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 Washington's urban waters, streambeds, banks, and habitats.
Why does stormwater runoff matter?
As the population grows in Washington, 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.
Pollute shellfish beds.
Contaminate the groundwater you drink.
Degrade water quality.
The state of Washington and the Washington Department of Ecology were granted delegated authority by the EPA to administer their own “State-Specific” National Pollutant Discharge Elimination System (NPDES) Permitting Program for wastewater and stormwater discharges associated with construction activity, industrial activity as well as Municipal Separate Storm Sewer System (MS4) activity. Because the EPA and The Clean Water Act (CWA) required a program for addressing the pollution caused by stormwater discharges, the Department of Ecology instituted the Water Quality Program (WQP) which administrates all of Washington’s clean water initiatives.
What types of permits are there?
The federal Clean Water Act's National Pollutant Discharge Elimination System (NPDES) has various permitting requirements based on different types of pollution discharges.
Both NPDES and State Waste Discharge stormwater general permits aim to control pollution discharges to water. For more information, see stormwater general permits.