Stormwater Pollution

Polluted runoff is the number one threat to clean water. Stormwater picks up debris, chemicals, dirt, and other pollutants before it flows into a storm drain and then directly into the closest creek or stream. 

Though the amount of any particular pollutant might not seem like very much, when multiplied by the size of a given community, it has a very large impact on the quality of the water. 

Pollutants commonly found in stormwater runoff include:

  • Cigarette butts
  • Fertilizer
  • Grease
  • Heavy metal such as:
    • Cadmium
    • Copper
    • Lead
    • Zinc
  • Leaves and grass clippings
  • Litter
  • Motor oil
  • Pesticides
  • Pet Waste
  • Sediment

Effects of Stormwater Runoff

  • Bacteria and other pathogens from pet waste can wash into recreational areas and create serious health problems.
  • Litter such as cigarette buts, bottles, cans, and plastic items often wash into creeks and streams and can kill, suffocate, or hurt the creatures that reside there.
  • People and other animals can become sick or die from eating diseased fish or ingesting polluted water.
  • Polluted stormwater affects drinking water sources - which affects human health and increases drinking water treatment costs.
  • Stormwater runoff that has been polluted has adverse effects on plants, fish, animals, and people. Sediment clouds the water and makes it difficult for aquatic plants to grown and can even destroy aquatic habitats. 
  • Too many nutrients from fertilizers and pesticides can cause algae blooms, which, in turn, remove oxygen from the water, when the algae die. When oxygen levels are low, fish and other organisms cannot survive. 

Where Does Stormwater Pollution Go? 

When it rains, or when water is used outdoors, som of the water soaks into the ground. However, with increasing impervious surfaces, more water runs off the land, because impervious surfaces do not allow water to soak through. This is stormwater runoff, and it picks up pollutants from the ground and carries them to the nearest storm drain, drainage ditch alongside the street, creeks, and streams. Ditches and storm drains do not connect to the sanitary sewer system, so everything that flows down the drain goes directly to the nearest water body, ultimately flowing into the ocean. 


The storm drainage system is separate from the sanitary sewer system. The sanitary sewer system carries water through a water treatment plant where it is treated before it is released into a body of water. The storm drainage system doe snot include a water treatment plant. Stormwater and everything it carries with it is emptied into a body of water, without ever being treated. This is why it is vital for everyone to pay close attention and work to prevent stormwater pollution. 


*Information on this Web Page excerpted from City of Concord, Copyright 2019, and City of Winston-Salem, Copyright 2006-2020