Springfield, IL

Illinois Land-Disturbance Threshold

Explain the one-acre/common-plan construction stormwater threshold without turning it into a sub-acre exemption.

Project step 01 · State Threshold Check

Illinois construction stormwater checkpoint

Illinois EPA describes coverage at one acre or more, including a larger common plan; clearing, grading and excavation are land disturbance.

Officially sourcedFor construction-related clearing, check Illinois EPA when disturbance reaches one acre or is part of a larger common plan; smaller work can still have other requirements.

  • Is the purpose construction or development rather than forestry management?
  • Will clearing, grading or excavation disturb at least one acre?
  • Is this segment part of a larger common plan whose total reaches one acre?
  • What other local, wetland, floodplain or environmental rules apply below the threshold?
  • How and when will disturbed soil be stabilized?
  • IEPA coverage check indicated
  • Below cited acreage but other review still required
  • Purpose/classification unresolved

The result is not a permit or exemption determination.

Official sources and scope notes
Primary-source desk

Check the rule at its source

These links support the scoped local notes on this page. They do not approve a particular project.

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