CGP vs. MSGP: Which SWPPP Permit Does Your Project Need?
SWPPP HUB Editorial
3/24/2026
Quick Answer: The CGP (Construction General Permit) covers temporary land-disturbing construction activity and expires when you file your Notice of Termination. The MSGP (Multi-Sector General Permit) covers permanent industrial stormwater discharges from ongoing facility operations and renews every five years. A construction project at an industrial facility can require both simultaneously.
Two Permits, Two Completely Different Compliance Worlds
If you work in construction, environmental compliance, or industrial operations and have encountered both acronyms — CGP and MSGP — without a clear sense of which applies to you, this guide will resolve that.
The Construction General Permit (CGP) and the Multi-Sector General Permit (MSGP) are both NPDES stormwater permits requiring a Stormwater Pollution Prevention Plan (SWPPP). But they operate under different legal frameworks, cover different activities, have different inspection and monitoring requirements, and follow different lifecycles. Treating one as a substitute for the other — or assuming one satisfies both — is a compliance failure with real enforcement exposure.
The Construction General Permit (CGP)
What It Covers
The CGP governs stormwater discharges associated with construction activity — specifically, land-disturbing activities such as clearing, grading, excavation, and demolition. The federal CGP is issued by EPA; in states with delegated NPDES authority (including New Mexico via NMPDES, Arizona via AZPDES, and Texas via TPDES), the state-equivalent CGP governs instead.
Trigger: Land disturbance of 1 acre or more, OR any disturbance that is part of a larger common plan of development that will ultimately disturb 1+ acres.
Duration: The CGP is temporary. It begins when your NOI is accepted and coverage is granted, and it ends when you file a Notice of Termination (NOT) upon achieving final stabilization. A CGP permit has no fixed term — it runs as long as your project is active.
Who uses it: General contractors, developers, homebuilders, subcontractors performing significant earthwork, project owners.
CGP SWPPP Requirements
A CGP SWPPP is focused on construction-phase pollution prevention:
- Site description including acreage of disturbance and receiving waters
- Identification of all pollutant sources (disturbed soil, stockpiles, washout areas, fueling areas)
- Best Management Practices (BMPs) for erosion control and sediment control
- Scaled site map showing BMP locations and drainage patterns
- Inspection and maintenance schedule
- Corrective action procedures
- Subcontractor training documentation
CGP Inspection Requirements
- Routine: At least every 14 calendar days throughout active construction
- Post-storm: Within 24 hours of a qualifying precipitation event
- Inspector credential: Varies by state — no federal requirement, but New Mexico's proposed June 2026 rule may require ESI or CPESC credentials for Tier 2 and Tier 3 sites
- Documentation: Every inspection documented in writing; records maintained on-site
CGP Termination
When construction is complete and all disturbed areas have achieved final stabilization, file a Notice of Termination (NOT) through the applicable permit authority. Filing the NOT closes out your coverage and ends your inspection obligations. Failure to file the NOT is a common violation — it leaves your coverage active and your inspection obligations ongoing after the project is physically complete.
The Multi-Sector General Permit (MSGP)
What It Covers
The MSGP governs stormwater discharges from industrial facilities — manufacturing plants, mining operations, recycling yards, vehicle maintenance facilities, power generation facilities, and dozens of other industrial categories. Where the CGP is temporary and construction-focused, the MSGP is permanent and facility-focused.
The federal MSGP is issued directly by EPA and covers industrial facilities in states that have not received EPA delegation for the industrial stormwater program. Unlike the construction program, where most states operate their own delegated permits, many states rely on the federal MSGP for industrial stormwater regulation.
Current status: The 2021 EPA MSGP expired February 28, 2026 and is operating under administrative continuance. All compliance obligations under the 2021 permit remain fully in effect.
Trigger: An industrial facility discharging stormwater that falls under one of the MSGP's 29 industrial sectors — ranging from Sector A (Timber Products) through Sector AD (Electronic and Electrical Equipment). See 40 CFR Part 122 Appendix B for the full sector list.
Duration: The MSGP has a 5-year permit term. Unlike the CGP, there is no termination upon completion of activity — the permit renews as long as the facility operates and triggers permit coverage.
Who uses it: Plant managers, EHS directors, facility operators, industrial property owners.
MSGP SWPPP Requirements
An MSGP SWPPP is focused on permanent industrial pollution prevention:
- Facility description including all areas of industrial activity exposed to stormwater
- Site map showing all exposure areas, stormwater conveyances, and discharge points
- Identification of all potential pollutant sources by industrial activity type (material storage, process areas, loading/unloading, vehicle maintenance, etc.)
- Sector-specific BMPs addressing the pollutants associated with your industrial category
- Spill prevention and response procedures
- Employee training program
- Annual SWPPP review and recertification — required every year, even if no changes are made
MSGP Inspection Requirements
MSGP inspections are structurally different from CGP inspections:
- Quarterly visual observations: At least once per quarter, during an active discharge event, observe each stormwater discharge point. Document the discharge's appearance, color, odor, and any visible pollutants. This is not a full site inspection — it is a targeted observation of what is leaving the site during a storm.
