MS4 (Municipal Separate Storm Sewer System)

The federal Environmental Protection Agency (EPA) mandates that Honey Brook Township has a comprehensive storm water management program which is monitored by the Pennsylvania Department of Environmental Protection (PADEP).  The program is designed to literally “manage” stormwater, both by protecting water quality and by preventing high volumes of runoff from causing flooding in developed areas.  Any municipality with a population of at least 5,000 must comply with the program.


The origin of the Municipal Separate Storm Sewer System (MS4)

The Clean Water Act (CWA) establishes the basic structure for regulating discharges of pollutants into the waters of the United States and regulating quality standards for surface waters.  The CWA made it unlawful to discharge any pollutant from a point source into navigable waters, unless a permit was obtained.  The EPA’s National Pollutant Discharge Elimination System (NPDES) permit program controls discharges.  Point sources are discrete conveyances such as pipes or man-made ditches.  Individual homes that are connected to a municipal system, use a septic system, or do not have a surface discharge do not need an NPDES permit; however, industrial, municipal, and other facilities must obtain permits if their discharges go directly to surface waters.   The CWA is the driving force behind the Municipal Separate Storm Sewer System (MS4) requirements.

What is a Municipal Separate Storm Sewer System (MS4)?

The MS4 includes any roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains designed or used for collecting or conveying stormwater that are owned or operated by a public body that are not part of a publicly owned treatment works.

A storm drainage system is very important to keeping runoff from flooding roadways and damaging property.  Inlets in the streets are interconnected by piping and eventually discharged to a larger pipe, a stream, or ditch.  These inlets are typically located at low points of streets in order to efficiently collect rainwater.  Residents may help everyone by ensuring that inlets are free and clear of leaves and other debris prior to a rain storm.  If an inlet is clogged and not accepting runoff, the Roads Department should be called at (610) 273-3084.

Streams and drainage ditches/swales are also conveyors of the runoff.  Dumping or raking leaves and other garden debris into these channels hurts the environment and seriously impacts drainage down stream.  Remember, eventually all of our runoff ends up in the Brandywine River.

Honey Brook Township’s MS4

Stormwater pollution is caused by so many different activities that traditional regulatory controls cannot handle the problem.  Polluted storm runoff is often transported to MS4s and ultimately discharged into local rivers and streams without treatment.  The Environmental Protection Agency’s Storm Water Phase II Rule outlines the regulatory requirements for an MS4 program intended to improve the nation’s waterways by reducing the quantity of pollutants that storm water picks up and carries into storm sewer systems during storm events.  Since 2003, Honey Brook Township’s MS4 permit has helped the Township satisfy the requirements of the Clean Water Act (CWA) under the Small MS4 Program. The MS4 permit requires the Township to implement and enforce a storm water management program in its defined “urbanized areas”* and to address the six minimum control measures (MCMs) listed below.

1.  Public Education and Outreach: Distributing educational materials and performing outreach to inform citizens about the impacts polluted storm water runoff discharges can have on water quality.  Click here for more.

Click here for the MS4 Quick Resource Guide.

2.  Public Participation and Involvement: Providing opportunities for citizens to participate in program development and implementation, including effectively publicizing public hearings and/or encouraging citizen representatives on a storm water management panel.  Click on the following for more information:

Brandywine Conservancy
Brandywine Creek Greenway
Brandywine Red Clay Alliance (formerly the Brandywine Valley Association–BVA–and the Red Clay Valley Association)
BRCA Events/Seminars

3. Illicit Discharge Detection and Elimination:  Developing and implementing a plan to detect and eliminate illicit discharges to the storm sewer system (including developing a system map and informing the community about hazards associated with illegal discharges and improper disposal of waste.)

Illicit Discharges are defined by federal regulations as any discharge to the storm sewer system that is not composed entirely of stormwater.  There are exceptions to this rule such as firefighting activities, landscape irrigation, foundation drains, water from crawl space pumps etc.  Sources of illicit discharges include:

  •  sanitary wastewater
  • failing septic systems
  • car wash waste water
  • improper oil disposal
  • radiator flushing disposal
  • spills from roadway accidents
  • improper disposal of household toxics or improper use of pesticides and herbicides etc.

