Who needs a SWPPP in Michigan?
Any construction project that disturbs one acre or more — or is part of a larger common plan of development reaching one acre — needs a SWPPP under Michigan permit R 323.2190.
Michigan runs its own delegated stormwater program. Operators obtain coverage from EGLE under Michigan Construction Stormwater Permit-by-Rule (R 323.2190), not directly from the EPA. A small subdivision, a solar pad, and a road-widening project all clear the same one-acre line.
Michigan adds requirements worth flagging early: Part 91 Soil Erosion and Sedimentation Control permit from the local enforcing agency; Sites disturbing 5 or more acres file a Notice of Coverage with EGLE ($400 fee); 1-5 acres are covered automatically once the Part 91 permit is issued; Keep inspection and corrective-action logs for 3 years.
What the plan must contain
A Michigan SWPPPis the site's compliance binder — the document an inspector opens first. It documents:
- 1Site & project descriptionTotal and disturbed acreage, soils, slopes, and the sequence of construction.
- 2Receiving waters & discharge pointsWhere stormwater leaves the site and the waterbodies it reaches.
- 3Erosion & sediment control BMPsSilt fence, stabilized entrances, inlet protection, and stabilization measures.
- 4Inspection schedule & recordsDated, signed inspection logs and the corrective actions taken.
- 5Operator certificationThe SWPPP is signed by the legally responsible party before work begins.
Required and conditional BMPs
| Best management practice | Category | Status |
|---|---|---|
| Perimeter silt fence / sediment barrier | Sediment control | Required |
| Stabilized construction entrance | Tracking control | Required |
| Storm drain inlet protection | Sediment control | Required |
| Soil stabilization (seeding, mulch, blankets) | Erosion control | Required |
| Concrete washout containment | Good housekeeping | Required |
| Sediment basin or trap | Sediment control | Conditional |
| Dewatering / turbidity controls | Pollution prevention | Conditional |
Filing your Notice of Intent
Obtain the local Part 91 SESC permit; for 5 or more acres, submit the Notice of Coverage to EGLE.
A Notice of Termination closes coverage once the site reaches final stabilization. Keeping the SWPPP and its inspection records on site is what keeps a project clear of stop-work orders.
Inspection requirements
Inspect at least once every calendar week and within 24 hours after every precipitation event that results in a discharge from the site (Mich. Admin. Code R 323.2190(2)(e)). Every inspection is dated and signed, and any failed control is corrected before the next storm.
| Trigger | Requirement |
|---|---|
| Routine | At least once every calendar week and within 24 hours after every precipitation event that results in a discharge from the site |
How Michigan differs from the federal permit
| Michigan | Federal (EPA) | |
|---|---|---|
| Authority | EGLE | U.S. EPA |
| Permit | R 323.2190 | EPA CGP |
| Disturbance threshold | 1 acre | 1 acre |
| Plan name | SWPPP | SWPPP |
Because Michigan administers its own program, the federal EPA Construction General Permit does not apply directly here — the state permit governs. Sites inside a regulated municipal storm sewer system may carry additional local ordinance requirements on top of the state permit.
Frequently asked questions
Does Michigan require an engineer to prepare the SWPPP?+–
No. Michigan does not require a licensed PE stamp on a construction SWPPP statewide. The operator certifies the plan; engineer review is optional for complex sites.
What is the disturbance threshold in Michigan?+–
One acre — including sites under an acre that are part of a larger common plan of development totaling one acre or more.
How often must inspections happen in Michigan?+–
Inspect at least once every calendar week and within 24 hours after every precipitation event that results in a discharge from the site (Mich. Admin. Code R 323.2190(2)(e)).
What is a Certified Storm Water Operator and does my site need one?+–
Soil erosion controls must be under the supervision of an EGLE-certified construction storm water operator, whose name and certification number go on the Notice of Coverage.
Michigan-ready in minutes
Siltworks fills in your site data automatically, applies the Michigan requirements, and hands you an inspection-ready SWPPP — at 70–90% less than a consultant.
Requirements summarized from the publicly available Michigan Construction Stormwater Permit-by-Rule (R 323.2190) for planning purposes. The operator must review and certify every SWPPP before use.