The municipal separate storm sewer system (MS4) stormwater program is designed to reduce the amount of sediment and pollution that enters surface and ground water from storm sewer systems. Public entities that own or operate an MS4 play a key role in preventing or reducing the negative impacts stormwater runoff has on our valuable water resources.
Proper stormwater runoff management in urbanized areas is especially important for restoring and protecting surface waters. Urbanized areas are more likely to have activities that contribute pollutants to stormwater runoff, like applying anti/deicing mixtures to roads; fueling vehicles; grease, oil, and other spills; landscaping; and using pesticides and fertilizers. Urbanized areas have a large amount of impervious surfaces, or surfaces that rain and snowmelt cannot pass through, such as streets, driveways, rooftops, parking lots and sidewalks. Stormwater runoff from these surfaces travels faster and in higher amounts, damaging rivers, streams, and wetlands; destroying aquatic habitats; increasing the amount of pollutants that enter surface waters; and limiting groundwater recharge.
Visit the MS4 General Permit reissuance page for updates on the next MS4 General Permit.
The municipal separate storm sewer system (MS4) toolkit is a collection of resources the MPCA has pulled together for stormwater program staff. It is intended to help entities regulated under the MS4 program meet the requirements of the general permit. It offers a wide range of downloadable stormwater education information including sample fact sheets, newsletters, videos, and other resources.
The MS4 Digital Document Library provides guidance to help local MS4 staff meet the requirements of the six minimum control measures (MCMs) in the MS4 General Permit and assist with overall stormwater management. In addition to general guidance documents, the Digital Document Library has example documents that stormwater staff are using to manage their stormwater pollution prevention programs (SWPPPs). Common examples of documents in the library include:
All documents in the Digital Document Library are available for all site users to download and use. MPCA staff will review all materials to ensure their compliance with the MS4 General Permit prior to posting in the Digital Document Library.