The United States Environmental Protection Agency (US EPA) is revising the National Pollutant Discharge Elimination System (NPDES) Multi-Sector General Permit (MSGP) for Stormwater Discharges Associated with Industrial Activity. The current permit expires on February 28, 2026. This article highlights the major changes most likely to impact operators, cutting through the regulatory language to focus on what matters operationally, financially, and strategically.
What’s Changing with the MSGP—and What It Means for Your Facility
The Multi-Sector General Permit (MSGP) has long been the backbone of industrial stormwater compliance across the United States. But as regulatory expectations evolve—driven by water quality concerns, climate impacts, and enhanced enforcement—the MSGP is changing too.
With upcoming federal updates to the MSGP and a wave of state-level revisions, industrial operators should expect increased monitoring requirements, greater documentation expectations, and increased scrutiny from regulators.
Federal MSGP Updates: Raising Compliance Bar
The upcoming federal MSGP reflects EPA’s broader push toward accountability, transparency, and measurable environmental outcomes. Key themes expected in the new permit include:
- Higher Stormwater Control Expectations
- Increased emphasis on evaluating stormwater control resilience in areas prone to major storm events and floods.
- Expanded Monitoring Requirements
- Add PFAS indicator monitoring for applicable sectors
- Expand benchmark monitoring requirements
- Revise benchmark monitoring frequencies
- Increase monitoring and response obligations for discharging to impaired waters
- Increased Transparency
- Stormwater Pollution Prevention Plans (SWPPPs) must be made publicly available in full, either as a standalone document or via public webpage.
- Facilities must post on-site signage identifying MSGP coverage, receiving waters, and how the public can access the SWPPP or report concerns.
State Permit Changes: Local Details Matter
While EPA administers the federal MSGP in most states, other states implement their own industrial stormwater programs which can be more stringent than the federal baseline. Key state-level themes expected in the expiring permits include:
- Michigan (effective April 1, 2026)
- Enhance SWPPP requirements, including documentation and implementation activities
- Increased emphasis on certified industrial stormwater operators
Note: Michigan has not publicly adopted the EPA’s proposed PFAS indicator monitoring but has proactively developed PFAS-related guidance for facilities to follow when PFAS are present in stormwater.
- Texas (effective August 14, 2026)
- Allowance for firefighting water discharges under defined conditions
- Expanded NetDMR reporting requirements for electronic data submissions
- Acceptance of electronic Stormwater Pollution Prevention Plans (SWP3s)
- New Benchmark Monitoring requirements for certain industrial sectors
Note: As of the latest publicly available draft, PFAS monitoring is not explicitly added as a required monitoring parameter under the Texas MSGP.
New State Program: Ohio Introduces a New Industrial Stormwater General Permit (GP)
With the growing number of data centers around the country to accommodate the demand for cloud computing, artificial intelligence and other online services, Ohio is introducing a new industrial stormwater general permit. Administered by the Ohio Environmental Protection Agency, the new permit will authorize stormwater and wastewater discharges from the state’s growing number of data center facilities.
- Ohio (Effective Date: TBD)
- Proposed wastewater discharges include:
- Non-contact cooling waters (once through or re-circulated water that does not come into contact with the process operations of a facility and is used only to convey heat from the facility)
- Low volume wastewaters (such as, cooling tower blowdown, boiler blowdown, and air compressor condensate yet excludes some waste streams like sanitary wastes) and
- Stormwater associated with the industrial activities from the site.
- Key parameters limited in this permit are: pH, Total Filterable Residue (aka Total Dissolved Solids), Residual Chlorine and Residual Oxidants.
- Key parameters monitored in this permit are: Flow volume, Oil and Grease, and Temperature.
- Proposed wastewater discharges include:
What Facilities Should Be Doing Now
Although the 2026 MSGP and Ohio GP are not yet final, the direction is clear. Facilities should begin preparing by:
- Reviewing stormwater programs at existing data centers and identify areas that may require updates under Ohio’s new permit framework
- Reviewing sector applicability for PFAS monitoring
- Evaluating historical benchmark data and identifying recurring exceedances
- Assessing discharge locations for impaired waters
- Updating SWPPPs to ensure they are accurate, complete, and inspection-ready
- Identify stormwater controls that require repair maintenance and schedule corrective actions
- Budgeting for new 2026 SWPPP development and a supporting site visit
- Budgeting for increased sampling, laboratory costs, and corrective actions
Early preparation can significantly reduce compliance risk and avoid reactive—and costly—responses once the permit is finalized. Facilities should assess state-level permit updates and guidance documents to determine how new, or revised requirements apply at their specific location.
How EDGE Engineering & Science Can Help
- MSGP applicability and coverage evaluations
- SWPPP development, updates, inspections and audits
- Stormwater control design and optimization
- Erosion and sedimentation evaluation
- Benchmark and compliance monitoring support
- Corrective action planning, prioritizing, and documentation
- Regulatory interpretation for federal and state permits
- Agency liaison for local, state, and federal inquires and coordination
- Inspection readiness and enforcement response support
If you would like assistance preparing for the new MSGP requirements, we are here to help!