Illinois Statewide Rule

Illinois Soil and Water Conservation Erosion Standards

Heavy RestrictionsApplies statewide across Illinois (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

Last verified: August 20, 2026Source: Illinois General Assembly

Summary

Illinois law authorizes Soil and Water Conservation Districts to establish erosion control standards while NPDES rules require erosion controls at construction sites of one acre or more.

Sec. 39. Compliance with standards - cost sharing. Any person engaging in any land disturbing activity shall be encouraged to comply with the standards for erosion and sediment control established by the district, except those land disturbing activities relating to surface mining permitted under Chapter 4 of the Illinois Pollution Control Board regulations. When proposed land disturbing activities are to be performed on State land or by or on behalf of a State agency, the person engaging in the activities may elect to comply with standards established by the Department.

Source: Illinois General AssemblyView official code

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.

Sources

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