EPA Proposes Rescinding PFAS National Drinking Water Regulations

The United States Environmental Protection Agency (“EPA”) issued two proposed rules on May 20, 2026, seeking to partially unwind the requirements imposed under the current National PFAS Drinking Water Regulations promulgated in 2024:  (1) first, EPA proposes rescinding the Maximum Contaminant Levels (“MCLs”) for three PFAS substances and a Hazard Index for a mixture of PFAS constituents; and (2) second, EPA proposes providing an opportunity for entities subject to the rule to extend the compliance deadline by two years.

Specifically, EPA’s proposal this month would take the following actions:

1. Rescind the MCLs for perfluorohexane sulfonic acid (“PFHxS”), perfluorononanoic acid (“PFNA”), hexafluoropropylene oxide dimer acid (“HFPO-DA,” or commonly known as GenX chemicals), and the Hazard Index mixture of these three PFAS substances combined with perfluorobutane sulfonic acid (“PFBS”) (“Index PFAS”); and
2. Allow public drinking water systems (“PWS”) to request two additional years—from April 26, 2029, to April 26, 2031—to comply with the enforceable limits for MCLs for perfluorooctanoic acid (“PFOA”) and perfluorooctane sulfonic acid (“PFOS”).

First Proposal: Rescinding Certain PFAS MCLs and Hazard Index

The proposed rule explains that EPA believes it previously “promulgated an unlawful drinking water standard by proposing and finalizing a drinking water standard for PFHxS, PFNA, HFPO-DA and the Index PFAS without following the stepwise process mandated by Congress.”

Therefore, EPA proposes rescinding the MCLs for these three PFAS constituents and the Index PFAS.  Below is a table of EPA’s proposed updates to the regulations promulgated on April 10, 2024:

Second Proposal: Extending PWS Compliance Deadlines

Under the current National PFAS Drinking Water Regulations, any regulated PWS, which includes community water systems and non-transient non-community water systems, has until April 26, 2029, to comply with the MCLs for PFOA and PFOS.  The proposed rule retains this compliance deadline, but allows a PWS to apply for a two-year extension to comply until April 26, 2031.

The proposed rule explains that EPA is “aware that many systems may be unable to comply with the MCLs by the current 2029 compliance date.”  Therefore, “EPA is proposing to exempt eligible systems from the . . . compliance deadlines, and instead extend these deadlines to provide greater regulatory flexibility and support for addressing these PFAS in drinking water . . .” 

Next Steps: Public Comments and Hearing

Before the proposed rules take effect, EPA is seeking public comment.  All public comments must be received by July 20, 2026.  The rule proposing to rescind certain MCLs outlines the areas where EPA is specifically seeking public comments at pgs. 29420-29421; the rule proposing to establish a compliance extension outlines the areas where EPA is specifically seeking public comment at pgs. 29441-29442.

Additionally, EPA will hold a virtual public hearing regarding both proposed rules on July 7, 2026.  Details regarding the topics of discussion and the anticipated schedule are on page 29421 of the rule proposing to rescind certain MCLs, and on page 29442 of the rule proposing to establish the compliance extension.  EPA has also included information regarding this hearing on a related website.

For more information regarding what these proposed rules mean for your business, please contact Erin Brooks, Christian Bromley, Daron Ravenborg, John Kindschuh, or any member of the PFAS team.