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<div title="A municipal separate storm sewer system (MS4) is a means of transportation, individually or in a system, (e.g. roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, storm drains, etc.) that are:
 
<div title="A municipal separate storm sewer system (MS4) is a means of transportation, individually or in a system, (e.g. roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, storm drains, etc.) that are:
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<ul>
 
<li>1 owned or operated by a public entity (e.g. cities, townships, counties, military bases, hospitals, prison complexes, highway departments, universities, etc.) with jurisdiction over disposal of sewage, industrial wastes, stormwater, or other wastes. This includes special districts under State law (sewer, flood control, or drainage districts, etc.), an authorized Indian tribal organization, or a designated and approved management agency under section 208 of the Clean Water Act</li>
 
<li>1 owned or operated by a public entity (e.g. cities, townships, counties, military bases, hospitals, prison complexes, highway departments, universities, etc.) with jurisdiction over disposal of sewage, industrial wastes, stormwater, or other wastes. This includes special districts under State law (sewer, flood control, or drainage districts, etc.), an authorized Indian tribal organization, or a designated and approved management agency under section 208 of the Clean Water Act</li>
 
<li>2 designed or used for collecting or transporting stormwater</li>
 
<li>2 designed or used for collecting or transporting stormwater</li>
 
<li>3 not a combined sewer</li>
 
<li>3 not a combined sewer</li>
<li>4 not part of a publicly owned treatment works</li>">
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<li>4 not part of a publicly owned treatment works</li>
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/ul>">
 
*<u>What is a municipal separate storm sewer system (MS4)?</u>
 
*<u>What is a municipal separate storm sewer system (MS4)?</u>
 
</div>
 
</div>

Revision as of 16:50, 29 April 2024

Information: We recently updated this page and will continue to work on information about MS4 stormwater management. If you have suggestions, we welcome comments using the comment box at the bottom of most pages in the manual.
icon for MS4 stormwater

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.


<div title="A municipal separate storm sewer system (MS4) is a means of transportation, individually or in a system, (e.g. roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, storm drains, etc.) that are: