EPA Announces Rulemaking to Rescind SDWA Drinking Water Limits for Certain PFAS

On May 18, EPA published a proposed Safe Drinking Water Act (SDWA) rule (available here) that would rescind the portions of the Biden Administration EPA’s 2024 PFAS National Primary Drinking Water Regulations pertaining to perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid and its ammonium salt (HFPO-DA, commonly known as GenX chemicals), and mixtures of these three PFAS plus perfluorobutane sulfonic acid (PFBS), including the final Maximum Contaminant Levels (MCLs) for those PFAS. The proposed rule would not affect the MCLs or other SDWA regulations for PFOA and PFOS, which were also regulated under the 2024 rulemaking.

The basis for the new rule is EPA’s assertion that the Biden Administration “followed an unlawful procedure” in promulgating the MCLs and associated regulations for these PFAS. EPA concedes that the cost savings for public water systems due to this rescission will only total approximately $11.6 million per year, nationwide, whereas the expected benefit of regulating these PFAS under the SDWA had been estimated at approximately $6.7 million per year.

A public hearing on the proposed rule will be held on July 7, 2026. Written comments may be submitted until July 20, 2026.