PFAS Monitoring in Industrial Stormwater: Key Updates from EPA’s Proposed 2026 MSGP

The United States Environmental Protection Agency (EPA) is taking a first step towards requiring PFAS sampling of certain industrial stormwater discharges. On December 13, 2024, U.S. EPA published a notice requesting public comment for the 2026 National Pollutant Discharge Elimination System (NPDES) general permit for stormwater discharges associated with industrial activity, also referred to as the 2026 Multi-Sector General Permit (MSGP). See 89 Fed. Reg. 101000 (EPA Public Comment Request on MSGP) When final, the new MSGP general permit replaces the existing one that expires on February 28, 2026.  The proposed general permit includes a requirement for certain industrial sectors (23 of the 30 industrial sectors; the excluded sectors are listed below)  to conduct quarterly “report-only” indicator sampling and analytical monitoring for 40 different compounds with PFAS substances. EPA also has requested comment on whether all 30 of the industrial sectors should be included and on whether they should be subject to PFAS-related benchmark monitoring, which could trigger inspection and corrective action obligations under the MSGP.  EPA also requests comment on considering the recently published aquatic life criteria for PFOA and PFOS, as well as the Clean Water Act Aquatic Life Benchmarks for PFAS (89 Fed. Reg. 81077), as benchmark monitoring threshold(s). The EPA’s MSGP is only applicable in those few states where U.S. EPA is the NPDES permitting authority (right now this is Massachusetts, New Hampshire, New Mexico for stormwater discharges) But many states model their NPDES stormwater general permits after the MSGP, and hence it is likely that similar requirements are expected to be adopted for state permits, particularly in those states (e.g., Michigan) that have been aggressively pursuing PFAS regulation. Comments must be received on or before February 11, 2025.

List of 7 Excluded Industrial Sectors:

Sector E—Glass, Clay, Cement, Concrete, and Gypsum Product Manufacturing.

Sector G—Metal Mining (Ore Mining and Dressing).

Sector H—Coal Mines and Coal Mining-Related Facilities.

Sector J—Mineral Mining and Dressing.

Sector O—Steam Electric Generating Facilities.

Sector Q—Water Transportation.

Sector AD—Reserved for Facilities Not Covered Under Other Sectors and Designated by the Director.