On May 18, 2026, the U.S. EPA proposed rescinding portions of the 2024 PFAS National Primary Drinking Water Regulation (NPDWR) that applied to four PFAS contaminants (four analytes and a mixture group of analytes):
- PFHxS (perfluorohexane sulfonic acid)
- PFNA (perfluorononanoic acid)
- HFPO-DA (also known as “GenX chemicals”
- and the Hazard Index mixtures involving PFHxS, PFNA, HFPO-DA, and PFBS.
The standards under the NPDWR were originally finalized in April 2024 by the Biden Administration. The new proposed rule would remove: the regulatory determinations for PFHxS, PFNA, HFPO-DA, and the Hazard Index mixture, the associated maximum contaminant levels (MCLs), and related compliance and monitoring requirements tied to those compounds. EPA is not proposing any changes to the drinking water standards for PFOA and PFOS – the MCLs for those two compounds will remain at 4 ppt each. The EPA separately proposed extending compliance deadlines from 2029 to 2031 for qualifying water systems.
EPA stated the proposal is intended to address what it describes as procedural deficiencies under the Safe Drinking Water Act (SDWA) in the original rulemaking process. EPA argues the prior administration did not properly follow SDWA procedural requirements when issuing the regulations for the four PFAS categories being rescinded. The proposal is focused on correcting the “unlawful process” used in the original rulemaking process. Digging into the details further, the EPA states the previous administration proposed the decision to regulate certain PFAS and proposed the actual MCLs at the same time, instead of separate sequential steps. The current administration EPA states the SDWA requires:
- A preliminary “regulatory determination” that a contaminant should be regulated
- A public comment period on that determination
- Then a final determination
- Only afterward can EPA propose the actual MCLs and treatment requirements
What Does That Mean for the Environmental Monitoring Market?
For water utilities, it can change the monitoring and treatment obligations for those compounds, although PFOA and PFOS monitoring would remain. Results from the Fifth Unregulated Contaminant Monitoring Rule (UCMR5) are nearly complete, and for water utilities, the proposed rescinded contaminants were detected in very few public water systems (PWSs). In some cases, exceedances of the MCLs for PWSs were less than 0.1% (PFNA).
Here’s the link to the UCMR5 results: https://www.epa.gov/system/files/documents/2023-08/ucmr5-data-summary_0.pdf
For environmental services/consulting and laboratories, the proposed change will create some uncertainty for PFAS analytical demand, impacts to long-term compliance monitoring programs, and PFAS treatment and remediation investment strategies. Many states have their own existing state drinking water standards for PFAS that include some of those proposed rescinded contaminants. The proposed rule would further complicate the patchwork of PFAS drinking water standards in the US.
The environmental monitoring business is driven by changes in state and federal environmental regulations. At SGS, it’s our job to help our clients navigate this ever-changing regulatory landscape.
With 10 PFAS laboratories across North America, we are uniquely positioned to assist our clients with all their PFAS challenges.