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The 2021 Stormwater Management Program (SWMP) Plan outlines King County's proposed actions to comply with the 2019-2024 National Pollutant Discharge Elimination System (NPDES) Phase I Municipal Stormwater Permit issued by the Washington State Department of Ecology.

The 2021 Stormwater Management Program Plan is offered in Adobe Acrobat format. For help using Acrobat, please visit our Acrobat help page.

Download current document here:

Please let us know your feedback to help shape the plan Comments submitted after March 31 will be considered for next year’s program plan.

Previous SWMP Plans:

For questions about the King County Stormwater Management Program, please contact us via Email.