MS4 Program

In effort to reduce stormwater pollution, and improve local water quality, Salisbury Township must develop, implement, and enforce a Stormwater Management Program (SWMP). This task is required by the National Pollutant Discharge Elimination System (NPDES) permit, issued through the Pennsylvania Department of Environmental Protection (PA DEP) & the United States Environmental Protection Agency (US EPA).  The NPDES permit regulates stormwater discharges from the Township’s municipal separate storm sewer system (MS4): a series of inlets, pipes, swales, outfalls, and other drainage facilities that collect, convey, and discharge stormwater directly into our streams

What is an MS4?

MS4 stands for Municipal Separate Storm Sewer System. MS4s are conveyances or systems of conveyances including roads with drainage systems, municipal street, catch basins, curbs, gutters, ditches, man-made channels, or storm drains that are owned or operated by a public entity, are designed or used for collecting or conveying stormwater, and are not a combined sewer or part of a publicly-owned treatment wastewater treatment plant.

A Municipality is bound by the US Environmental Protection Agency (EPA) regulations associated with the Federal Clean Water Act for MS4s when all or a portion of a municipality lies within an urbanized area (UA), as determined by the US Census Bureau. Approximately 5% of SalisburyTownship is considered urbanized area.

The PADEP has provided a streamlined process for Municipalities to meet State and Federal stormwater requirements. Operators of an MS4, such as Salisbury Township, must obtain a National Pollutant Discharge Elimination System (NPDES) permit and develop and implement a stormwater management plan (aka MS4 Program). Mandatory elements of the stormwater management plan include 6 minimum control measures (MCM); each MCM has a number of associated Best Management Practices (BMPs). These 6 MCMs include public education and outreach, public involvement and participation, illicit discharge detection and elimination, construction site runoff control, post-construction stormwater management and pollution prevention and good housekeeping.

Your Responsibility as a Homeowner in Salisbury Township:

If you have a storm water management facility, such as a swale, basin, inlet, or outlet structure, most likely, you are responsible for maintenance of the facility. This could include simply mowing these areas and keeping them free from structures, to making sure the rip rap (dispersing rocks) is replaced as needed, that pipes are not clogged, or possibly replacing malfunctioning facilities. 

Salisbury Township in conjunction with PA Department of Environmental Protection has made the brochure "When it Rains, It Drains" available for download. This brochure explains stormwater runoff, and what you can do to improve the water quality in our area.

Another good brochure to read is Landscaping Maintenance.

What is an illicit discharge?

An illicit discharge is defined as any discharge to an MS4 that is not composed entirely of storm water (with some exceptions). Illicit discharges are considered “illicit” because MS4s are not designed to accept, process, or discharge such non-stormwater wastes. Sources of illicit discharges can include sanitary wastewater, effluent from septic tanks, improper oil disposal, laundry wastewater, spills from roadway accidents or improper disposal of auto and household toxics, grass and leaf dumping into storm inlets, swales, streams and rivers, wetlands, and floodplains.

Illicit discharges enter the system through either direct connections (e.g., wastewater piping either mistakenly or deliberately connected to the storm drains) or indirect connections (e.g., infiltration into the MS4 from cracked sanitary systems, spills collected by drain outlets, or paint or used oil dumped directly into a drain).

The result is untreated discharges that contribute high levels of pollutants, including heavy metals, toxics, oil and grease, solvents, nutrients, viruses, and bacteria to receiving waterbodies. Pollutant levels from these illicit discharges have been shown in EPA studies to be high enough to significantly degrade receiving water quality and threaten aquatic, wildlife, and human health.

How to report an illicit discharge

To report an illicit discharge or connection please complete the illicit discharge Report Form or call the Township office at 717-768-8059 or email  If calling after regular business hours, please leave a message on the road emergency line.  DEP also has a 24 Hour Emergency (1-800-541-2050) number in case there is a major spill event after hours.

The following agency links provide additional stormwater information:



Lancaster Clean Water Partners

Lancaster Countywide Action Plan – Lancaster Clean Water Partners

Lancaster County Conservation District

Lancaster County Watersheds 

Lancaster Farmland Trust