King County Stormwater Management Program Annual Reports

Our Phase I Municipal Stormwater National Pollutant Discharge Elimination System (NPDES) Permit (Phase I Permit) requires us to submit an Annual Report to the Washington State Department of Ecology (Ecology). The Annual Report is submitted on or before March 31st and provides information for our previous year’s work.

The Stormwater Management Plan (SWMP), also attached to the Annual Report, provides our plan for complying with the Phase I Permit for the year to come.

Our Stormwater Planning program informs and assists in the development of policies and strategies to protect stormwater, which is described in our Stormwater Action Management Plan (SMAP).

You are invited to participate in the decision-making processes involving the development, implementation, and update of our Stormwater Management Plan (SWMP) and Stormwater Action Plan (SMAP). If you have questions or feedback about our Annual Report, SWMP, or SMAP please email us at stormwater@kingcountygov.

Annual Reports:

• 2021 Annual Report (24.3 MB)
• 2020 Annual Report (9.7 MB)
• 2019 Annual Report (9.8 MB)
• 2018 Annual Report (9.4 MB)
• 2017 Annual Report (9.9 MB)
• 2016 Annual Report (8.5 MB)
• 2015 Annual Report (8.4 MB)
• 2014 Annual Report (3.1 MB)
• 2013 Stormwater Monitoring Report (2.4 MB) and King County Stormwater Monitoring S8.D QAPP (12.5 MB)