EPA Relaxes PFAS Drinking Water Standards, Cost Implications Remain
The U.S. Environmental Protection Agency (EPA) has confirmed it will maintain the maximum contaminant levels for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) at 4 parts per trillion under the Safe Drinking Water Act. These legally enforceable standards, finalized in 2024, remain in effect as litigation continues.
At the same time, the agency announced plans to extend the compliance deadline from 2029 to 2031, establish a federal exemption process, and launch a PFAS outreach initiative to assist small and rural water systems. These efforts respond to concerns from utilities, regulators and Congress over the financial and operational strain of meeting the 2029 timeline.
In a significant shift, the EPA also plans to rescind the maximum contaminant levels for four additional PFAS substances—PFHxS, PFNA, GenX (HFPO-DA) and PFBS––both individually and as a mixture under the Hazard Index. The previous administration used the Hazard Index, a tool for assessing health risks from oral exposure to chemical mixtures, to establish these standards. The agency has now signaled that this mixture approach is not consistent with the standard-setting process of the Safe Drinking Water Act.
The EPA is expected to propose the revised compliance rule in fall 2025, with final action anticipated by spring 2026.
Implications for ILMA Members
While these regulations apply directly to drinking water systems, they underscore the EPA’s continued focus on PFAS water contamination. The decision to maintain strict PFOA and PFOS limits indicates sustained regulatory pressure on the matter. Additionally, the stringency of these standards has technical and financial implications for ILMA members that rely on municipal water systems.
Achieving compliance will require water systems to install costly treatment technologies––such as granular activated carbon filtration or reverse osmosis––with costs likely to be passed along to ratepayers. Importantly, such technologies also reduce many other PFAS compounds, including the ones that EPA will not seek to regulate. Thus, the costliest elements of the rule remain intact despite other rollbacks.
Members should assess potential PFAS exposure from incoming water sources and ancillary fluid use. The EPA’s Unregulated Contaminant Monitoring Rule database may help identify whether certain water systems have detected unregulated PFAS.
ILMA’s PFAS Task Force continues to monitor developments to provide best practices guidance to members.