Illinois Erosion Control Law: Statewide Environmental Rules Rules (2026)

Key Facts

SWCD Act: 70 ILCS 405/
NPDES trigger: 1+ acre disturbed
Stabilization: Within 14 days inactive
BMPs required: Silt fence, sediment basins
Plan: Erosion and sediment control

Full Breakdown

The Soil and Water Conservation Districts Act (70 ILCS 405/) creates districts that develop standards for soil loss and erosion. Combined with NPDES ILR10 permits under 35 Ill. Adm. Code 309, any construction disturbing one acre or more must implement best management practices including silt fence, sediment basins, and stabilization within 14 days of inactivity. Local governments may adopt stricter rules, but the statewide one-acre NPDES threshold and SWCD soil-loss standards apply universally.

Violations & Penalties

Failure to install silt fences, allowing sediment offsite, not stabilizing disturbed areas within 14 days, or operating without an ILR10 permit on qualifying sites.

Frequently Asked Questions

When does Illinois require erosion control on construction sites?

Any project disturbing one or more acres triggers an ILR10 NPDES permit requiring an erosion and sediment control plan with best management practices like silt fence and sediment basins.

How quickly must disturbed soil be stabilized in Illinois?

Under the ILR10 general permit, disturbed areas left inactive for 14 or more days must be temporarily or permanently stabilized using mulch, seeding, sod, or other approved cover.

What is a Soil and Water Conservation District?

A local subdivision under 70 ILCS 405 that provides technical assistance, conservation planning, and may set standards for soil loss limits within its boundaries to control erosion.

Illinois Soil and Water Conservation Erosion Standards

Key Facts

Full Breakdown

Violations & Penalties

Frequently Asked Questions

Sources

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