Industrial Sites and Stormwater

General Permits No. 1 & 3

General Permit No. 1 is for stormwater discharge associated with industrial activity from businesses primarily engaged in manufacturing, trucking and transportation, construction and mining. General Permit No. 3 is for stormwater discharge associated with industrial activity from asphalt plants, concrete batch plants, rock crushing plants, and construction sand and gravel facilities. Industrial activity is regulated as part of the National Pollutant Discharge Elimination System (NPDES) administered by the Environmental Protection Agency (EPA).

A Stormwater Pollution Prevention Plan (SWPPP) must be developed for each site covered under General Permit No. 1 and No. 3. According to the Iowa DNR, the plan must (1) identify the potential sources of pollution that could alter the quality of stormwater discharge and describe implementation of practices that will be used to reduce pollutants from discharge. SWPPPs should be designed for consistency among other plans specific to your industrial operation. Summary guidance and the permit language for both General Permit No. 1 and No. 3 can be found here.

Industrial operations should also be aware of special requirements that may impact their stormwater discharge, such as discharging through Municipal Separate Storm Sewer Systems (MS4s).

Additional Guidance

The National Academies of Science, Engineering, and Medicine has produced a handy guide for stormwater permitting and builds upon a 2009 National Research Council publication by adding information regarding monitoring and management. The PDF can be downloaded here.

The Iowa Stormwater Education Partnership held a special training for industrial stormwater permitting for the first time in 2018. Additional training opportunities will be offered in 2020. Check the Events Calendar for upcoming events.