Stormwater runoff is generated when precipitation from rain and snowmelt events flows over land or impervious surfaces and does not percolate into the ground. As the runoff flows over the land or impervious surfaces (paved streets, parking lots, and building rooftops), it accumulates debris, chemicals, sediment or other pollutants that could adversely affect water quality if the runoff is discharged untreated. The primary method to control stormwater discharges is the use of best management practices (BMPs). In addition, most stormwater discharges are considered point sources and require coverage under an NPDES permit. Most states are authorized to implement the Stormwater NPDES permitting program.

The National Pollutant Discharge Elimination System (NPDES) Stormwater Program regulates stormwater discharges from three potential sources: municipal separate storm sewer systems (MS4s), construction activities, and industrial activities. Most stormwater discharges are considered point sources, and operators of these sources may be required to receive an NPDES permit before they can discharge. This permitting mechanism is designed to prevent stormwater runoff from washing harmful pollutants into local surface waters such as streams, rivers, lakes or coastal waters.

As stormwater flows over driveways, lawns, and sidewalks, it picks up debris, chemicals, dirt, and other pollutants. Stormwater can flow into a storm sewer system or directly to a lake, stream, river, wetland, or coastal water. Anything that enters a storm sewer system is discharged untreated into the waterbodies we use for swimming, fishing, and providing drinking water. Polluted runoff is the nation’s greatest threat to clean water.

Information for Homeowners and Residents

By practicing healthy household habits, homeowners can keep common pollutants like pesticides, pet waste, grass clippings, and automotive fluids off the ground and out of stormwater. Adopt these healthy household habits and help protect lakes, streams, rivers, wetlands, and coastal waters. Remember

to share the habits with your neighbors!

Healthy Household Habits for Clean Water

Vehicle and Garage

• Use a commercial car wash or wash your car on a lawn or other unpaved surface to minimize the amount of dirty, soapy water flowing into the storm drain and eventually into your local waterbody.

• Check your car, boat, motorcycle, and other machinery and equipment for leaks and spills. Make eepairs as soon as possible. Clean up spilled fluids with an absorbent material like kitty litter or sand, and don’t rinse the spills into a nearby storm drain. Remember to properly dispose of the absorbent material.

• Recycle used oil and other automotive fluids at participating service stations. Don’t dump these chemicals down the storm drain or dispose of them in your trash.

Lawn and Garden

• Use pesticides and fertilizers sparingly. When use is necessary, use these chemicals in the recommended amounts. Avoid application if the forecast calls for rain; otherwise, chemicals will be washed into your local stream.

• Select native plants and grasses that are drought- and pest-resistant. Native plants require less water, fertilizer, and pesticides.

• Sweep up yard debris, rather than hosing down areas. Compost or recycle yard waste when possible.

• Don’t overwater your lawn. Water during the cool times of the day, and don’t let water run off into the storm drain.

• Cover piles of dirt and mulch being used in landscaping projects to prevent these pollutants from blowing or washing off your yard and into local waterbodies. Vegetate bare spots in your yard to prevent soil erosion.

Home Repair and Improvement

• Before beginning an outdoor project, locate the nearest storm drains and protect them from debris and other materials.

• Sweep up and properly dispose of construction debris such as concrete and mortar.

• Use hazardous substances like paints, solvents, and cleaners in the smallest amounts possible, and follow the directions on the label. Clean up spills immediately, and dispose of the waste safely. Store substances properly to avoid leaks and spills.

• Purchase and use nontoxic, biodegradable, recycled, and recyclable products whenever possible.

• Clean paint brushes in a sink, not outdoors. Filter and reuse paint thinner when using oil-based paints.

Properly dispose of excess paints through a household hazardous waste collection program, or donate unused paint to local organizations.

• Reduce the amount of paved area and increase the amount of vegetated area in your yard. Use native plants in your landscaping to reduce the need for watering during dry periods. Consider directing downspouts away from paved surfaces onto lawns and other measures to increase infiltration and reduce polluted runoff.

