Phase I Municipal Stormwater Permit
The Phase I Municipal Stormwater Permit regulates discharges from municipal separate storm sewer systems (MS4s) owned or operated by the state's largest cities and counties.
*Populations are based on the 1990 U.S. census.
- Incorporated cities with a population of over 100,000* people.
- Unincorporated counties with populations of more than 250,000* people.
Phase II Municipal Stormwater Permits for Eastern and Western Washington
The Phase II Municipal Stormwater Permits regulate discharges from certain "small" MS4s in Washington State.
We issue two Phase II permits:
The permit also applies to public separate storm sewer systems operated by other types of public entities located in a Phase I or II city or county. Examples include ports, prison complexes, park districts, universities, or diking and drainage districts.
Washington State Department of Transportation (WSDOT) Municipal Stormwater Permit
The WSDOT municipal stormwater permit regulates discharges from state highways, rest areas, park-and-ride lots, ferry terminals, and maintenance facilities within the urbanized areas of the state.
Who's covered under the municipal stormwater permits?
View a map of Phase I and Phase II Municipal Stormwater Permit area boundaries.
Phase II Municipal Stormwater Permit Writer
Phase I Municipal Stormwater Permit Writer
Skagit, Snohomish, and Whatcom counties, and the cities of: Anacortes, Arlington, Bellingham, Burlington, Everett, Ferndale, Granite Falls, Lake Stevens, Lynden, Marysville, Mill Creek, Monroe, Mount Vernon, Mukilteo, Oak Harbor, Sedro-Woolley, and Snohomish
The cities of: Bellevue, Bothell, Brier, Clyde Hill, Duvall, Edmonds, Issaquah, Kenmore, Kirkland, Lake Forest Park, Lynnwood, Medina, Mercer Island, Mountlake Terrace, Redmond, Sammamish, Seattle, Shoreline, Snoqualmie, and Woodinville
Kitsap and King County, and the cities of: Algona, Auburn, Bainbridge Island, Black Diamond, Bremerton, Burien, Covington, Des Moines, Federal Way, Kent, Maple Valley, Newcastle, Normandy Park, Pacific, Port Orchard, Poulsbo, Renton, SeaTac, and Tukwila
Clallam and Pierce counties, and the cities of: Bonney Lake, Buckley, Dupont, Edgewood, Enumclaw, Fife, Fircrest, Gig Harbor, Lakewood, Milton, Orting, Port Angeles, Puyallup, Steilacoom, Sumner, Tacoma, and University Place
Clark, Cowlitz, and Thurston Counties, and the cities of: Aberdeen, Battle Ground, Camas, Centralia, Kelso, Lacey, Longview, Olympia, Tumwater, Vancouver, and Washougal
Chelan, Douglas, and Yakima counties, and the cities of: East Wenatchee, Ellensburg, Kennewick, Richland, Selah, Sunnyside, Union Gap, Wenatchee, West Richland, and Yakima
Asotin, Spokane, and Walla Walla counties, and the cities of: Asotin, Clarkston, Moses Lake, Pasco, Pullman, Spokane, Spokane Valley, and Walla Walla
WSDOT Statewide Permit Writer