SWPPP Requirements in Illinois

Who needs a SWPPP in Illinois?

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 Illinois permit ILR10.

Illinois runs its own delegated stormwater program. Operators obtain coverage from Illinois Environmental Protection Agency (Illinois EPA), Division of Water Pollution Control under General NPDES Permit for Storm Water Discharges From Construction Site Activities (ILR10), not directly from the EPA. A small subdivision, a solar pad, and a road-widening project all clear the same one-acre line.

Illinois adds requirements worth flagging early: Submit the NOI and an electronic copy of the SWPPP through EPA CDX in time for a 30-day review before construction starts; coverage begins 30 days after Illinois EPA receives them unless the Agency says otherwise (Parts I.C.3, II.A.1, II.C.9, II.D); Send signed copies of the NOI to any local agency that approved sediment and erosion, grading, or storm water management plans, and to the ILR40 MS4 permittee where the site lies in an ILR40 area (Part II.E); Controls must be at least as protective as the Illinois Urban Manual (2017); approved local plan requirements are incorporated by reference (Parts IV.D.2 and IV.D.2.i); Post the coverage letter and the general permit (or other proof of coverage) in a prominent place at the site for public viewing (Part IV.B.5); Every contractor and subcontractor that implements a measure signs the ILR10 certification statement, kept in the SWPPP (Part IV.F); Report any noncompliance to the Illinois EPA Field Operations Section within 24 hours and file an Incidence of Noncompliance (ION) report within 5 days (Part IV.D.4.f); Sites discharging directly to a water 303(d)-listed for suspended solids, turbidity, or siltation design the SWPPP for at least the 25-year, 24-hour storm; discharges to waters with a sediment TMDL must be consistent with its wasteload allocation (Parts IV.D.2.e and III.B); Inspect dewatering discharges once per day while they occur and record the report within 24 hours (Part IV.D.4.c); Store chemical containers of 55 gallons or more at least 50 feet from receiving waters, drainage features, and storm drain inlets, or document why that is infeasible (Part IV.D.2.f.(iii)).

What the plan must contain

An Illinois SWPPPis the site's compliance binder — the document an inspector opens first. It documents:

1. 1Site & project descriptionTotal and disturbed acreage, soils, slopes, and the sequence of construction.
2. 2Receiving waters & discharge pointsWhere stormwater leaves the site and the waterbodies it reaches.
3. 3Erosion & sediment control BMPsSilt fence, stabilized entrances, inlet protection, and stabilization measures.
4. 4Inspection schedule & recordsDated, signed inspection logs and the corrective actions taken.
5. 5Operator certificationThe SWPPP is signed by the legally responsible party before work begins.

Required and conditional BMPs

Filing your Notice of Intent

Submit the Notice of Intent and the SWPPP electronically through EPA’s Central Data Exchange (CDX) with digital signature, then mail the fee with the assigned permit ID to Illinois EPA, Division of Water Pollution Control (Part II.D).

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 7 calendar days and within 24 hours of the end of (or by the end of the following business or work day after) a storm producing 0.5 inch of rain or more (qualified personnel; areas inaccessible because of flooding or other unsafe conditions are inspected within 72 hours of becoming accessible) (ILR10 Part IV.D.4). Every inspection is dated and signed, and any failed control is corrected before the next storm.

How Illinois differs from the federal permit

Because Illinois 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