By Amanda Canida, Senior Drinking Water Process Engineer and PFAS and Ozone Technology Leader and Adam Feffer, Senior Drinking Water Process Engineer and National PFAS Practice Leader, Black & Veatch

Proposed rules by the U.S. Environmental Protection Agency (EPA) have the potential to significantly alter regulation of per- and polyfluoroalkyl substances, or PFAS. While headlines have framed the proposed rules as wholesale regulatory relief, the reality is nuanced.

The Black & Veatch 2026 Water Report revealed that cost has overtaken regulatory uncertainty as the top barrier to PFAS action: 31% of utilities surveyed for the report that said they're addressing PFAS cite budget and ratepayer considerations as the greatest limiting factor, compared with 25% citing regulatory uncertainty.

With that insight, here's what U.S. drinking water utilities need to know - and do - now.

Limits and timing proposals could reshape PFAS drinking water regulation

EPA is proposing two separate rules to modify the 2024 PFAS National Primary Drinking Water Rule (NPDWR). Each action targets specific PFAS:

• Rescission of limits and regulatory determinations for GenX, PFHxS, PFNA and the Hazard Index. The EPA published the preliminary regulatory determinations for PFHxS, PFNA, GenX Chemicals, and PFBS at the same time the proposed PFAS NPDWR was released in March 2023. The EPA published the final regulatory determinations for PFHxS, PFNA, GenX Chemicals, and the HI at the same time the final PFAS NPDWR was released in April 2024. The EPA acknowledged that they interpreted the processes taken to accelerate rulemaking of these constituents were unlawful per the Safe Drinking Water Act (SDWA), which requires two separate public comment periods, with one for the preliminary regulatory determination and another for the proposed rule. With this proposed rule, EPA is seeking to address the issue on two levels: rescinding the specific limits and the regulatory determinations for these PFAS.

• Compliance extension. The 4-parts-per-trillion (ppt) limits for PFOA and PFOS will remain, as the proper SDWA rulemaking procedures were followed for these two (2) PFAS. But water systems can request two additional years, pushing the compliance deadline from April 2029 to April 2031 through a federal exemption process until their states obtain primacy.

Relief, perhaps, but there are two critical considerations.

First, rescission does not mean "no regulation." EPA has stated that once it withdraws the GenX, PFHxS, PFNA, and Hazard Index rules, it will re-evaluate those compounds through the proper Safe Drinking Water Act process. The agency has been explicit: The outcome could be more stringent requirements than the current rule.

Second, the extension is not automatic. A water system cannot simply wait until 2031. It must apply for an extension – which in effect is an exemption – by saying it cannot meet eligibility criteria and certifying in writing that it cannot comply by 2029 due to economic, technical or logistical constraints. Systems must notify EPA of their intent to seek an extension/exemption within 180 days of the final rule promulgation.

Five compliance considerations

Utilities that misinterpret the proposed rules as permission to not act on PFAS contamination may find themselves behind when the new rules go into effect. Following are compliance details that are critical for utilities to consider.

1. The procedural argument is consequential.

EPA's rationale for rescinding the four PFAS limits stems from an incorrect initial interpretation of the SDWA. The revised interpretation includes requirements for a sequential process: first a preliminary regulatory determination with public comment, then a final determination and only then a proposed regulation with a second public comment period. The proposed regulation can happen in parallel with the final regulatory determination or within 18 months. The 2024 rule collapsed these steps. It issued preliminary determinations in parallel with the proposed rule and final determinations in parallel with the final rule.

This matters beyond the four PFAS compounds. EPA has preemptively argued that its rescission does not trigger the SDWA's anti-backsliding provision — a signal that the agency expects legal challenge.

The implications of these rescinded regulations are minimal, with an estimated 0.6 percent of water systems triggered into action by the four PFAS included in the Hazard Index that weren’t already triggered by the PFOA or PFOS regulations. For that fraction of water systems, there is risk that the proposed rule will not be promulgated, perhaps benefitting continued project progress.

2. There are a number of compelling factors that justify the need for additional time.

The EPA acknowledged that additional time may be required for systems to comply with the NPDWR due to economic, technical, and/or logistic limitations. EPA cited 20 percent inflation in construction materials for public water system equipment between 2024 and 2025, along with procurement uncertainty and supply chain concerns for steel and adsorptive media used for PFAS applications, respectively. There are also ongoing workforce shortages with current operational requirements, which will inherently increase with added treatment complexity at a number of facilities. Financial hardships and funding timelines also influence allowable project timelines. The EPA indicated this additional time will provide them with more time to provide financial and technical support for disadvantaged communities.

3. State primacy is a game changer.

Federal exemptions apply only to systems in states that have not yet obtained primacy for the PFAS rule. Once a state gains primacy, federal exemptions can no longer be granted. Authority shifts to the state primacy agency.

Once a state obtains primacy, they can determine whether to provide additional exemptions consistent with the SDWA. States may choose not to allow federal exemptions to continue. If current state laws prohibit exemptions, the federal framework does not apply.

It is important for public water systems to coordinate with their state primacy agency to confirm timing and contents of primacy package submission. Confirm if exemptions are allowable in your state and if so, what their approach will be for continuing extensions after obtaining primacy. If your projects cannot meet the 2031 exemption deadline, initiate dialogue with primacy agencies regarding potential administrative/consent orders.

4. Interim obligations are extensive, even with the extension.

Systems with PFOA or PFOS detections at or above 12 ppt must implement at least two interim control measures throughout the exemption period. Options include providing certified pitcher filters and two years of replacement cartridges, supplying bottled water or temporary alternative sources, installing and maintaining point-of-use or point-of-entry treatment devices, pursuing source water controls, distributing public education materials, and conducting community educational outreach activities. Only one of the two required control measures can include public education/outreach.

5. Public notification requirements are required.

The public notification requirements match those required for the SDWA. Public notification requirements carry risk of damaged customer confidence. Public water systems should consider proactive public education materials, potentially through public relations firms.

6. PFAS liability extends beyond drinking water

PFOA and PFOS remain designated as CERCLA hazardous substances — a designation the current administration retained. EPA is working with the U.S. Congress on a liability framework for "passive receivers" of PFAS contamination, but no statutory fix exists yet.

The PFAS compliance clock continues to tick

Utilities face a layered landscape of federal proposals, state-level variability, potential interim obligations and the potential that GenX and related compounds will be regulated again. The systems positioned to navigate this moment are those treating the extension as a planning accelerator, not a pause button. Next steps include:

• Submitting public comments and/or participating in hearings

• Advancing PFAS projects

• Determining timing required to get treatment online in comparison to current project schedule

• Pursuing an exemption if needed

• Studying the feasibility of temporary treatment systems

• Considering collaborative delivery strategies like progressive design-build or construction manager at risk (CMAR) and pre-procurement of long lead items.

Key dates

• July 7, 2026 — EPA virtual public hearing on both proposed rules

• July 20, 2026 — Public comment deadline

• November 2027 — Final regulations expected