Illicit discharges enter the system either through direct connections (deliberate pipe hookups to the storm drain system) or indirect connections (spills collected by drain outlets, or deliberate dumping down the storm drain.) These illicit discharges drain directly to the creeks and streams and may be loaded with a large amount of harmful and toxic substances.  These pollutants enter the aquatic system and degrade the water quality and threaten wildlife and human health.  Those who allow prohibited discharge to enter the Municipal Separate Storm Sewer System (MS4) are in violation of the Stormwater Management Ordinance and can be subject to a fine.

Read about the Illicit Discharge Ordinance, #157-2011, by clicking here.

See also Ordinance 173-2014, passed on May 14, 2014.

Please remember that water, and any items that go into a storm sewer, goes directly into local streams. This water is not cleaned in any way and does not go to a waste water treatment plant. Residents can assist in keeping our stormwater and stormwater system clean by referring to the suggestions on the Stormwater page.

Please monitor stormwater inlets near your property.  Stormwater itself is unavoidable, but its effects can be reduced by keeping harmful chemicals and materials out of the runoff.  No one should dump anything directly into a storm sewer.  If you see someone dumping, please call the Honey Brook Township Administration Office at 610-273-3970 or the DEP Water Quality Hotline at 484-250-5900.  For information on how to report suspected illicit discharges, click here.

For more information on illicit discharge detection and control, click here.

There is a 5-video set on illicit discharge detection & elimination (IDDE). The videos define illicit discharges, identify the damages to surface waters, and show citizens what they can to do to help prevent them.  Click now to watch online -> IDDE Public Outreach.

For more info on these videos, call Excal Visual at 888-925-6554 or e-mail

4.  Construction Site Runoff Control:  Developing, implementing, and enforcing an erosion and sediment control program for construction activities that disturb one or more acres of land (controls could include silt fences and temporary storm water detention ponds).  Click here for more.

5. Post-Construction Runoff Control:  Developing, implementing, and enforcing a program to address discharges of post-construction storm water runoff from new development and redevelopment areas.  Applicable controls could include preventative actions such as protecting sensitive areas (e.g., wetlands) or the use of structural BMPs such as grassed swales or porous pavement.  For more information, click here.

6.  Pollution Prevention / Good Housekeeping:  Developing and implementing a program with the goal of preventing or reducing pollutant runoff from municipal operations.  The program must include municipal staff training on pollution prevention measures and techniques (e.g., regular street sweeping, reduction in the use of pesticides or street salt, or frequent catch-basin cleaning) or its chosen Best Management Practices (BMPs) and measurable goals for each minimum control measure.  To help permittees identify the most appropriate BMPs for their programs, the Environmental Protection Agency (EPA)will issue a “menu” of BMPs to serve as guidance.  National Pollutant Discharge Elimination System (NPDES)-permitting authorities can modify the EPA menu or develop their own list. For more information, click here.


The application for the 5-year MS4 permit renewal for the period ending in March 2023 was submitted in September 2017.  Part of that permit renewal application was including a Total Maximum Daily Load [of pollutants] (TMDL) Plan and a Pollutant Reduction Plan (PRP) which must be achieved over the course of the permit cycle for each of the urbanized areas* draining to impaired streams segments.

*Honey Brook Township’s Urbanized Areas include:

  • Western area:  the southwestern corner of the township, which drains into the Chesapeake Bay.  The Township’s proposed BMP is to convert an existing grass drainage swale in the Evergreen Ridge development into a bioswale with specialized soils and plantings to promote water quality in an effort to reduce pollutant loads by 10% for sediment, 5% for phosphorus, and 3% for nitrogen.
  • Eastern area:  this area does not drain into any impaired stream segments and therefore is not required to be counted in the TMDL calculations.
  • Central area:  the area including and surrounding Honey Brook Borough, which drains into the Delaware Bay.  This area’s proposed BMP is a joint plan with the Borough and includes a forested buffer along a stream on an agricultural property, and tree planting and a rain garden installation in the James A. Umble Memorial Park.




Last update:  February 5, 2019.