Industrial Stormwater General Permit

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.

Find the types of facilities that require coverage under the ISGP in Table 1 of the current permit.

The current permit went into effect Jan. 2, 2015, and expires Dec. 31, 2019.

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Current permit and related documents

Permit Reissuance

The current permit expires on Dec. 31, 2019. We plan to reissue an updated general permit in Nov. 2019.

What's changing:

Our proposed changes to the permit include:

  • Adding two new industry groups that require coverage.
  • Adding language to protect groundwater.
  • Changing the timing of First Flush.
  • Revising requirements for Consistent Attainment.


Public outreach and listening sessions: Fall 2018
Formal public comment period on the draft permit: Spring 2019
Issue final permit: Nov. 2019
Permit effective: Early 2020

Public outreach and listening sessions

We will hold listening sessions on the proposed changes to the ISGP. These meetings are a chance for you to learn more about the proposed changes to the permit and to ask Ecology staff any questions you have about permit coverage.

Listening sessions are scheduled for the following locations and times:

In person:
Union Gap - Sept. 25, 2018, 6:30 p.m.
Spokane - Sept. 26, 2018, 6:30 p.m.
Renton - Oct. 16, 2018, 6 p.m.
Lacey - Oct. 23, 2018, 6 p.m.
Bellingham - Oct. 24, 2018, 6 p.m.

Webinar - Oct. 3, 2018, 6:30 p.m.
Download and view the webinar (35 MB)

We will answer questions and accept informal feedback on the proposed changes until Nov. 26, 2018.

Previous permit documents

Permit applications and forms


Contacts for assistance

Central Region

For permittees located in the following counties:

Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, and Yakima

Clay Keown
Permit Administrator

Eastern Region Northwest Region Southwest Region