The U.S. Environmental Protection Agency (EPA) has unveiled two closely linked proposed rulemakings that would reshape the federal government’s approach to regulating per- and polyfluoroalkyl substances (PFAS) in drinking water.
Announced May 18, the proposals would rescind portions of the Biden administration’s 2024 PFAS drinking water regulations covering four PFAS compounds and related mixtures, while separately extending compliance deadlines for public water systems dealing with two of the most widely studied PFAS — perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS).
Together, the proposals mark a significant shift in how the Trump administration intends to implement the Safe Drinking Water Act (SDWA) while continuing federal oversight of PFAS contamination.
EPA Administrator Lee Zeldin said the Biden administration “cut corners and failed to follow the law” in establishing portions of the 2024 PFAS National Primary Drinking Water Regulation.
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“We are fixing that error with standards water systems can actually implement and that will hold up to scrutiny, while addressing PFOA and PFOS, two of the best-studied PFAS with well-documented health impacts,” Zeldin said in a statement.
EPA seeks to rescind four PFAS standards
One proposal would rescind regulatory determinations and drinking water standards for perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA), commonly known as GenX chemicals, and hazard index mixtures involving those compounds plus perfluorobutane sulfonic acid (PFBS).
The EPA argues the Biden administration failed to follow the sequential rulemaking process required under the SDWA. According to the agency, regulators improperly combined the contaminant determination phase with the rule proposal stage, depriving the public of an opportunity to comment on whether regulation of those substances was appropriate before enforceable standards were proposed.
The agency said the procedural issue leaves the regulations legally vulnerable and creates uncertainty for drinking water systems attempting to comply.
If finalized, the rescission would remove the current standards while EPA re-evaluates those PFAS compounds through what it describes as a legally defensible and science-based process. The agency noted that future standards could ultimately become more stringent.
The proposed rollback comes as several industry groups continue to challenge the PFAS rules in court. The American Chemistry Council and the National Association of Manufacturers filed a joint lawsuit arguing the regulations were “arbitrary, capricious and an abuse of discretion.”
At the same time, water utility organizations, including the American Water Works Association (AWWA) and the Association of Metropolitan Water Agencies (AMWA) also challenged the rules, though largely over cost concerns and the burden placed on municipal systems and ratepayers.
In a joint statement, AWWA CEO David LaFrance and AMWA CEO Tom Dobbins said drinking water regulations must be developed within the “rigorous, science-based framework” established under the SDWA.
The organizations said the new proposals would provide an opportunity for additional public input while supporting “more scientifically robust drinking water standards.”
Compliance deadline for PFOA and PFOS could move to 2031
A separate proposed rule would preserve the existing maximum contaminant levels (MCLs) for PFOA and PFOS at 4 parts per trillion each, but would allow eligible water systems to seek a two-year extension to comply.
Under the original 2024 regulation, systems were required to meet the standards by April 2029. The proposed extension framework would move the deadline to April 2031 for systems granted federal exemptions.
EPA emphasized the extension would not be automatic. Water systems would need to apply for additional time and demonstrate legitimate implementation challenges.
The agency said utilities often require years to complete sampling, evaluate treatment alternatives, secure financing, construct infrastructure and train operators before full compliance can be achieved.
EPA also argued the additional time could reduce long-term costs as PFAS treatment technologies continue to mature and become more affordable.
Systems granted exemptions would still be required to conduct monitoring and public reporting. Utilities with PFOA or PFOS concentrations at or above 12 parts per trillion would also be required to implement interim mitigation measures during the exemption period.
EPA said community water systems operating under exemptions would need to notify customers through annual public notices and consumer confidence reports explaining why the exemption was granted and outlining steps being taken to achieve compliance.
Federal funding and treatment technologies highlighted
Alongside the proposed rules, EPA announced nearly $1 billion in additional grant funding through the Emerging Contaminants in Small or Disadvantaged Communities Grant program. The agency said the latest funding brings the total available through the program to $5 billion over five years.
EPA also highlighted ongoing efforts to reduce PFAS contamination at the source through industrial discharge limits, wastewater pretreatment standards and chemical reviews under the Toxic Substances Control Act.
The agency said it is continuing to evaluate and deploy PFAS treatment and destruction technologies including granular activated carbon, ion exchange resins, reverse osmosis, supercritical water oxidation and electrochemical oxidation.
EPA cited four full-scale PFAS treatment systems completed for the Irvine Ranch Water District and the Orange County Water District in southern California, which the agency said are protecting more than 9,500 households.
Both proposed rules are open for public comment until July 20, 2026. EPA plans to hold a virtual public hearing on July 7, 2026.
