Industrial stormwater: Permit development and program history

The 1972 amendments to the federal Water Pollution Control Act (known as the Clean Water Act or CWA) provide the statutory basis for the National Pollutant Discharge Elimination System (NDPES) permit program and the basic structure for regulating the discharge of pollutants from point sources to waters of the United States. Section 402 of the CWA specifically required EPA to develop and implement the NPDES program. The CWA allowed EPA to authorize the NPDES Permit Program to state governments, enabling states to perform many of the permitting, administrative, and enforcement aspects of the NPDES Program. In states that have been authorized to implement CWA programs, EPA still retains oversight responsibilities.

According to the National Water Quality Inventory, stormwater runoff is a leading source of water pollution. Stormwater at industrial facilities may come into contact with harmful pollutants including toxic metals, oil, grease, de-icing salts, and other chemicals from rooftops, roads, parking lots, and from activities such as storage and material handling.

Stormwater discharges potentially containing the above pollutants are associated with 10 categories of industrial activities. These activities are regulated through NPDES permits. Facilities that need an NPDES permit must develop and implement a Stormwater Pollution Prevention Plan that is designed to eliminate or minimize stormwater contact with significant materials that may result in polluted stormwater discharges from the industrial facility. The SWPPP must also incorporate specific BMPs applicable to the facility.

2013 - 2015

  • October 2013: MPCA staff compare USEPA's draft MSGP with Minnesota MSGP
  • November - March 2014: Draft suggested changes into draft permit
  • March 31 - April 30, 2014: 30-day public notice period for the MPCA draft permit
  • May / June 2014: MPCA staff make changes to draft permit in response to public comments
  • Late June 2014: Estimated date the draft permit is approved
  • July 7 - October 5, 2014: Time to re-apply / re-certify for permit coverage / No Exposure
  • April 5, 2015: Permit is re-issued and becomes effective

2015 documents

What changed in the 2015 permit?

Streamlined sampling requirements: All existing permittees who apply between July 7, 2014, and October 5, 2014, would conduct a year of quarterly sampling starting July 1, 2015. Any permittee who applies after April 5, 2015 will start sampling requirements during the next full calendar quarter.

Requiring four samples before averaging: Permittees will be required to collect a minimum of four samples, during four separate calendar quarters, before averages can be calculated and compared with the permit's benchmark value(s). It is acceptable if it takes more than four quarters to collect four samples; this may be because samples couldn't be collected due to drought/frozen conditions or no off-site discharges. These are considered legitimate "no flow" explanations.

Quarterly sampling until benchmark values: Permittees with exceedances will continue sampling quarterly until four quarters of averaged results are below the benchmark value.

Limitations on infiltration:  Construction of a new infiltration device is prohibited in:

  1. Areas that receive discharges from vehicle fueling and maintenance activity.
  2. Areas with less than three feet of separation distance from the bottom of the infiltration device to the elevation of the seasonally saturated soils to the top of the bedrock.
  3. Areas of predominantly Hydrologic Soil Group D (clay) soils unless allowed by a local unit of government with a current MS4 permit.
  4. Areas where soil infiltration rates are more than 8.3 inches per hour unless soils are amended to slow the infiltration rate below 8.3 inches per hour or as allowed by a local unit of government with a current MS4 permit.

Commonly asked questions and answers

Q:  When do I need to re-apply for Permit coverage or No Exposure now?
  The Industrial Stormwater Permit and MN Rule require all existing Permittees to apply at least 180 days before Permit expiration. The application period is July 7, 2014, through October 5, 2014, for all applicants; all Permittees and all No Exposure Certifiers.

Q:  I closed my facility/terminated. How do I formally notify the MPCA?
A: Microsoft Office document icon Industrial Stormwater Notice of Termination Form

Q:  How do I know if I have “Year 5” sampling requirements?
A:  While the calendars will be automatically updated about 2 months after “Year 4” is over, the Permittee can manually average their own sampling results and if they exceed the benchmark values, that Permittee will have “Year 5” sampling requirements.

Please note that the current permit and all of the current requirements have an expiration date for all Permittees and No Exposure Certifiers of April 5, 2015. The proposed requirements within the 2015 Permit began April 5, 2015.

2006 - 2010

The MPCA began work to reissue the expired General Stormwater Permit for Industrial Activity. Key steps along the way included:

November 2006: MPCA created the Stormwater Steering Committee’s Industrial Stormwater Work Group. It was made up of members of the Minnesota Stormwater Steering Committee and public and private organizations. The Work Group’s task was to help the Industrial Stormwater Program draft the new permit.

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.