What is an MS4 Stormwater System?

An MS4 is a municipal separate storm sewer system that conveys stormwater from inlet to outfall.  This may include roads with drainage systems, municipal streets, catch basins, curbs & gutters, ditches, man-made channels and storm drains.

The City of Forest Lake is designated as an MS4. This mandate required the City of Forest Lake to obtain an NPDES permit and prepare a SWPPP by February 2007.