Managing stormwater from state highways

The Washington State Department of Transportation (WSDOT) manages stormwater runoff from paved surfaces like highways, rest areas, park-and-ride lots, ferry terminals, and maintenance facilities in urban areas throughout the state. In spring 2019, the Washington State Department of Ecology issued WSDOT a Municipal Stormwater Permit that regulates stormwater runoff from these paved surfaces. WSDOT prepared the 2020 SWMPP to describe how the agency will implement the 2019 permit’s requirements.

WSDOT invites you to provide feedback on the 2020 Stormwater Management Program Plan (SWMPP) (pdf 556 kb).

Email feedback to the Stormwater Permit Program Manager,, or mail it to:

           Stormwater Permit Program
           PO Box 47332
           Olympia, WA 98504-7332

WSDOT will consider all comments it receives by October 1, 2021, before finalizing the 2021 plan.

Visit the Water resources and erosion control webpage for more information on stormwater policies, procedures, and reports.