Where NSF PFAS Testing Standards Stand Today
NSF International’s testing protocols for PFAS removal in drinking water treatment products are built primarily around NSF/ANSI 53, which covers health effects reduction, and NSF/ANSI 58, which covers reverse osmosis systems. Both standards have historically focused on PFOA and PFOS as the primary PFAS test compounds, reflecting the regulatory prominence of those compounds under EPA’s earlier health advisory framework.
The 2024 EPA MCL rule has created a clear mismatch between current NSF testing protocols and the regulatory requirements utilities must now meet. A product certified under NSF 53 for PFOA/PFOS reduction may provide no assurance whatsoever about its performance for PFHxS, PFNA, PFBS, PFHxA, or GenX — the other compounds covered by the MCL rule. This gap has not gone unnoticed by utilities, regulators, or NSF itself.
Industry Signals: What NSF and WQA Are Working On
NSF International and the Water Quality Association (WQA) — the two primary certification bodies for point-of-use and point-of-entry water treatment products in the U.S. — have both signaled that their PFAS testing protocols are under active review. NSF has published preliminary consultation documents indicating that expanded PFAS compound testing requirements are being developed for both NSF 53 and NSF 58, with a focus on adding the MCL compound set as the minimum required test compounds.
The direction of those proposals, based on public consultation inputs and industry working group discussions, is toward requiring manufacturers to test against a defined PFAS compound panel that includes at minimum the six MCL compounds — PFOA, PFOS, PFNA, PFHxS, PFBS, PFHxA — as well as GenX (HFPO-DA). Products would need to demonstrate removal to specified performance thresholds for all compounds in the panel, not just PFOA and PFOS, to carry the certification claim.
This is a significant expansion of the testing burden for manufacturers. Short-chain PFAS compounds are analytically more challenging to work with at low concentrations, require specialized laboratory capability, and may behave differently across different filter media — meaning that products that perform well for PFOA/PFOS may not achieve the same removal levels for the full panel.
Draft Proposal Elements: What to Expect
While final protocols have not been published, several elements of the draft proposals that have circulated in industry consultations are worth noting. First, challenge water specifications are expected to be updated to reflect concentrations more relevant to current regulatory thresholds — potentially at lower spiking levels than historical NSF 53 protocols, which were developed when the regulatory context was parts-per-billion health advisories rather than parts-per-trillion MCLs. This shift in challenge concentration requires more sensitive analytical methods and more precisely controlled test conditions.
Second, there is active discussion about whether certification should be compound-specific — listing each covered compound individually — rather than a blanket “PFAS reduction” claim. Compound-specific certification would allow consumers and utilities to understand exactly which compounds a certified product addresses, rather than assuming broad coverage from a general certification claim. This approach would align NSF certification language more closely with how utilities are now writing procurement specifications.
Third, some draft proposals include provisions for periodic re-certification as the PFAS regulatory list expands — a mechanism that would keep certified products current with an evolving compound list rather than locking in coverage at the point of initial certification.
Implications for Product Manufacturers and Suppliers
For manufacturers of filter media and point-of-use treatment products, the coming expansion of NSF PFAS testing protocols represents both a compliance challenge and a competitive opportunity. Products that are already generating compound-specific performance data — including for short-chain compounds — will be better positioned to meet expanded certification requirements when they are finalized. Manufacturers who have not yet invested in short-chain PFAS testing may face significant lead time to bring products into compliance with new protocols.
The timing of final protocol publication is uncertain — NSF standard-setting processes are consensus-based and can extend over multiple years — but the direction of travel is clear. Manufacturers who are waiting for final protocols before investing in short-chain performance testing are likely making a strategic error. The regulatory pressure driving protocol expansion is real and accelerating, and the facilities capable of conducting the required testing are already capacity-constrained.
The Regulatory-Certification Feedback Loop
The relationship between EPA regulatory standards and NSF certification protocols operates as a feedback loop that tends to tighten over time. As EPA sets more stringent standards and covers more compounds, utilities write procurement specifications that reference certification for those compounds, which creates market pressure for NSF to develop protocols that cover them, which in turn makes product certification for those compounds a competitive necessity. The 2024 MCL rule has strongly activated this feedback loop for short-chain PFAS, and suppliers who understand this dynamic will be better prepared for where the market is heading.