On May 14, 2025, the U.S. Environmental Protection Agency (EPA) announced that it plans to retain the current drinking water standards for two per- and polyfluoroalkyl substances (PFAS), i.e., perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), but delay related compliance deadlines from 2029 to 2031. Notably, EPA now intends to rescind regulations for four other PFAS covered in the Biden-era PFAS drinking water rule. EPA plans to issue a proposed rule this fall and finalize the rule in early 2026.
On April 10, 2024, the EPA under President Biden established Maximum Contaminant Levels (MCLs)1 and Maximum Concentration Level Goals (MCLGs)2 for six PFAS (the MCL Rule), including PFOA and PFOS, which gave public water systems until 2029 to complete water treatment system adjustments and infrastructure upgrades, as may be necessary, to comply with the MCLs.3 EPA now plans to develop a rulemaking to extend the compliance date to 2031 and rescind the regulations for PFHxS, PFNA, HFPO-DA (commonly known as GenX), and the Hazard Index mixture of these three plus PFBS. EPA also stated that it will support the defense of the MCL Rule with respect to PFOA and PFOS in the ongoing legal challenges to the rule.4 In its May 14, 2025 announcement, the agency hinted at “holding polluters accountable”, stating that “the need for a polluter pays model has guided a lot of the work to be done at EPA in the future.”
Environmental groups criticized the announcement, expressing concerns about the impact on public health and stating that the plans are in violation of the Safe Drinking Water Act’s “anti-backsliding provision.”5 Industry groups applauded the EPA’s stance as necessary and pragmatic. The Association of State Drinking Water Administrators responded that with the current 2029 deadline under the Biden-era MCL Rule, “states and water systems are struggling with the timeframes to complete the pilot testing, development of construction plans, and building the necessary treatment improvements.”
The EPA’s May 14, 2025 announcement can be found here.
1 MCLs are the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to MCGLs as feasible using the best available treatment technology and taking cost into consideration. MCLs are enforceable standards.
2 MCLGs are the level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety and are non-enforceable public health goals.
3 Under the MCL Rule, the MCL for PFOA and PFOS in drinking water supplies is 4 parts per trillion and the MCLG is zero. For the four other chemicals, EPA had set the MCLs and MCLGs at 10 parts per trillion.
4 The MCL Rule is currently being challenged in the D.C. Circuit court by industry groups and utilities. See American Water Works Association, et al v. EPA, et al (24-1088) (D.C. Court of Appeals)
5 Section 1412(b)(9) of the Safe Drinking Water Act as amended in 1996 requires that: "The Administrator (of EPA) shall, not less often than every 6 years, review and revise, as appropriate, each national primary drinking water regulation promulgated under this title. Any revision of a national primary drinking water regulation shall be promulgated in accordance with this section, except that each revision shall maintain, or provide for greater, protection of the health of persons." 42 U.S.C. § 300g-1(b)(9) (1996) See the Safe Drinking Water Act here.
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