Stormwater is water from precipitation that comes in many different forms including rain, sleet, snow and ice.  The goal of Stormwater Management is to control this precipitation to the fullest extent possible.  Construction of new impervious surfaces, such as homes, driveways, sheds, parking lots, etc.  add additional water to the storm sewer system as well as pollutants.

Through the Municipality’s Stormwater Ordinance and the implementation of the Municipal Separate Storm Sewer System (MS4) permit, Bethel Park seeks to control water at the source in order to mitigate flooding and improve the quality of the stormwater entering the creeks and streams.

What is the MS4 Program?

The MS4 Program is administrated by the Pennsylvania Department of Environmental Protection.  The EPA defines MS4 as “A conveyance or system if conveyances that is not part of a public water treatment plant or other public entity that collects water in storm drains, ponds, etc., and not a combined sewer”. MS4 regulations, issued in the early to late 1990’s required population centers of varying sizes, to permit for coverage of stormwater discharges.  Permits for small population centers, as well as urbanized population centers must be obtained from the National Pollutant Discharge Elimination System (NPDES).

What is required under an MS4 Program?

All MS4 programs that are permitted by NPDES must include six Minimum Control Measures (MCMs).  The MCMs are:

    1. Public Education and Outreach on Stormwater Impacts
    2. Public Involvement and Participation
    3. Illicit Discharge detection and Elimination
    4. Contruction Site Stormwater runoff Control
    5. Post – Construction Stormwater Management in new and re-developed areas
    6. Pollution Prevention / Good Housekeeping for Municipal Operation

Why is storm water sewer management important?

Pollutants in storm water is one of the largest concerns surrounding water runoff.  Because storm water ultimately works its way into local streams and creeks, the quality of the water is affected by any pollutants that run off into the storm sewers along with water.  Here are some common, every day pollutants that affect storm water runoff:

  • Dog waste
  • Yard Fertilizers
  • Swimming pool discharge

Pollutants are not the only concern, however.  Storm water runoff that is not managed properly can negatively impact the environment and wildlife.  Stormwater flows much faster down a road than it does in woods.  The faster moving water picks up pollutants and sediments that are carried to creeks and streams.  The result of this unmanaged runoff is:

  • flooding
  • sediment build-up
  • polluted streams and creeks
  • land erosion
  • uninhabitable environments for fish and other animals

It’s easy to notice flooding after large rain storms, but smaller rains also have an impact as well.  95% of rainfall volume occurs from smaller rain events.  Over time,  even with smaller volume rainstorms, streams and creeks lose their natural bends and tend to become warmer over time, decreasing the amount of dissolved oxygen which can be harmful to fish.


Bethel Park Stormwater Ordinance

US EPA MS4 Information

PADEP MS4 Information

Allegheny County Conservation District Stormwater Page

Three Rivers Wet Weather Stormwater Page



PADEP Homeowners Guide to Stormwater BMP Maintenance

PADEP – Be Stormwater Smart

Three Rivers Wet Weather Watershed Protection Guide

US EPA Stormwater Best Management Practices

Bethel Park Stormwater Word Search

Eagle Scout Inlet Marking Project