Who needs a SWP3 in Ohio?
Any construction project that disturbs one acre or more — or is part of a larger common plan of development reaching one acre — needs a SWP3 under Ohio permit OHC000006.
Ohio runs its own delegated stormwater program. Operators obtain coverage from Ohio EPA under Ohio Construction General Permit (OHC000006), not directly from the EPA. A small subdivision, a solar pad, and a road-widening project all clear the same one-acre line.
Ohio adds requirements worth flagging early: Notice of Intent via the Ohio EPA eBusiness Center; Temporary stabilization within 2 days for idle areas within 50 feet of surface water; within 7 days for areas dormant more than 14 days.
What the plan must contain
An Ohio SWP3is 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 SWP3 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
Submit a complete and accurate Notice of Intent application form and the appropriate fee through the Ohio EPA eBusiness Center at least 21 days before construction activity begins (45 days, with the completed SWP3, in the Big Darby Creek watershed and portions of the Olentangy watershed). Coverage is not effective until the applicant receives the approval letter granting coverage from the director of Ohio EPA (OHC000006 Part I.F.1.a).
A Notice of Termination closes coverage once the site reaches final stabilization. Keeping the SWP3 and its inspection records on site is what keeps a project clear of stop-work orders.
Inspection requirements
Inspect at least once every 7 calendar days and by the end of the next calendar day after a storm producing more than 0.5 inch of rain per 24-hour period (the next calendar day excludes weekends and holidays unless work is scheduled) (OHC000006 Part III.G.2.i). Every inspection is dated and signed, and any failed control is corrected before the next storm.
| Trigger | Requirement |
|---|---|
| Routine | At least once every 7 calendar days and by the end of the next calendar day after a storm producing more than 0.5 inch of rain per 24-hour period (the next calendar day excludes weekends and holidays unless work is scheduled) |
How Ohio differs from the federal permit
| Ohio | Federal (EPA) | |
|---|---|---|
| Authority | Ohio EPA | U.S. EPA |
| Permit | OHC000006 | EPA CGP |
| Disturbance threshold | 1 acre | 1 acre |
| Plan name | SWP3 | SWPPP |
Because Ohio 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 Ohio require an engineer to prepare the SWP3?+–
No. Ohio does not require a licensed PE stamp on a construction SWP3 statewide. The operator certifies the plan; engineer review is optional for complex sites.
What is the disturbance threshold in Ohio?+–
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 Ohio?+–
Inspect at least once every 7 calendar days and by the end of the next calendar day after a storm producing more than 0.5 inch of rain per 24-hour period (the next calendar day excludes weekends and holidays unless work is scheduled) (OHC000006 Part III.G.2.i).
Is a SWP3 the same as a SWPPP?+–
Yes. Ohio uses the term "SWP3" for what other states call a SWPPP — the same plan and the same requirements.
Ohio-ready in minutes
Siltworks fills in your site data automatically, applies the Ohio requirements, and hands you an inspection-ready SWP3 — at 70–90% less than a consultant.
Requirements summarized from the publicly available Ohio Construction General Permit (OHC000006) for planning purposes. The operator must review and certify every SWP3 before use.