Industrial stormwater: Permit development and program history


April 1, 2020: New Industrial Stormwater Permit/No Exposure Certification is in effect until April 1, 2025.

General changes

  • Getting the permit into a “Tempo-ready” format: The formatting and overall look of the new permit will be different in order to fit into MPCA’s new Tempo database system. These visual differences can be seen in MPCA’s Construction Stormwater 2013 general permit and 2018 general permit.
  • Changing language to present tense, plain language: As we reformat the permit, we’re changing the language (not the requirements) to reflect active voice/present tense requirements, and trying to make the requirements easier to understand.
  • Corrected four incorrect permit references for monitoring waiver forms

Part I

  • Authorization of discharges: For transferring coverage, remove “prior owner/operator” requirement; just have current owner and operator sign.
  • Clarity of vehicle washing prohibition: Within the limitations on authorization, add examples: 2. Domestic and industrial wastewater and process wastewater. For example, wash water, commercial equipment and/or vehicle cleaning.

Part III

  • Salt storage, salt management: BMPs for salt management: cover/store indoors, direct drainage away from receiving waters, reduce exposure when adding/removing from pile, and document salt pile location within SWPPP. Hired contractors should minimize use of salt.
  • Infiltration for all sectors: Infiltration for all Industrial Sectors:  Prohibits new infiltration devices in areas of predominately Hydrologic Soil Group D (clay) soils, and areas where soil infiltration rates are more than 8.3 inches per hour.  Changed wording from ‘infiltration device’ to ‘infiltration system.
  • BMP maintenance: Reduce time for installing backup BMPs from 7 days to 48 hours

Part IV

  • SWPPP modifications: If there are changes in personnel responsible in for any permit requirement, update SWPPP. Removed 1:24000 facility map scale requirement.
  • Annual reports: Added a new permit chapter Annual Report. No changes were made to the Annual Report requirements.

Part V

  • pH calibration: The Permittee shall maintain written records of all calibrations and maintenance of their pH meter within SWPPP.

Part VII

  • Remove :
    • “Any additional” references within each sector “chapter”
    • Part 2 in each chapter; language is largely redundant to part 1 in each sector chapter.
  • Sectors J & L: A separate CSW permit is not required for certain activities considered part of overall industrial operations for these facilities.
  • Sector J: Dewatering discharges aren’t allowed, remove phrase “dewatering or other process water”
  • Sectors M and N
    • Sector M: Corrected the permit benchmark values listed for Toluene and Ethyl benzene.  Added BMP options
    • Sector N: Added option of storing recyclables indoors or minimizing exposure
  • Sub-sector S3 definition: Changed to: “non-propeller aircraft departures”
  • Sector S: For airports with no de-icing activities, sample for TSS only.  For all airports, remove pH sampling requirement.

Appendix A

  • Anti-degradation review complete: no additional changes beyond what’s proposed above.

2013 - 2015

  • April 5, 2015: Permit is re-issued and becomes effective

2015 documents

2006 - 2010

The MPCA began work to reissue the expired General Stormwater Permit for Industrial Activity. 

2010 documents

2002 - 2003


The 1997 General Stormwater Permit for Industrial Activity Permit MN G611000 expired on October 31, 2002. Before the permit expired, the MPCA drafted the Industrial Stormwater Permit and public noticed the draft for comments:

During the public notice comment period, the MPCA received written comments on several issues including requirements for outstanding resource value waters and nondegradation analysis, requirements for completed total maximum daily loads, monitoring, and SWPPPs.

In the interim, to address the time between the expired permit and reissuance of the new General Stormwater Permit for Industrial Activity, previous permit holders were covered by Minn. R. 7001.0160. “Any person who holds an expired permit…and who has submitted a timely application for reissuance of the permit may continue to conduct the permitted activity in accordance with the terms and conditions of the expired permit until the agency takes final action on the application.”

New, non-municipal facilities and newly regulated municipally owned or operated industrial facilities had to submit a permit application in order to meet the federal requirements of applying for NPDES permit coverage for industrial activity. Until the general permit was reissued, facilities had to develop and implement a SWPPP that complied with the Draft NPDES General Stormwater Permit for Industrial Activity which included the SWPPP requirements contained in the expired permit. 


EPA’s Stormwater Phase II regulations became effective on March 10, 2003, and continued to regulate the ten categories of industrial activity:

  1. Facilities subject to stormwater effluent limitation guidelines, new source performance standards, or toxic pollutant effluent standards under 40 CFR Subchapter N
  2. Heavy industrial facilities (SIC codes 24, 26, 28, 29, 311, 32,33,3441, 373
  3. Mineral industry (SIC codes 10, 12, 13, 14)
  4. Hazardous waste treatment, storage or disposal facilities
  5. Landfills, land application sites and open dumps that receive or have received industrial waste
  6. Facilities involved in recycling of material, including metal scrap yards, battery reclaimers, salvage yards, and automobile junk yards, including but limited to those classified as SIC codes 5015 and 5093
  7. Steam electric power generating facilities
  8. Transportation facilities (SIC codes 40, 41, 42 [except 4221-25], 43, 44, 45 and 5171 which have vehicle maintenance shops, equipment cleaning operations, and airport deicing operations
  9. Sewage treatment works
  10. Light industrial facilities (SIC codes 20, 21, 22, 23, 2434, 25, 265, 267, 27, 283, 285, 30, 31, 323, 34, 35, 36, 37, 38, 39, 4221, 4222 and 4225)

The regulations extended the No Exposure exclusion to all industrial stormwater categories and required municipally owned or operated industrial facilities to obtain permit coverage or certify No Exposure.