Stormwater can pick up pollution from factories and businesses. Those contaminants are carried into waterways and harm fish and other aquatic life. The Industrial Stormwater General Permit (ISGP) helps industrial facilities comply with federal regulations that reduce pollution. We require most industrial sites in Washington to monitor, measure, and reduce stormwater pollution leaving their site.
The current permit went into effect on Jan. 1, 2020 and expires Dec. 31, 2024.
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For Permittees in the following cities and counties:
City of Seattle, Skagit, or Whatcom county
Thurston, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Skamania, or Wahkiakum County
Clallam, Kitsap or King County (with the exception of the City of Seattle)
San Juan, Island, Pierce, Kittitas, Yakima, Benton, or Klickitat County
Adams, Asotin, Chelan, Columbia, Douglas, Ferry, Franklin, Garfield, Grant, Lincoln, Okanogan, Pend Oreille, Snohomish, Spokane, Stevens, Walla Walla, Whatcom, Whitman, or Yakima County
Industrial Stormwater General Permit Questions: