Trump EPA Rolling Back Certain PFAS Limits in Drinking Water

On May 14, 2025, EPA announced it will rescind and reconsider regulations setting maximum contaminant levels (MCLs) in drinking water for shorter chain per- and polyfluoroalkyl substances (PFAS) and extend the deadlines for compliance with the MCLs for the longer chain substances, see here.

Background

In April of 2024, the Biden EPA issued a final rule (PFAS MCL Rule) setting legally enforceable MCLs in drinking water for the following PFAS substances:

• PFOA and PFOs (longer chain PFAS): MCLs of 4.0 parts per trillion (ppt), individually
• PFNA, PFHxS, PFBS and HFFPO-DA (GenX):  MCLs of 10 ppt
• Any mixture of two or more of PFNA, PFHxS, PFBS, and GenX Chemicals: limit must be set by water systems using a hazard index calculation to assess overall risk.

The PFAS MCL Rule also required public water systems to monitor for these PFAS from 2024-2027 and to continue to monitor thereafter to show compliance with the new limits. If monitoring shows these systems are exceeding the limits, systems were required to reduce these PFAS or put in a treatment system to meet the limits by 2029.

EPA was sued by various water utilities and chemical companies challenging the rule based on the lack of scientific support and cost analysis, among other issues.  After the November election, EPA asked the U.S. Court of Appeals for the D.C. Circuit to hold the cases in abeyance so it could decide whether the new administration’s EPA would revisit any of the PFAS MCL Rules’ requirements.  The last abeyance granted by the court is set to expire on June 4, 2025.

In April of 2025, newly Trump-appointed EPA administrator Lee Zeldin issued a press release stating that EPA would be looking at the Biden drinking water standards for these PFAS and making some changes.

What Now

In its May 14, 2025, press release, EPA went one step further, stating its plan to keep the MCLs of 4 ppt for PFOAS and PFOS, rescind those for PFNA, PFHxS, PFBS and HFFPO-DA, and to extend compliance deadlines for drinking water systems to comply from 2029 to 2031. EPA also stated it will “establish a federal exemption framework, initiate enhanced outreach to water systems, especially in rural and small communities…” Administrator Zeldin stressed that the goal of the new EPA is to alleviate the burdens placed on passive receivers such as public water systems and hold the “polluters” responsible. To enhance engagement, EPA will launch PFAS OUT to connect with every public water utility that needs capital improvements to address PFAS in their systems.

EPA plans to propose a new PFAS drinking water rule in the fall of 2025 and hopes to finalize it by the spring of next year.