Stormwater runoff from construction sites can carry muddy water, debris, and chemicals into local waterways. Sediments, chemicals, and debris can harm aquatic life and reduce water quality.
We require regulated construction sites to get coverage under the Construction Stormwater General Permit (CSWGP). Following the requirements in this permit helps control and reduce water pollution. If water on your construction site is contaminated see this guidance for contaminated water on construction sites.
Operators of regulated construction sites are required to:
- Develop stormwater pollution prevention plans.
- Implement sediment, erosion, and pollution prevention control measures.
- Obtain coverage under this permit.
The current modified permit went into effect May 5, 2017, and expires Dec. 31, 2020.
To receive updates about this permit, sign up for our listserv
For Permittees in the following cities and counties:
Adams, Asotin, Benton, Chelan, Columbia, Douglas, Ferry, Franklin, Garfield, Grant, Island, King (except for the cities of Seattle and Kent), Kittitas, Klickitat, Lincoln, Okanogan, Pend Oreille, San Juan, Skagit, Snohomish, Spokane, Stevens, Walla Walla, Whatcom, Whitman, or Yakima County
City of Seattle, City of Kent; Kitsap, Pierce, or Thurston County
Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Skamania, or Wahkiakum County
Construction Stormwater General Permit Questions