May 20, 2026
The U.S. Environmental Protection Agency (EPA) has issued two proposed rulemakings, following through on this administration’s promise to roll back drinking water regulations for per- and polyfluoroalkyl substances (PFAS).
The proposed rules, published in the Federal Register today, formalize the plans EPA laid out in a May 14, 2025 press release. The first rule (Compliance Extension Rule) proposes to extend the deadline to comply with drinking water standards for the PFAS compounds PFOA and PFOS from April 26, 2029 to April 26, 2031. The second rule (Rescission Rule) proposes to rescind the regulatory determinations and related provisions for the PFAS compounds PFHxS, PFNA, HFPO-DA (GenX), and PFBS. These rules would serve to modify existing regulations that EPA finalized for PFAS under the Safe Drinking Water Act in April 2024.
PFAS are a class of thousands of chemicals that are water-, oil-, and heat-resistant, and have been produced and used since the 1940s in countless consumer and industrial products. The resilient characteristics of these compounds have led to their widespread use in products including cosmetics, water- and stain-resistant clothing, carpets, plastics, firefighting foam, and much more. PFAS exposure has been linked to a number of health concerns, including certain cancers, thyroid issues, liver and heart impacts, and developmental impacts in infants and children.
On April 10, 2024, the EPA announced finalization of the first-ever national drinking water standards for PFAS. That final rule set enforceable limits for five individual PFAS and mixtures of a combination of up to four PFAS in drinking water.
The rule set the following enforceable standards, called maximum contaminant levels (MCLs), for the newly regulated PFAS compounds:
| Compound | Final MCL |
| Perfluorooctanoic acid (PFOA) | 4.0 parts per trillion (ppt) (also expressed as ng/L) |
| Perfluorooctane sulfonic acid (PFOS) | 4.0 ppt |
| Perfluorohexanesulfonic acid (PFHxS) | 10 ppt |
| Perfluorononanoic acid (PFNA) | 10 ppt |
| Hexafluoropropylene oxide dimer acid (HFPO-DA; commonly known as GenX Chemicals) | 10 ppt |
| Mixtures containing two or more of PFHxS, PFNA, HFPO-DA, and perfluorobutanesulfonic acid (PFBS) | 1 (unitless)
Hazard Index |
These standards apply to public water systems (defined in the Safe Drinking Water Act and its implementing regulations), that are either community water systems (i.e., serve year-round residents) or non-transient, non-community water systems (i.e., are not community water systems and regularly serve at least 25 of the same people over six months per year).
Under the original regulations (currently in effect), EPA gave water systems five years—until April 26, 2029—to comply with the MCLs. This reflected a discretionary two-year extension to the statute’s three-year default compliance deadline for MCLs.
The Compliance Extension Rule does not provide an automatic two-year compliance extension to 2031 for all regulated water systems. It instead offers water systems the opportunity to request the additional time to comply with the enforceable limits. To be eligible to seek the federal exemption, a drinking water system must be:
- Subject to the 2024 PFAS drinking water regulation;
- In operation on or before June 25, 2024;
- Not currently under a small system variance pursuant to Safe Drinking Water Act section 1415(e) for the PFOA and PFOS MCLs; and
- Located in a state, territory, or Tribe that does not have primary enforcement authority (or “primacy”) for the 2024 PFAS drinking water regulation.
If a water system is located in a state, territory, or Tribe that has primacy for the 2024 PFAS drinking water regulation, the system could request an exemption from the appropriate state, territory, or Tribal drinking water agency. Notably, once a state, territory, or Tribe obtains primacy for the 2024 PFAS regulation, EPA cannot grant new federal exemptions to water systems in that location. It will be up to the state, territory, or Tribe to determine whether it will allow previously granted federal exemptions to continue.
Another factor for water systems to consider under the Compliance Extension Rule is that water systems with PFOA or PFOS levels above 12 ppt must take measures to reduce consumers’ exposure (e.g., by providing drinking water filters) during the exemption period.
EPA has developed FAQs on the Compliance Extension Rule for drinking water primacy agencies and public water systems.
Under the Rescission Rule, EPA proposes to rescind its regulatory determinations to regulate PFHxS, PFNA, and HFPO-DA individually and mixtures of these three PFAS and PFBS. EPA published its final regulatory determinations for these four PFAS simultaneously with its April 2024 final rule establishing regulatory requirements (e.g., monitoring, reporting, and MCL compliance) for the compounds.
The Agency now contends that under the best reading of the Safe Drinking Water Act, EPA is not authorized to make a final regulatory determination and issue the resulting, final regulatory requirements simultaneously. The Agency intends the Rescission Rule to correct what it now claims was an unlawful procedure for establishing regulatory requirements for PFHxS, PFNA, HFPO-DA, and PFBS. Importantly, the Agency affirms its commitment to consider additional PFAS (including those currently proposed for rescission) for future drinking water regulation and acknowledges that this may result in more stringent requirements.
The deadline for public comments for both rules is July 20, 2026. The EPA is holding a virtual public hearing, during which it will present information on the proposed rules and accept verbal public comments, on July 7, 2026.