On May 20, 2026, the U.S. Environmental Protection Agency published a proposed rule that would extend the compliance deadline for the Maximum Contaminant Levels (MCLs) applicable to perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in drinking water. Under the proposal, the current compliance date of April 26, 2029, would be moved to April 26, 2031, providing an additional two years for affected public water systems to achieve full compliance with these standards under the National Primary Drinking Water Regulations.
The proposed extension is significant because it directly affects the planning horizon for public water systems that have been preparing to meet the PFOA and PFOS MCLs. For many systems, compliance requires substantial capital investment, treatment technology upgrades, source water evaluations, and coordination with state regulators and local governments. The proposed timeline shift could provide meaningful relief, particularly for systems navigating procurement challenges, financing constraints, or engineering lead times associated with implementing PFAS treatment infrastructure.
A critical feature of the proposal is that the extension is not automatic. Relief would be available only to public water systems that affirmatively submit a request to the EPA. Systems that fail to make such a request would remain subject to the original April 26, 2029 compliance date. Accordingly, public water systems should evaluate, well in advance of the existing deadline, whether seeking an extension aligns with their compliance strategy, capital planning, and operational realities.
Given the proposal's potential effect on long-term compliance planning, public water systems and the municipalities, utilities, and authorities that operate them should begin assessing their position now. Key considerations include the current status of PFAS monitoring data, the projected timeline for treatment system design and construction, anticipated funding sources, and the procedural requirements that the final rule may impose on extension requests. Stakeholders may also wish to monitor the rulemaking docket and consider submitting public comments to inform the final rule.
Counsel can assist in evaluating compliance obligations, preparing extension requests, and developing a coordinated regulatory strategy as the rulemaking progresses.
This alert is for general informational purposes only and does not constitute legal advice. Clients facing PFOA and PFOS compliance questions should seek tailored advice based on their specific circumstances.