There is a storm drainage system within the City’s approximate thirty-three miles of streets.

Stormwater is rain and snow melt that runs off rooftops, paved streets, highways, and parking lots. As it runs off, it picks up pollution like oil, fertilizers, pesticides, soil, trash, and animal manure. Most stormwater is not treated, even when it goes into a street drain. It flows downstream directly into streams, lakes, and marine waters.

Stormwater runoff is the leading threat to our urban waters, streambeds, banks, and habitats.


Why does stormwater runoff matter?

As the population grows, urban development increases. This means more people, more developed land, and an increase in stormwater runoff and pollution to Washington’s waters.

Unmanaged stormwater runoff can:

  • Damage salmon habitat.
  • Contribute to flooding and drought.
  • Contaminate swimming areas.
  • Contaminate the groundwater you drink.
  • Degrade water quality.




Stormwater management plan  Stormwater Management Program (SWMP)