California Water Views

On May 18, 2026, following through on its May 2025 announcements, the Trump administration, through the Environmental Protection Agency (EPA), proposed two new PFAS rules. The proposed rules are in keeping with the deregulatory spirit of the proposed rule narrowing PFAS reporting requirements proposed in November 2025. One proposed rule establishes a process for water systems to obtain an extension on compliance with the Maximum Contaminant Levels (MCLs) established in 2024 for PFOA and PFOS. The other rescinds drinking water standards for six other PFAS pending further review.

Environmental groups have criticized both rules as advancing industry and utility interests at the expense of public health and drinking water quality. For both, public comment closes July 20, 2026, and a public hearing will be held on July 7, 2026. The deadline to register to attend or provide public comment at the hearing is July 1, 2026. EPA intends to finalize both rules this year and is making billions of dollars in grants and technical assistance available to help water systems position themselves for compliance.

Proposed Rule to Delay MCL Compliance for PFOA and PFOS Until 2031

The first proposed rule would Extend the Compliance Deadline for PFOA and PFOS Maximum Contaminant Levels (MCLs). Specifically, EPA would establish an exemption framework under Safe Drinking Water Act (SDWA) sections 1416(f) and 1450(a)(1) that allows eligible public water systems to apply for an extension to the compliance deadlines for the MCLs for PFOA and PFOS from April 26, 2029, to April 26, 2031. The MCLs themselves—set at 4.0 parts per trillion (ppt) for each compound—remain unchanged from the 2024 PFAS National Primary Drinking Water Regulations (NPDWR).

The proposed federal exemption is expected to apply to approximately 66,000 public water systems (PWSs), including community water systems and non-transient non-community water systems, as well as state and Tribal agencies responsible for drinking water regulatory development and enforcement.

To qualify for the federal exemption, a PWS must (1) be located in a state that has not yet obtained primacy for the PFOA and PFOS MCLs; (2) have been in operation on or before June 25, 2024; and (3) not hold a variance from the 2024 PFOA and PFOS MCL requirements. Systems must certify that (1) they cannot comply with the MCLs by April 26, 2029, due to economic or other compelling factors; alternative water sources are unavailable; and (3) management changes or restructuring cannot reasonably achieve compliance.

A PWS that receives an extension but currently has PFOA or PFOS levels at or above 12 ppt must implement at least two interim control measures during the exemption period. Eligible control measures include (1) providing alternative water sources (including bottled water); (2) installing point-of-use or point-of-entry devices; (3) providing certified water filtration pitchers; (4) implementing source water controls; (5) distributing public education materials; and (6) conducting community outreach activities.

By alleviating certified operator availability challenges, financial limitations, and time pressures that exacerbate construction and equipment costs, EPA estimates that the proposed rule will produce annualized total cost savings between $15.7 million and $32.2 million for PWSs serving 10,000 or fewer persons.

Systems that need additional time beyond the two-year federal exemption may request their primacy agency grant a further exemption for up to one additional year, and smaller systems (serving fewer than 3,300 persons) facing financing difficulties may receive additional exemption renewals not to exceed six years.

Proposed Rule to Rescind MCLs for Six other PFAS

The second proposed rule would Rescind MCLs for PFHxS, PFNA, HFPO-DA, and the Hazard Index mixtures of these three PFAS plus PFBS. EPA argues that the Biden administration failed to comply with the sequential process required by the SDWA to establish these standards, leaving the regulations vulnerable to legal challenge. The Agency intends this proposed rule to make standards more legally secure and reduce uncertainty for regulated water systems.

If finalized, this rule will relieve PWSs of compliance costs arising from monitoring, treatment, and reporting of these chemicals in drinking water. EPA estimates these savings to be approximately $82 million annually but acknowledges that this rescission foregoes approximately $6.7 million per year in benefits.

The Agency plans to revisit the standards for these chemicals after finalizing the proposed rule, and notes that it may ultimately arrive at more stringent standards.

Conclusion

For water utilities, the practical takeaways from these proposed rules are clear. Systems that cannot meet the 2029 PFOA and PFOS federal compliance deadline have a defined pathway to request an additional two years. Systems that had been planning capital improvements to address PFHxS, PFNA, HFPO-DA or Hazard Index mixtures of these PFAS and PFBS may want to reassess those investments pending final action on the rescission rule, while keeping in mind that EPA has signaled these chemicals may be regulated again, potentially at more stringent levels. For water systems in California, these improvements may be necessary sooner, as the state Division of Drinking Water has stated that the development of standards for these PFAS is a priority. We will continue to track these rulemakings and report on final action as the year progresses.

Part II