Screen Shot 2016-05-26 at 4.51.32 PMA Citizen’s Guide to Identifying & Preventing Stormwater Pollution


Stormwater runoff is water from rain or melting snow that does not soak into the ground. It flows from rooftops, over paved areas, bare soil, and sloped lawns. Municipal storm sewer systems– storm drain inlets, pipes and ditches – collect stormwater runoff and convey it directly to local bodies of water.

Ideally, the stormwater runoff is contaminant free. In reality, it picks up pollutants such as soil, animal waste, salt, pesticides, fertilizers, oil and grease, and debris and transports them to waterways where they are discharged with no treatment. This is stormwater pollution.

During rainfall, storm drains convey water from impermeable surfaces such as city streets through a series of ditches and pipes to a natural outlet, such as a stream or river. The stormwater systems in place do not have the capability to clean or filter contaminants.

The “Illicit Discharge”

An illicit discharge is any discharge to a municipal storm sewer system that is not composed entirely of stormwater. Pollutants end up in storm sewer systems in a number of ways, many of which are easily preventable. In some instances, companies and individuals have waste pipes tapped into stormwater pipes. In other cases, individuals use the storm drain inlets to dispose of various types of waste. Disposal of anything other than stormwater in storm sewers is illegal.

It is important to remember that municipal storm sewer systems are not set up to treat or process anything and exist solely to transport rain water to surrounding rivers, streams, and other bodies of water.

Examples of Illicit Discharges

  • Sewage
  • Laundry Wastewater
  • Improper Waste Oil Disposal
  • Improper Disposal of Household / Commercial /
  • Industrial Hazardous Waste
  • Seepage from Septic Tanks
  • Radiator Flushing Waste
  • Spills from Roadway Accidents

Signs of Illicit Discharge

The point in a storm sewer system where flow is discharged into a body of water is a storm sewer outfall. It may be a pipe or ditch. If the outfall is flowing when there has been no recent rainfall, this may indicate an illicit discharge. Visible sewage waste, foul odor, suds or other evidence of contamination, are indicators that an illicit discharge is contaminating the storm sewer system.

Things You Can Do to Protect Water Quality

  • Never dump anything down storm drains
  • Use fertilizers sparingly; sweep up any excessfrom driveways, sidewalks and roads
  • Avoid pesticides; learn about Integrated Pest Management (IPM)
  • Pick up after your pet
  • Direct downspouts onto grassy areas away from paved surfaces
  • Check vehicles for leaks
  • Wash vehicles on grass instead of on the driveway, or take your car to the car wash
  • Dispose of household waste properly


Click here to download the WNY Stormwater Coalition’s brochure.