- Annual comprehensive site compliance evaluation: A thorough assessment of the entire facility, all BMPs, all exposure areas, and the current SWPPP. Must be conducted by a qualified individual (typically an environmental professional). This is the MSGP equivalent of the CGP's routine inspection but occurs annually rather than every 14 days.
- All inspections documented with date, time, inspector name, discharge conditions, and corrective actions.
MSGP Monitoring Requirements
This is where the MSGP diverges most significantly from the CGP: sector-specific benchmark monitoring. Most MSGP sectors require collection and laboratory analysis of stormwater samples during discharge events, with results compared against EPA-established numeric benchmarks.
- Monitoring frequency: Quarterly during the first four quarters of permit coverage, then semi-annually for the remainder of the permit term
- Benchmark exceedances: Tier 1 (investigate and implement corrective action), Tier 2 (develop and implement a NAL exceedance response action plan)
- Electronic reporting: All Discharge Monitoring Reports (DMRs) submitted electronically via EPA's NeT-MSGP system. Paper reporting is not permitted.
The CGP has no equivalent chemical monitoring requirement. This distinction — visual-only inspections (CGP) vs. laboratory-analyzed stormwater samples (MSGP) — is the most operationally significant difference between the two programs.
MSGP Renewal
The MSGP does not terminate when activity winds down. It renews. When EPA issues a new MSGP (typically every 5 years), covered facilities must submit a new NOI under the new permit within EPA's specified submission window. Missing the renewal window results in lapsed coverage — an unpermitted discharge — until a new NOI is filed and accepted.
Side-by-Side Comparison
| Feature | CGP (Construction) | MSGP (Industrial) | |---|---|---| | Covers | Land-disturbing construction activity | Industrial stormwater discharges | | Trigger | 1+ acres of land disturbance | Industrial facility in a covered sector | | Duration | Temporary (project-based) | Permanent (facility-based, 5-year term) | | SWPPP focus | BMPs for erosion/sediment control | Sector-specific industrial pollutant sources | | Routine inspections | Every 14 calendar days | Quarterly visual observations | | Comprehensive evaluation | Not applicable | Annual | | Stormwater sampling | Not required (visual only) | Sector-specific benchmark monitoring | | Electronic reporting | NOI and NOT via ePASS or equivalent | DMRs via EPA NeT-MSGP | | Termination | File NOT upon final stabilization | Permit renewal every 5 years | | Federal vs. state | Most states have delegated permits | Many states rely on federal MSGP |
When Does a Facility Need Both?
This is the scenario most operators miss: a facility can require both a CGP and an MSGP simultaneously.
Scenario 1: Construction at an Active Industrial Facility
A manufacturing plant undergoing a facility expansion that disturbs 3 acres needs:
- MSGP coverage for the ongoing industrial stormwater discharges from facility operations
- CGP coverage for the construction activity disturbing 3 acres of land
Both SWPPPs must exist and be maintained. The construction SWPPP covers the earthwork; the industrial SWPPP covers the ongoing facility operations. They are separate documents with separate NOIs and separate compliance obligations.
Scenario 2: Construction Project With On-Site Fuel Storage Exceeding the SPCC Threshold
A large construction project with a 1,000-gallon diesel tank plus fuel in equipment sumps and generators may collectively exceed the SPCC (Spill Prevention, Control, and Countermeasure) threshold of 1,320 gallons of aggregate oil storage. In that case:
- CGP for the land disturbance
- SPCC plan for the oil storage (not the MSGP, but a third plan)
Scenario 3: Industrial Facility Undergoing Demolition With Earthwork
A facility being demolished with 2+ acres of earthwork needs CGP coverage for the construction activity. If the facility previously held MSGP coverage for industrial operations and those operations have ceased, the MSGP may be eligible for termination — but not until industrial activity has fully stopped and no further industrial stormwater discharges will occur.
Decision Tree: Which Permit Do You Need?
Step 1: Is your project disturbing 1 acre or more of land (or part of a larger common plan that will)?
- Yes → You need CGP coverage. Proceed to Step 2.
- No → Proceed to Step 2 only.
Step 2: Does your facility or project site involve ongoing industrial operations that discharge stormwater to waters of the U.S.?
- Yes → Determine your MSGP sector. If you fall under a covered sector, you need MSGP coverage.
- No → You may only need the CGP.
Step 3: Did both Step 1 and Step 2 result in "yes"?
- Yes → You need both permits. Maintain two separate SWPPPs. File two NOIs.
- No → Proceed with the applicable single permit.
The Two NOI Processes
Both permits require a Notice of Intent, but the submission process differs:
CGP NOI:
- Submitted to your state permitting authority (NMED via ePASS in NM; ADEQ portal in AZ; TCEQ in TX) or to EPA directly in non-delegated states
- Required before land disturbance begins — in most states, you cannot start until you receive written authorization
- See our complete guide: How Long After Filing Your NOI Can You Start Construction?
MSGP NOI:
- Submitted to EPA via the NPDES Electronic Reporting system
- Coverage typically begins 7 days after NOI submission (in most sectors)
- When a new MSGP is issued, there is a defined submission window — typically 90 days — to file your new NOI under the new permit
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