Proposed PFAS Rescission Rule

On this page:

• Proposed Rule Summary
• Proposed Rule Supporting Materials
• Questions and Answers on the Proposed Rule
• Background
• Further Information 

Proposed Rule to Rescind Regulatory Determinations and Regulations for PFHxS, PFNA, HFPO-DA, and Hazard Index Mixtures

Proposed Rule Summary

On May 18, 2026, the EPA announced a proposed rulemaking to correct the Biden Administration's failure to follow the clear requirements of the Safe Drinking Water Act (SDWA) in promulgating regulations for perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid and its ammonium salt (HFPO-DA) (commonly knows and GenX chemicals), and Hazard Index mixtures of these three PFAS plus perfluorobutane sulfonic acid (PFBS). 

Following the proposed rule publishing in the Federal Register, the EPA will accept written comments on the proposed rule in the public docket for 60 days at www.regulations.gov under Docket ID: EPA-HQ-OW-2025-0654. 

The EPA will hold a virtual public hearing on July 7, 2026 where the public is invited to provide the EPA with verbal comments on the proposed rule. During the hearing, the agency will present information on the proposed rule and then receive comments from the public. Registration to attend and/or provide verbal comment during the hearing is required and the last day to pre-register to provide public comment is July 1, 2026. Information and registration for the public hearing is available here. The EPA will post an agenda and list of pre-registered public commenters to this website no later than July 6, 2026. For questions related to the public hearing, please contact PFASNPDWR@epa.gov. 

The EPA is also currently proposing a rule to extend the compliance deadlines for the PFOA and PFOS Maximum Contaminant Levels (MCLs). The public hearing for that proposed rulemaking will be held sequentially with this proposed PFAS rescission rule. For those interested in attending and/or providing verbal public comment on both rules, there is a combined registration process. However, please note that each separate rule proposal has an individual rulemaking docket for written comments. Please ensure any written comments are submitted the specific docket associated with your comments.

Proposed Rule Supporting Materials

• Pre-publication Federal Register Notice: Rescission of Regulatory Determinations and Removal of Related Provisions for Four PFAS Substances (PFHxS, PFNA, HFPO-DA, and the Mixtures of these Three PFAS plus PFBS) (pdf) (393.94 KB)
• Additional supporting information is available in Docket ID: EPA-HQ-OW-2025-0654

Questions and Answers on the Proposed Rule

Why is the EPA proposing to rescind its determinations and regulations for PFHxS, PFNA, HFPO-DA and Hazard Index mixtures of these three PFAS plus PFBS?

The EPA's proposal is necessary to correct the unlawful procedure under which regulations for these PFAS were promulgated. The EPA's proposal is solely based on a need to correct this unlawful process.

Will the EPA regulate the same PFAS that it is rescinding in the future?

Once the EPA has taken final action to correct the unlawful process by rescinding the current regulations for PFHxS, PFNA, HFPO-DA, and Hazard Index mixtures of these three PFAS plus PFBS, the agency will take steps to follow through on its commitment to evaluate additional PFAS in drinking water for future regulation. While the EPA cannot pre-determine the outcome, it is possible that the result could be more stringent requirements. 

Background

On April 10, 2024, the EPA announced the final PFAS National Primary Drinking Water Regulation that included legally enforceable drinking water MCLs for PFOA and PFOS, as well as PFHxS, PFNA, HFPO-DA, and hazard index mixtures of these three PFAS and PFBS, requiring public water system MCL compliance by April 2029. In May 2025, the EPA then announced its intent to rescind the regulations and reconsider the regulatory determinations related to these four PFAS to ensure the determinations and any resulting drinking water regulation follow the Safe Drinking Water Act process. Additionally, in May 2025, the EPA announced its intent to extend the compliance deadlines for PFOA and PFOS and establish a federal exemption framework. The EPA is also currently proposing a separate rulemaking to extend the compliance deadline for PFOA and PFOS. For more information on that PFOA and PFOS extension proposed rulemaking, please see the Proposed PFOA and PFOS Compliance Extension Rule website.

Further Information

To learn more about PFAS and to find important background information to support understanding the details of specific actions the EPA takes to address PFAS and other emerging events related to PFAS.