What is an MS4?

Municipal Separate Storm Sewer System (MS4) is a system of conveyances including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains. As stormwater runs over driveways, lawns, and sidewalks it picks up debris, chemicals, dirt, and other pollutants.

Polluted stormwater runoff is often conveyed to MS4s and ultimately discharged into local rivers and streams without treatment. Anything that enters a storm sewer system is discharged into the water bodies we use for recreation and providing drinking water. Polluted runoff is the nation’s greatest threat to clean water.



How Can Your Household Help?

By practicing healthy household habits, homeowners can keep common pollutants like pesticides, pet waste, grass clippings, and automotive fluids off the ground and out of stormwater. For more information, please visit the Department of Environmental Protection’s (DEP) website.

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Illicit Discharges

An illicit discharge is defined as any unauthorized discharge other than clean stormwater released into the Municipal Separate Storm Sewer System (MS4). Illicit connections may be intentional or may be the result of connections made years ago when water quality issues were not a concern.

The types of illicit discharges vary widely with some examples being:

  • Waste oil, antifreeze, paint, trash or other household chemicals
  • Car wash, laundry, and industrial wastewaters
  • Pool water discharge (chlorinated and dechlorinated) – Tips for disposal by DEP can be found here
  • Spills on roadways and other accidents
  • Failing septic systems and illegal dumping practices
  • Improper disposal of sewage from recreational practices such as boating or camping

Common indicators of illicit discharges include abnormal odors, strange colors, or oil sheen present around or inside storm inlets or pipes. Keeping harmful substances out of our water benefits everyone; environmentally and economically.

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Proper Pool Water Discharge Management

Discharged pool water can contain chlorine or other chemicals that are harmful to our local waterways if not managed correctly. Before you close your pool for the year, please check out this article by the Pennsylvania Department of Environmental Protection on how to properly  manage your pool water discharge. 

Helpful Documents/Links

Upper Allen Township Stormwater Ordinance

A Homeowner's Guide to BMP Maintenance

Stormwater PA: Clean Your Water

Chesapeake Bay Alliance: Get Involved

For questions regarding the MS4 Stormwater Program:

Garrett Vandebrake, Stormwater Program Manager

100 Gettysburg Pike
Mechanicsburg, PA 17055
Telephone: 717-766-0756/717-591-3767

Mail: gvandebrake@uatwp.org

If you witness or become aware of an illicit discharge or illegal dumping, please contact:

Collin Barge, MS4 Coordinator

100 Gettysburg Pike
Mechanicsburg, PA 17055
Telephone: 717-766-0756/717-756-9169

Mail: cbarge@uatwp.org