PFAS Compliance Hurdles Remain

Abstract

Having recently passed the one-year mark since the US Environmental Protection Agency (EPA) finalized its National Primary Drinking Water Regulation (NPDWR) for per- and polyfluoroalkyl substances (PFAS), water systems are already progressing toward rule compliance. The PFAS NPDWR, promulgated on April 26, 2024, set maximum contaminant levels (MCLs) for five individual PFAS, requiring systems to monitor for PFAS and take steps to ensure PFAS levels do not exceed these MCLs. EPA also promulgated a Hazard Index MCL, for mixtures of two or more of four PFAS.

Initial monitoring must begin. Groundwater systems serving 10,000 or fewer must collect two samples in a consecutive 12-month period, five to seven months apart. Groundwater systems serving greater than 10,000 and all surface water systems must collect four samples in a consecutive 12-month period, two to four months apart. Data must be collected on or after Jan. 1, 2019.

Systems can use previously collected data to satisfy initial monitoring requirements. In November 2024, EPA issued a memorandum providing additional guidance on how primacy agencies may evaluate previously collected PFAS monitoring data from the fifth Unregulated Contaminant Monitoring Rule or state monitoring efforts to satisfy initial monitoring requirements.

Additionally, the rule requires that data be collected and analyzed using EPA Method 533 or Method 537.1, Version 2.0. In January 2025, EPA announced expedited approval of EPA Method 537.1, Version 1.0, for initial monitoring under the PFAS NPDWR. This approval may help systems address the timing gap between Jan. 1, 2019, and when other approved analytical methods became available (i.e., December 2019 for Method 533 and March 2020 for Method 537.1, Version 2.0).

EPA prepared a series of plain English summaries of key rule elements, including Control of PFAS Overview: A Quick Reference Guide, Fact Sheet: PFAS NPDWR Monitoring and Reporting, PFAS Hazard Index: A Quick Reference Guide, and PFAS NPDWR Significant Figures and Rounding Requirements. These guides supplement rule text incorporated into the Code of Federal Regulations, summarizing and expanding on important facets of the rule.

In February 2025, AWWA released standard ANSI/AWWA B104-24, Single-Use Ion Exchange Treatment for Trace Contaminant Removal. B104-24 complements the existing standard ANSI/AWWA B604-18, Granular Activated Carbon. In April 2025 AWWA in collaboration with of the Association of State Drinking Water Administrators, released PFAS Treatment Evaluation: Framework for Approaching Permit/Plan Approval. This framework serves as a resource for water system managers and primacy agency staff to evaluate PFAS treatment selection options, facilitating expeditious treatment system approval.

As systems look toward implementing a new rule amid an ongoing political transition, uncertainty abounds. The announcement emphasized a continued focus on removing PFOA and PFOS, so the number of systems triggered into treatment will be little affected by anticipated rule changes. EPA's proposed changes offer systems another two years to make necessary improvements but the rulemaking will not be finalized until mid-2026. Many hurdles to achieving compliance remain.