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New Industrial Stormwater General Permit Coming Soon

The Industrial Stormwater General Permit (ISGP) for Washington is set to be reissued in 2025. This reissuance process occurs every 5 years and often brings changes and new challenges that permittees must face. In this article, we will break down what you need to know to gear up for the new permit in 2025.

Listening Sessions

Ecology will host 5 listening sessions to kick off the permit reissuance process in September 2023. During these sessions, Ecology will discuss their drafted plans for the new permit. This is your chance to get a handle on proposed changes and to share your thoughts and concerns in an informal setting. Your feedback during this phase is invaluable, as it can help shape the direction of the new permit and ensure that your operational realities are considered.

Register for Listening Sessions 

Formal Comment Period

Building on the insights from the listening sessions, Ecology will release a formal draft of the new permit. This is expected to occur in the summer of 2024. This will initiate a public comment period that offers a more structured platform for feedback. During this stage, all comments received will be considered and formally addressed by Ecology. Your participation in this process is pivotal, as your observations, suggestions, and concerns can directly influence the final version of the permit.

Duty to Reapply

It is important to remember that as a part of the current ISGP, permittees have a duty to reapply a minimum of 180 days before the current permit expires on December 31, 2024. This will put the reapplication deadline sometime around the July 4th holiday in 2024. This process The Washington Stormwater Center will be sending out more guidance, and will be happy to assist with this reapplication process as the deadline gets closer.

Finalization and Implementation

Ecology will review, consider, and respond to all public comments and use these to finalize the new permit before January 1, 2025. While it is currently unclear what (if any) changes will be implemented within the new permit, The Washington Stormwater Center will be available to help permittees understand and comply with any new regulations.


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Also included in this issue: 9 Tips to Survive the “First Flush”