Municipal Separate Storm Sewer System (MS4)


Greene Township was notified during the summer of 2016 by the Department of Environmental Protection (DEP) that the urbanization and development of the Township had grown to the point, based on the 2010 census, that we are now classified as an MS4 community. This designation requires the Township to create a plan consistent with the requirements outlined by DEP that addresses improving and also maintaining the quality of all the discharges into our streams and watercourses located within the Township.

Since the passage of the Clean Water Act (CWA) in 1972, the quality of our Nation’s waters has improved dramatically. Despite this progress, however, degraded waterbodies still exist. Approximately 40 percent of surveyed U.S. waterbodies are still impaired by pollution and do not meet water quality standards. A leading source of this impairment is polluted runoff that has been created by the increase in impervious surfaces as a result of the developing urbanization that has occurred from the growth in population in the Township. Polluted stormwater runoff is commonly transported through municipal separate storm sewer systems (MS4s), and then often discharged, untreated, into local water bodies.

An MS4 is a conveyance or system of conveyances of ditches, pipes and ephemeral waterways that discharge to waters of the U.S.  To prevent harmful pollutants from being washed or dumped into specific types of MS4s, Municipalities are required to obtain National Pollutant Discharge Elimination System (NPDES) permits and develop stormwater management programs.

Stormwater discharges from MS4s in urbanized areas are a concern because of the high concentration of pollutants found in these discharges. Concentrated development in urbanized areas substantially increases impervious surfaces, such as streets, driveways, parking lots, and sidewalks, on which pollutants from concentrated human activities settle and remain until a storm event washes them into nearby storm drains. Common pollutants include oil and grease from roadways, pesticides from lawns, sediment from construction sites, and carelessly discarded trash, such as cigarette butts, paper wrappers, and plastic bottles.

When deposited into nearby waterways through MS4 discharges, these pollutants can impair the waterways, thereby discouraging recreational use of the resource, contaminating drinking water supplies, and interfering with the habitat for fish, other aquatic organisms, and wildlife.

Municipalities qualifying as MS4 communities, are required to implement stormwater discharge management controls – known as “best management practices” (BMPs). An MS4 community must develop, implement, and enforce a stormwater management program designed to reduce the discharge of pollutants from their MS4 to the “maximum extent practicable,” to protect water quality, and to satisfy the appropriate water quality requirements as mandated by NPDES regulations.

Greene Township is currently developing a plan which addresses our permitting requirements. As a part of the plan there is a component which requires the Township to complete planning to develop Public Education and Outreach and also Public Participation and Involvement. The success of any plan is dependent on the commitment of the community to embrace the plan’s goals to insure that our network of streams and waterways are kept clean and pollutant free.  Please take time in the upcoming months and years as the plan is implemented to become educated on the things you can do to make it a success. You are invited to contact the Township for further information concerning our MS4 Plan.


Greene Township Chesapeake Bay Pollutant Reduction Plan

Greene Township MS4 Mapping (Ongoing)


What is MS4?

Pennsylvania’s Chesapeake Bay Plan

How to Be Stormwater Smart

Stormwater PA

Chesapeake Stormwater Network

Alliance for the Chesapeake Bay

EPA Stormwater Program

Franklin County Conservation District – Erosion & Sediment Control Program

Creek Cleanup Project