Indiana Construction Stormwater General Permit (CSGP)

The Environmental Protection Agency (EPA) approved the Indiana Construction Stormwater General Permit (CSGP) and became effective on December 18, 2021. This transitions the permit by Rule, as administered through Indiana Administrative Code, to a Master General Permit process. IDEM will be required to seek EPA approval every five (5) years.

How does this affect Indiana communities? 

  • Any project that disturbs more than one (1) acre of total land area or smaller than one (1) acre but is part of a larger plan area must obtain permit coverage under the CSGP.

Changes to the performance and design standards:

  • Existing natural buffers adjacent to the state’s waters must be preserved to promote infiltration and provide protection of the water resources, unless unfeasible.
  • Stormwater quality measures as identified in the Indiana Stormwater Quality Manual (currently in draft format). These include Temporary Sediment Basins, Concrete and Cementitious Washwater Management, Pump Filter Bags, etc.

What is the process to comply with the Construction Stormwater General Permit?

Site-specific stormwater pollution prevention plans must be developed and submitted to the local plan review authority (SWCDs or MS4 Community). The plans are reviewed by the local authority and are deemed sufficient, or the applicant is directed to submit a Notice of Intent (NOI). A Notice of Intent is submitted to IDEM, and construction activities can commence within 48 hours following the submittal of the NOI, provided that the notifications of activities are given. Projects must comply with the plan, and upon project completion, the owner must submit a Notice of Termination. The permittee must retain records and information for a minimum of (3) years.

For additional questions, please contact Drew Flamion, PE,