If your role has anything at all to do with drinking water, you are no doubt aware that the U.S. EPA announced plans to rescind the individual limits on HFPO-DA (GenX), PFHxS, and PFNA and the Hazard Index limit for HFPO-DA, PFHxS, PFNA, and PFBS under the National Primary Drinking Water Regulations (NPDWR). In addition, they announced plans to extend the deadline for compliance with PFOA and PFOS Maximum Contaminant Levels (MCLs) from 2029 to 2031.
This is considered good news for some and not so good news for others. Regardless of which side of the fence you’re on, here are a few things to keep in mind:
First, this is just an announcement of intentions at this stage. The proposed rule isn’t expected to be published until this Fall, with finalization anticipated in the Spring of 2026. Keep in mind, there are still ongoing court challenges to the limits on PFOA and PFOS. The outcome or progress of these cases could slow things down. On the other side of the table, there will be groups arguing to keep all MCLs in place. EPA rulemaking is rarely a smooth path with everyone in complete agreement.
From a scientist’s point of view, I’m hopeful that dropping the limits for the four additional PFAS will not have as much of an impact on water systems or public health as some headlines suggest. According to the latest summary of data from UCMR 5 (see below), PFOA and PFOS are far more commonly detected than any of the other four PFAS. While the EPA proposal extends deadlines for these two PFAS, the limits remain the same. Furthermore, depending on the type of treatment system chosen, addressing PFOA and PFOS may also address other PFAS – HFPO-DA, PFHxS, PFNA and PFBS as well as other PFAS that were not included in the initial rule.
The three most commonly used treatment technologies include Granular Activated Carbon (GAC), Reverse Osmosis, and Ion Exchange. The additional two years to comply give water systems more time to evaluate which solution best addresses their unique situation. The reason given for the extension was to allow the EPA time to reach out to water systems, especially in rural and small communities, to help them address their compliance challenges. Cost is surely a critical challenge for many, but as we discussed in a recent webinar, there is no one-size-fits-all solution for treating PFAS in drinking water. Source water and water characteristics can be a significant factor in determining the most effective solution.
Watch: Navigating PFAS in Drinking Water: Treatability Insights and Analytical Overview
At the end of the day, EPA announcements make great headlines, but the details matter. While we’re not legal experts, we’re often asked by clients for a more technical perspective on what these rules may mean for them. It’s an element that is missing from much of the media coverage.
If you’d like to discuss PFAS treatability study options for drinking water, reach out to us. The Pace® PFAS Treatability Studies Center of Excellence supports water systems and water treatment professionals as they seek to determine the most effective and economical removal technology for their system. To learn more, visit our website.
