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Evidence of an illicit discharge - white paint at a storm sewer outfall to one of Duluth's creeks

Where can I find more information on the State NPDES Phase II permit?
MPCA web page

Report Discharges to:
Duluth Stormwater
(218) 730-4130

Find out more...

Illicit Discharges


What is an Illicit Discharge?

An Illicit Discharge is the result of an illegal and/or improper waste discharge into storm drainage systems and receiving waters.

The state definition of stormwater is "stormwater runoff, snow melt, surface runoff and drainage".  Nothing else can go down the storm sewer unless permitted by the MPCA (such as clean cooling water and industrial discharges).

Illicit discharges may result from the connections of non-stormwater conveyance facilities (such as sanitary sewers) to the storm water system or may be the result of a waste spill flowing overland and into a storm sewer.

An example of an illicit connection would be the connection of a floor drain in a restaurant or automotive repair garage to a storm sewer. This would result in non-storm water wastes being flushed into the storm sewer system anytime the floors are washed in either facility. An example of an illicit discharge (without an illicit connection) would be the flushing of used motor oil down a storm sewer catchbasin rather than properly recycling the waste oil.


Why is Duluth Concerned about Illicit Discharges?

The City of Duluth contains 42 creeks, 12 of which are protected trout streams. The citizens of Duluth have repeatedly demonstrated that the quality of the environment is extremely important. As such the City of Duluth has made a commitment to protect and preserve the quality of the creeks within its jurisdiction.

Additionally, the Environmental Protection Agency, through the Minnesota Pollution Control Agency (MPCA) is requiring the City of Duluth to obtain coverage to operate the City's storm sewer system under the Nationwide Pollution Discharge Elimination System (NPDES) permit program. This program has the primary goal of maintaining and restoring the chemical, physical, and biological integrity of surface waters within the United States. One element of this permit program requires the identification and elimination of non-stormwater (illicit) discharges to the storm sewer system.


How will Duluth find and eliminate existing Illicit Discharges?

The City of Duluth has developed a program to inspect for illicit discharges along each watercourse in the 30 watersheds located within the city limits. The City initiated this program in June 2002 when they held a 7-hour college accredited Illicit Discharge Training seminar for 17 members of the utility operations department.

Under the illicit discharge program, Utility Operations Water Quality Specialists investigate all reports of suspicious materials in the storm sewers, creeks or streams. In addition the outfall inspection program is completed on a rotational basis. Outfalls are inspected that discharge to trout streams, Lake Superior and the St. Louis River as well as wetlands. When suspicious discharges are detected at the mouth or in small streams additional inspections occur. The City inspects approximately 150 to 200 outfalls yearly for condition and presence of suspcious discharge. GPS survey equipment is used to identify the coordinates of each storm sewer outfall, and where necessary the City's GIS database is updated to indicate the location of each outfall.

As inspections are completed reports will be generated indicating that no illicit discharges were detected or identifying the location where the discharge was detected. When discharges are detected, advanced investigation techniques such as dye testing and sewer televising will be conducted to identify the source of the discharge. Once the source is located legal and administrative activities will be initiated requiring the owner of the facility where the illicit connection is located to eliminate the connection or the cease the illicit activity.


How does the City prevent new illicit discharges?

The City of Duluth currently has ordinances in place prohibiting illicit discharges to the storm water system. Chapter 43 of the rules refers to Sewers and Sewage Disposal. Section 16, 'Connection to City Sewer System Required,' specifically requires that all owners of houses, buildings, or properties of any character wherein wastewater (defined as polluted water or water that would violate receiving water quality standards) must be connected to suitable wastewater collection facilities. Section 40, 'Use of Storm Sewers,' prohibits connections to storm sewers for anything other than unpolluted water from such sources as stormwater, groundwater, subsurface drainage, unpolluting industrial process or cooling water. These two provisions effectively prohibit illicit connections to the City's storm sewer system.

In March 2003 the City of Duluth submitted a Notice of Intent to be part of the state General NPDES Phase II stormwater Permit. The new 2006 permit application can be downloaded here (700 KB pdf).