Why Facilities Should Prepare Now
The U.S. EPA has proposed a new Multisector General Permit (MSGP) for industrial stormwater discharges that will govern the next five-year permit cycle. While the permit is not yet final, it clearly signals where stormwater regulation is heading and why facilities should begin preparing now. The proposed changes make PFAS monitoring a priority for most sectors and will increase monitoring costs, operational oversight and public visibility of stormwater compliance results for many industrial operators.
What’s Changing
The proposed permit includes several notable shifts that could affect industrial facilities:
- Expanded monitoring requirements, including new PFAS indicator monitoring for many industrial sectors
- Increased sampling frequency, particularly early in the permit term
- More prescriptive corrective action timelines following benchmark exceedances
- Greater scrutiny of visible indicators (sheen, foam, discoloration), which are increasingly enforced
Taken together, these changes raise both compliance effort and regulatory exposure, especially since stormwater monitoring data submitted under NPDES permits are publicly accessible.
Sectors With Added PFAS Monitoring Requirements
When Will the New Permit Be Issued
The existing 2021 MSGP expired on February 28, 2026, but will remain in effect until the proposed permit is final. The proposed permit went through public comment in early 2025 and is expected to be finalized this year.
Why This Matters Even If You’re Not Under the Federal MSGP
Many facilities assume these changes apply only to operators covered directly under the federal MSGP. That’s not the case.
States with authorized stormwater programs are required to issue permits that are equal to or more stringent than the federal MSGP. Because of this, facilities regulated under state issued industrial stormwater permits should expect similar requirements to follow over time. In practice, this means most industrial facilities nationwide will be impacted — not just those directly covered under the federal permit.
What Facilities Should Be Doing Now
Even while the current permit remains in effect, this interim period presents an opportunity for industrial operators to reduce future compliance risks by proactively evaluating their programs:
- Assess whether existing best management practices (BMPs) and controls can meet tighter benchmarks
- Review Stormwater Pollution Prevention Plans (SWPPPs) and site maps for accuracy and defensibility
- Evaluate the operational impact of expanded monitoring, sampling and reporting requirements
- Identify data management, tracking and documentation gaps before requirements increase
Waiting until the permit is finalized often means responding under compressed timelines and increased regulatory pressure.
Related Services
How TRC Can Help
TRC helps industrial facilities move beyond reactive stormwater compliance toward proactive and defensible preparation for emerging requirements. Our stormwater services include:
- MSGP and state permit readiness assessments
- SWPPP updates, site mapping and BMP evaluations
- Stormwater monitoring program design and data defensibility support
- Strategic planning for emerging regulatory requirements, including PFAS considerations
Preparing early can help facilities spread compliance costs over time, reduce enforcement and reputational risk and position their operations for smoother transition when new permit conditions take effect.
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