MPCA Industrial Storm Water Permit - Revised Draft

On March 19, 2009, the Minnesota Pollution Control Agency (MPCA) released a revised working draft of its proposed multisector industrial stormwater discharge general permit. This permit, once promulgated, will replace the existing industrial stormwater permit, which expired in October of 2002.

The March 19, 2009 draft including a number of revisions and additions to the previous draft released on November 13, 2008.

[Read a summary of the November 13, 2008 draft MPCA Industrial Stormwater General Permit]

Some of the key updates in the March 19, 2009 draft include:

Pollution Prevention Requirements:
Additional pollution prevention requirements have been included under each sector-specific requirement (discussed below)

Stormwater Monitoring Requirements:
There are no significant changes to the requirements for all dischargers to conduct both visual and chemical (benchmark) monitoring. However, some important changes related to stormwater monitoring are including in Sector Specific Monitoring Requirements (see sector requirements)
[Read about proposed MPCA industrial stormwater monitoring requirements]
[See flowchart summarizing proposed MPCA industrial stormwater monitoring requirements]

Stormwater Antidegradation Requirements:
Certain discharges that are located within one mile of a “special water” must meet additional requirements. The March 19, 2009 contains no significant amendments to stormwater nondegradation (antidegradation) requirements compared to the previous draft.
[Read more about MPCA stormwater nondegradation (antidegradation) requirements]

Stormwater Infiltration Requirements:
The requirements for stormwater infiltration is largely the same as discussed previously. There now is clarification that design standards for infiltration basins must be met for new basins or when upgrading existing basins.
[Read more about draft requirements for stormwater infiltration]

Sector Specific Requirements:
One of the key changes compared to the previous working draft is the addition of sector specific requirements. The general permit will ultimately contain additional requirements for about thirty different industrial sectors. Most sectors now have sector requirements listed.

As examples, click below to review additional requirements for two sectors:

Proposed stormwater requirements for Food and Kindred Products Sector (Sector U)
Proposed stormwater requirements for Steam Electric Generating Facilities (Sector O)

Looking for other sector information? Click here to request information on proposed stormwater requirements for specific sector.


The March 19, 2009 draft for the industrial stormwater discharge general permit is a “work in progress”; it is anticipated that requirements will change prior to being published for public review and comment.

Caltha LLP provides expert environmental consultant services in Minnesota to obtain air and wastewater permits, evaluate regulatory requirements, and to develop cost effective compliance programs.

For further information, contact Caltha LLP at:
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