With two proposed rules issued on May 18, the Trump Administration’s U.S. Environmental Protection Agency (EPA) followed through on its stated intent to rescind or extend the compliance date for Biden-era drinking water limits for per- and polyfluoroalkyl substances (PFAS) of concern.

Exposure to PFAS has been linked to cancer, impacts to the liver and heart, and immune and developmental damage to infants and children. PFAS are often referred to as “forever chemicals” due to their inability to break down in the environment or the human body.

In April 2024, EPA issued the first-ever national, legally enforceable drinking water standard to reduce Americans’ exposure to six PFAS: PFOA, PFOS, PFNA, PFHxS, and HFPO-DA (also known as GenX chemicals), as well as a limit for mixtures of any two or more of four PFAS: PFNA, PFHxS, PFBS, and GenX chemicals. These PFAS types are known to cause harm to human health and for their widespread environmental contamination.

Some estimates based on EPA contaminant testing data suggest that as many as 30 million Americans are served by water systems with PFAS concentrations exceeding limits for one of the four PFAS that EPA is now rescinding.

EPA Offers Extended Compliance Deadline for PFOA, PFOS Limits

The first of two proposed rules issued by EPA on Monday upholds the Biden-era drinking water Maximum Contaminant Levels (MCLs) for PFOA and PFOS while offering a pathway for drinking water systems to obtain a two-year extension, granting them until 2031 to comply with the enforceable limits. This extension would not be automatic; drinking water systems that wish to receive additional time would need to affirmatively seek the extension and meet specific criteria outlined in the rule.

EPA says the extension would allow drinking water systems the time required to diagnose the severity of contamination through robust sampling; evaluate various compliance options, including changing source water or installing new control systems; construct and test new controls, often including pilot studies; evaluate financing options; and train their workforce to support construction, operation, and maintenance. Additionally, allowing drinking water systems to seek additional time for this work could allow the cost of PFAS removal technologies to come down through technological advancements and production efficiencies.

EPA Rescinds Biden-Era Limits for PFAS in Drinking Water

The second proposed rule, if finalized, would officially rescind the limits set for PFHxS, PFNA, HFPO-DA, and the hazard index of these three plus PFBS, because the Biden Administration “failed to follow statutory requirements” for establishing regulations under the Safe Drinking Water Act (SWDA).

“SDWA requires a sequential approach to regulation, where the agency must first propose to regulate a particular drinking water contaminant and seek public comment on whether a regulation would be appropriate. Only after the public has had the opportunity to comment on that proposal and when the EPA has finalized a determination to regulate may the EPA publish a proposed regulation for that contaminant. Instead of abiding by that process set out in the SDWA, the Biden EPA combined steps simultaneously, which is not permitted,” justified EPA.

EPA added that, while it cannot “pre-determine the outcome” of future rulemaking, “the Trump EPA would deliver on its commitment to evaluate these PFAS for regulation under the SDWA and do it correctly by supporting transparency and following gold-standard science,” and that “it is possible that the result could be more stringent requirements addressing these PFAS in drinking water.”

Relatedly, in April 2026, EPA added PFAS to the Sixth Contaminant Candidate List (CCL 6) for drinking water, which the agency uses to identify priority contaminants for regulatory decision-making and information collection.

Stopping PFAS Contamination Before it Reaches Drinking Water

Alongside the issuance of the proposed rules, EPA announced that it is currently developing a proposed rule on technology-based effluent limitations and pretreatment standards for key industrial categories that discharge PFAS, including chemical manufacturers and other sources, to keep PFAS out of waterways. The agency expects to publish this proposed rule in the coming months.

EPA also said it is using its authorities under the Toxic Substances Control Act (TSCA) to ensure new and existing chemicals are subject to robust scientific review before they enter commerce. The agency is also looking to hold polluters accountable for legacy contamination consistent with the polluter-pays principle, but a durable statutory fix from Congress is necessary to achieve this goal.

Finally, EPA announced nearly $1 billion in new funding to states to address PFAS in drinking water and has made $5 billion available over five years through the Emerging Contaminants in Small or Disadvantaged Communities Grant. The agency underlined its ongoing work to develop, validate, and refine analytical methods for PFAS and identify and validate PFAS removal and destruction technologies.