS Rule established MCLs of 4 parts per trillion (“ppt”) for PFOA and PFOS, individually; 10 ppt for PFNA, PFHxS, and PFPO-DA (commonly known as “GenX”); and a Hazard Index MCL of 1 for mixtures of PFHxS, PFNA, HFPO-DA, and PFBS. The 2024 PFAS Rule required public drinking water providers to comply with the new MCLs by 2029.

In a May 16, 2026 press release, which Kaplan Kirsch detailed here, EPA stated its intent to issue a new PFAS rule that would limit the 2024 PFAS Rule in important respects. EPA stated it would reduce the scope of PFAS addressed to only the two most prevalent PFAS compounds, PFOA and PFOS, because the agency determined the MCL decisions for the other PFAS compounds had not followed the legal process laid out in the Safe Drinking Water Act (“SDWA”). EPA also stated its intent to extend the compliance timeline by two years, from 2029 to 2031, because some public drinking water systems, especially small or disadvantaged ones or those located in remote or rural areas, needed more time to achieve compliance with the new PFOA and PFOS MCLs. 

Now, EPA has issued two new proposed PFAS rules to limit the 2024 PFAS Rule. These proposed rules largely follow the framework laid out in EPA’s 2025 press release. 

The “Proposed PFAS Rescission Rule” would limit regulation to PFOA and PFOS, just as EPA indicated in 2025, “rescinding” the MCLs for PFHxS, PFNA, and HFPO-DA and the Hazard Index MCL that EPA issued in the 2024 PFAS Rule. The proposed rule states that EPA should not have proposed and finalized regulatory determinations and regulations for those PFAS compounds “simultaneously and in tandem” because such action is “not authorized . . . under the best reading of the [SDWA]”.

The “Proposed PFOA and PFOS Compliance Extension Rule” would modify the implementation schedule from the 2024 PFAS Rule to allow public water supplies the option to request up to two additional years (until 2031) to meet the MCLs for PFOA and PFOS. EPA decided against an automatic extension so as not to slow down public water systems that are on track to meet the original 2029 compliance deadline. The agency believes the “opt in” structure of the extension will allow public water systems facing legitimate implementation hurdles more time to address challenges and meet the standards with EPA’s approval, oversight, and assistance. EPA specifically seeks public input on certain aspects of the proposed rule, including the agency’s legal justification for extension of compliance deadlines, what criteria the agency should use when reviewing extension requests, whether the risk to human health from exposure to PFOA and PFOS from water systems that receive extensions is unreasonable, and more. See Section V.A. of proposed rule for full list.

In addition to the two proposed rules, EPA announced nearly $1 billion in new grant funding to states to address PFAS and other emerging contaminants in drinking water through the Emerging Contaminants in Small or Disadvantaged Communities Grant. With this new funding, EPA has made $5 billion available through this program over the last five years. EPA states it will act quickly to make the new funding available to communities that need it to identify PFAS contamination and treat drinking water to meet the PFOA and PFOS MCLs.

Prepublication versions of the proposed rules are available here (for the Proposed PFAS Rescission Rule) and here (for the Proposed PFOA and PFOS Compliance Extension Rule). Once the rules are published in the Federal Register, EPA will accept written comments in the public docket for 60 days. EPA will also hold a virtual public hearing on July 7, 2026, when members of the public who register for the hearing may provide verbal comments on the proposed rule. Information regarding registration for the hearing is available here.

For more information about PFAS, or how PFAS regulations or liability may impact your organization, please contact Thomas A. Bloomfield, Polly B. Jessen, or Sara V. Mogharabi.