CGP vs. MSGP: Which Stormwater Permit Does Your Project Need?
CGP (Construction General Permit) covers construction sites disturbing soil. MSGP (Multi-Sector General Permit) covers industrial facilities with stormwater exposure. They are different permits, different forms, different agencies, and different SWPPP requirements. Many facilities need both simultaneously.
10-Dimension Permit Comparison
| Dimension | CGP — NMR100000 | MSGP 2021 |
|---|---|---|
| Who it covers | Construction operators disturbing 1+ acres | Industrial facilities in 11 sectors with stormwater exposure |
| Permit trigger | 1-acre soil disturbance (or Common Plan of Development) | Industrial activity + stormwater exposure from industrial materials/equipment |
| SWPPP type | Construction SWPPP — temporary, project-duration | Industrial SWPPP — permanent, annual-update |
| Inspection frequency | Every 14 days + within 24 hrs of ≥ 0.25" storm event | Quarterly (every 90 days) + within 24 hrs of ≥ 0.25" storm event |
| NOI/NOT process | Required via EPA NeT / NMPDES eDMR (transition); NOT at final stabilization | Required via EPA NeT; NOR (Notice of No Exposure) option for covered storage |
| Current status | Active — NMR100000 expires Feb 16, 2027 | MSGP 2021 expired Feb 28, 2026 — administrative continuance active |
| Administering agency | EPA / NMED (transitioning to NMPDES state authority in 2026) | EPA (federal — no state transition planned for MSGP) |
| Certifications | QISM, CPESC, CESSWI recommended for qualified inspector | No specific national certification required; Pollution Prevention Team required |
| Benchmark monitoring | Not required under standard CGP | Required — sector-specific benchmarks; exceedances trigger corrective action |
| Penalties (CWA) | Up to $68,445 per day per violation | Up to $68,445 per day per violation |
Permit Decision Tree
Work through these questions in order to determine your permit requirements:
Uncertainty = request a permit determination. Inspections Plus provides written permit applicability determinations for projects where the answer is not clear-cut. This is billable work, and worth every dollar compared to a Clean Water Act enforcement action.
Related Resources
Dual Permit Compliance — When You Need Both
Dual-permit projects are operationally complex. The CGP SWPPP and MSGP SWPPP are separate documents with separate inspection schedules. Inspection Plus coordinates these documents so they cross-reference each other, use consistent site maps, and satisfy both permit frameworks with a single mobilization wherever possible.
What Stays Separate
- NOI filings — two separate NOIs in EPA NeT
- SWPPP documents — two binders, different templates
- Permit numbers — one construction, one industrial
- DMR reporting — MSGP only, not CGP
What Can Be Coordinated
- Site map — one master map referenced in both
- Inspection scheduling — combined visits where possible
- BMP installation — shared infrastructure where appropriate
- Records retention — consolidated filing system
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