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EPA Invites Comment on Proposed 2026 Multi-Sector General Permit (MSGP) for Stormwater Associated with Industrial Activities that Includes Requirements for PFAS Monitoring
On December 13, 2024, the U.S. EPA published in the Federal Register its proposed 2026 Multi-Sector General Permit for Stormwater Discharges Associated with Industrial Activity (2026 MSGP) and is soliciting public comments through February 11, 2025. Once finalized, the 2026 MSGP is targeted to replace the existing 2021 MSGP (by February 28, 2026) and would cover stormwater discharges from industrial facilities in areas where EPA is the NPDES permitting authority. Importantly, the 2026 MSGP will likely serve as a guide for other NPDES permitting authorities in developing their own industrial stormwater permitting programs as it has in prior years. The proposed 2026 MSGP contains, among other things, a number of notable updates, including: (i) quarterly stormwater indicator monitoring for per- and polyfluoroalkyl substances (PFAS) for numerous industrial sectors; (ii) new benchmark monitoring for pH, Total Suspended Solids (TSS), Chemical Oxygen Demand (COD), ammonia, nitrate, nitrite, and metals for various industrial sectors; (iii) changes to the benchmark monitoring schedule; and (iv) new monitoring and response measures for pollutants causing impaired waters.
With respect to PFAS indicator monitoring, quarterly sampling requirements would apply to all operators in over 20 different industrial sectors, including those which may not traditionally be thought of with respect to PFAS, such as Land Transportation and Warehousing. Importantly, EPA is proposing that PFAS indicator monitoring apply to all 40 PFAS compounds listed in EPA’s newly updated Method 1633A (December 2024). EPA’s Fact Sheet explains that the PFAS indicator monitoring is a “report-only” requirement, does not have a benchmark threshold or baseline value for comparison, nor does it require follow-up corrective actions if PFAS is detected in stormwater effluent. EPA states that the PFAS data is being collected to provide EPA and facility operators with a baseline understanding of PFAS in stormwater and may be used by EPA to inform future consideration of potential PFAS benchmark monitoring for sectors with the potential to discharge PFAS in stormwater. EPA’s proposal to require quarterly sampling for 40 PFAS compounds by all listed sectors will likely warrant comment from potentially impacted industrial sectors.
If you are interested in understanding how the 2026 MSGP may impact your industrial operations or would like assistance in submitting comments on the proposed 2026 MSGP, please contact Brenda Gotanda or Technical Consultants Will Hitchcock or Mike Nines of our firm.
