Pollution Sources

As rainfall lands on the surface of the ground, two things happen, either the water soaks into the ground, or it runs off the surface, flowing down hill along with the other runoff. As stormwater runoff flows toward our rivers and streams, it encounters different surfaces and materials, and sometime picks up substances and takes it along for the ride. This is how stormwater pollution occurs, and the following information is presented so that you may understand how stormwater gets polluted, and how you can help prevent this.

Common Contributors to Stormwater Pollution:
The following sources commonly contribute to stormwater pollution. They have been broken down into three general categories, to show that we all can contribute to stormwater pollution whether at home, or at work, without even realizing it.

Residential Sources:
  • Bacteria, parasites, and nutrients from pet wastes and faulty septic systems
  • Vehicle fluids such as oil, gas, and antifreeze
  • Improper disposal of old paint, pesticides, solvents and batteries
  • Street litter such as Styrofoam, plastic, paper, and cigarette butts
  • Yard waste such as grass clippings, tree trimmings, and leaves
  • Overuse of fertilizers
Commercial & Industrial Sources:
  • Chemical spills, uncovered or unprotected outdoor storage and unprotected waste storage areas
  • Washing vehicles or equipment on paved surfaces where the dirt and soap is rinsed into storm sewers, or nearby streams
  • Uncovered fueling stations and unprotected fuel storage tanks
  • Improper storage of hazardous materials (i.e., a lack of secondary containment basins around storage areas)
  • Discharge of process or waste liquids to anywhere that is not designed or capable of handling these fluids
Construction Sites:
  • Sediments and other debris that washes off site during rain events may clog fish gills, damage fish habitat, and block the light needed for plants to survive
  • Improper disposal of wash water from concrete and mortar mixers
  • Uncovered storage for oils, solvents and other hazardous fluids
  • Performing vehicle maintenance and lubrication at improper places on-site
  • Porta-potties placed near streams or creeks, where spillage cannot be detained