What is MS4?


This page provides general information for residents who want to educate themselves about the MS4 program and understand the role we all play in keeping our water clean.  (For ordinance/plan information, and applications, click here.)

NPDES and MS4 Programs

NPDES (National Pollutant Discharge Elimination System)
MS4 (Municipal Separate Storm Sewer System)

The Clean Water Act is the federal legislation that governs stormwater management. Storm water point discharges to waters of the U.S. (pipes and drain pipes), and are regulated using NPDES permits. In 1999, federal regulations extended coverage of the NPDES program to local separate storm sewer systems (MS4’s) serving populations less than 100,000.

Lancaster Township is required to comply with the NPDES program as a MS4 municipality. Under the NPDES storm water program, permittees must develop a stormwater management plan that provides the details of how the community will comply with the requirements of the permit. Permits are based on a framework of six minimum control measures:

  • Public education and outreach
  • Public participation and involvement
  • Illicit discharge detection and elimination
  • Construction site runoff control
  • Post-construction storm water management in new development and redevelopment
  • Pollution prevention and good housekeeping for municipal operations and maintenance

Lancaster Township is actively involved in a variety of programs and initiatives to meet various statewide and national goals for clean water, but township residents have a role to play too. Working together, we will have a positive impact on our environment, and the water that is so important to us all. We hope that you will find this information useful.

What is storm water runoff?

Storm water originates from rain or melting snow/ice that runs off surfaces such as rooftops, streets, construction sites, lawns, and fields. Storm water runoff can pick up debris, chemicals, dirt, and other pollutants as it makes its way to storm drains and natural waterways.

Why should you care?

Storm water from your home and from the public streets goes into a storm sewer, which goes directly into streams and bodies of water used for swimming, fishing, and providing drinking water. This water is not cleaned in any way and does not go to the waste water treatment plant. We all drink water, so we are all affected when our water is polluted. Streams and creeks feed into rivers, lakes and the ocean. If you like to fish, swim or boat, pollutants will affect you. When we pollute our water, everyone is affected!

What can you do to help?

  • plant native trees & plants
  • clean up after your pets
  • use fertilizers properly and efficiently to prevent excess runoff
  • store gasoline, oil, or other chemical materials indoors
  • monitor storm water inlets near your property
  • NEVER dump anything down the storm drain, in a stream, or other body of water

Managing storm water on your property will not only help protect local streams, but will also help clean up downstream waterways including the Chesapeake Bay.