Changes to U.S. EPA PFAS Drinking Water Standards Under the Trump Administration

In April 2024, the United States Environmental Protection Agency (U.S. EPA) finalized Maximum Contaminant Levels (MCL) for five per- and polyfluoroalkyl substances (PFAS): perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and hexafluoropropylene oxide dimer acid (HFPO-DA or GenX), and PFAS mixtures containing at least two or more of PFHxS, PFNA, HFPO-DA, and perfluorobutanesulfonic acid (PFBS) using a Hazard Index to account for the combined and co-occurring levels of these PFAS in drinking water. The following table summarizes each compound or mixture and the MCL for that compound or mixture.

After review, U.S. EPA announced in a press release on May 14, 2025 that the agency will keep the current MCL for PFOA and PFAS. However, U.S. EPA intends to rescind the regulations and reconsider the regulatory determinations for PFHxS, PFNA, HFPO-DA, and the Hazard Index mixture. Further, U.S. EPA intends to extend the PFOA and PFOS MCL compliance deadlines to 2031 and establish a federal exemption framework.

U.S. EPA plans to initiate enhanced outreach to water systems, especially in rural and small communities, through its PFAS OUTreach Initiative (PFAS OUT). This is in response to comments and concerns from rural water systems that there are insufficient resources to monitor and mitigate PFAS in small water systems. U.S. EPA actions are intended to reduce the burden on drinking water systems and the cost of water bills, all while continuing to protect public health and ensure that the agency is following the law in establishing regulations such as these. Look for official changes in the Federal Register in the upcoming weeks.

What does this mean for Industry?

Based on the U.S. EPA press release on April 28, 2025 the agency intends to establish effluent limitation guidelines (ELGs) based on the PFOA and PFOS MCL. Look for additional information in a future 4TR article that will provide a move comprehensive summary of what U.S. EPA intends for PFAS regulation across multiple programs.

As we have seen, the Trump Administration is reviewing multiple programs and rules under U.S. EPA. Expect to see additional guidance and rulemaking in the next several months which will allow for additional comment from the regulated community.

ALL4 will continue to keep you informed on changes and updates to the ever-changing PFAS landscape. If you have any questions regarding PFAS at your facility, please reach out to Kayla Nuschke at knuschke@all4inc.com or Lizzie Smith at lsmith@all4inc.com.