Pet Care

• When walking your pet, remember to pick up the waste and dispose of it properly. Flushing pet waste is the best disposal method. Leaving pet waste on the ground increases public health risks by allowing harmful bacteria and nutrients to wash into the storm drain and eventually into local waterbodies.

Swimming Pool and Spa

• Drain your swimming pool only when a test kit does not detect chlorine levels.

• Do not drain your pool or spa into the sanitary sewer system. Discharge the water into a grassy area.

• Properly store pool and spa chemicals to prevent leaks and spills, preferably in a covered area to avoid exposure to stormwater.

Septic System Use and Maintenance

• Have your septic system inspected by a professional at least every 3 years, and have the septic tank pumped as necessary (usually every 3 to 5 years).

• Care for the septic system drainfield by not driving or parking vehicles on it. Plant only grass over and near the drainfield to avoid damage from roots.

• Flush responsibly. Flushing household chemicals like paint, pesticides, oil, and antifreeze can destroy the biological treatment taking place in the system. Other items, such as diapers, paper towels, and cat litter, can clog the septic system and potentially damage components.

Helpful Links


For Contractors:


Additional Links



Who Are You Going to Call?

Citizens can help report violations or problems they notice in their local streams before they cause more damage and pollution. Residents sometimes may be the first to recognize “illicit” discharges being directed into storm sewers or flowing out of storm sewer outfall pipes into streams. “Dry Weather Flows” (flows from outfall pipes after a 72 hour or greater period without rain) should be reported to your municipality for further investigation.

New stormwater regulations from Pennsylvania’s DEP require that your municipality investigate more thoroughly potential illicit discharges (pollutants) into our streams. You can help by promptly reporting the following events to the authorities listed in the hotline boxes below. Here are some of the conditions that you should report and to whom they should be reported.

  • Sediments leaving a construction site during rain events and other violations – Delaware County Conservation District Send Photo If Possible (Aston Township, DEP)
  • Observed pollution event or pollutants in stream (DEP)
  • Clogged or leaking sewer lines (Southwest Delaware County Municipal Authority)
  • Inadequately treated sewer effluent from treatment plant (Southwest Delaware County Municipal Authority, DEP)
  • Spills, hazardous materials (DEP Spills or PEMA hotlines)
  • Illegal dumping into water courses or storm sewers
  • Dry weather flows from outfall pipes into streams (Aston Township)
  • Fish Kills (Fish Commission, DEP)
  • Water Main Breaks (Aqua or Chester Water Authority)

Water pollution events can be reported online at the DEP website:
Select Environmental Complaints then Southeast Region

Aston Township Citizen Water Quality Hotlines

PADEP Emergency Phone: 484-250-5900

Aston Township Phone: 610-494-1636

Emergency Service – 9 1 1

DEP Water Quality Complaint Hotline Daytime 484-250-5991 Weekdays
8:30 am to 4:30 pm
DEP 24 Hour Water Quality Hotline 484-250-5900 Anytime, including Evenings & Weekends
Spills & Other Emergencies Hotlines PA DEP 484-250-5990 PA Emergency Mgmt. Agency 1-800-424-7362
Off site discharge of Sediment, erosion & Other improper controls during construction Chest Co. Conservation District 610-925-4920

Del. Co. Conservation District 810-892-9484

Send Photo, Full Address & Directions
Clogged or leaking Sanitary sewer lines;
Sewage smell in creek
Southwest Delaware County Municipal Authority
After Hours: Call 911
Fish Kills; Illegal Fishing PA Fish Commission
Also call DEP Water Quality 484-250-5900
Dry Weather Outfall Flows Aston Township
8:00 am to 4:30 pm
Broken Water Mains Chester Water Auth. 24 Hrs, 7 days
Broken Water Mains Aqua PA 24 Hrs, 7 days