Storm Sewer System

Tredyffrin's storm sewer (or drainage) system in the roadways keeps stormwater runoff from flooding roadways and damaging properties. There are 3 typical components:

• Collection: Inlets are spaced along a roadway, with most located at low points to most efficiently collect stormwater runoff from properties and streets. Tredyffrin maintains over 3,600 inlets.
• Conveyance: Inlets are interconnected by piping, which convey stormwater to a water source. Tredyffrin maintains 59 miles of storm sewer pipes.
• Discharge: Stormwater is discharged from the pipes into local streams. Eventually all of Tredyffrin's stormwater runoff ends up in the Schuylkill or Delaware Rivers.

Tredyffrin's system is a "separate" storm sewer system (or "MS4"). It is called "separate" because stormwater is not combined with sewage in the system. The sanitary sewer system is a completely different system.

Residents may help themselves by insuring that inlets near their homes are free and clear of leaves and other debris prior to a rain storm. If an inlet is clogged and not accepting runoff, please contact the Public Works Department at (610) 408-3620 or publicworks@tredyffin.org.

NPDES MS4 Permit

Tredyffrin is required to get a National Pollutant Discharge Elimination System (NPDES) permit from the PA Department of Environmental Protection (DEP) to discharge water from our Municipal Separate Storm Sewer System (MS4)) into “waters of the Commonwealth”. The NPDES program attempts to reduce the quantity of pollutants that stormwater carries into storm sewer systems and ultimately discharges into waterways.
There are 6 required minimum control measures that Tredyffrin reports to DEP about:

• Public education and outreach
• Public participation and involvement
• Illicit discharge detection and elimination
• Construction site runoff control
• Post-construction runoff control
• Pollution prevention and good housekeeping

Reducing stormwater runoff and pollutants

Stormwater management regulations are triggered when development, construction or grading is proposed on a property. The regulations are intended to reduce the volume and rate of stormwater runoff that drains into streams (via the storm sewer system, as well as basins, swales and other controls) and improve water quality by filtering pollutants from runoff through infiltration of the water into the ground. Proper control of the rate, volume and quality of stormwater protects creeks from erosion and pollution, reduces sediment accumulation and protects property from the effects of flooding.

Regulations that require controls to reduce the volume of stormwater (for example, through green roofs) and require infiltration are fairly new. Most properties in Tredyffrin were developed before they were in place. As a result, much of the runoff in Tredyffrin goes through the Township's storm sewer system and is discharged unfiltered into the streams.

There are many things property owners can due to reduce the volume and improve the quality of stormwater that discharges into creeks. Click here for ideas.

If you have a complaint about stormwater, erosion, or sedimentation, please fill out the Complaint Form and submit it to Erin McPherson by email or call (610) 408-3617.