Are you ready for the New Industrial Stormwater General Permit Coming in 2025?

The Industrial Stormwater General Permit (ISGP) is an important way the Washington Department of Ecology (Ecology) regulates facilities with industrial activities that can cause stormwater pollution. The ISGP is up for renewal in 2025 – are you ready?

Key Dates To Know for ISGP Renewal

  • The current ISGP expires December 31, 2024
  • The next ISGP cycle will run from January 1, 2025 through December 31, 2029.
  • For current ISGP holders, the deadline to renew your permit is July 5, 2024 (180 days before the current permit expires).

How Do I Renew My ISGP Coverage?

Submit your ISGP renewal application via your SecureAccess Washington (SAW) account to continue coverage at your facility. See Ecology’s Permit Renewal Instructions for a step-by-step guide, and for additional help, visit Ecology’s Web Portal Help webpage.

What Changes Are Anticipated in 2025?

Based on listening sessions presented by Ecology staff in 2023, several changes to the ISGP are anticipated in the next permit cycle beginning in 2025.

  • Likely: Ecology plans to expand the scope of the ISGP permit to cover ALL transportation facilities. This will extend beyond facilities which currently trigger coverage and will include facilities performing maintenance activities, equipment cleaning operations, and airport deicing.
  • Likely: Changes to current ISGP benchmark values or effluent limits are not anticipated.
  • Likely: Corrective Actions – permittees installing engineered stormwater treatment that goes beyond off-the-shelf treatment options will automatically be granted a 1-year extension. Waivers and extension request due dates will be changed to a date beyond May 15th each year.
  • Likely: Ecology plans to remove automatic approval of Conditional No Exposure (CNE) following a 90-day period. Starting in 2025, CNE will only be approved following an Ecology site inspection and approval.
  • Likely: Ecology will provide clarity on Puget Sound Sediment Cleanup Sites (defining the locations beyond general waterbodies).
  • Likely: Training requirements will be expanded to include onsite operators beyond just staff employed by the site owner.
  • Potential: Sampling for emerging contaminants, such as 6PPD-Q and PFAS/PFOA/PFOS, is not anticipated to be required until monitoring and testing standards have been established for those contaminants.
    • However, under ISGP Special Condition section G12, Ecology may require emerging contaminant sampling under an Administrative Order at some facilities that are known contributors of these substances.
  • Potential: Ecology may be introducing a “sampling point waiver,” which would allow permittees to exclude monitoring at discharge points on several claims (including safety). The waiver process would undergo a public comment period.
  • Potential: You may be required to provide adequate facility staff training of sampling procedures to conduct sampling during ALL hours of operation.
  • Potential: Additional sweeping requirements (i.e., monthly sweeping instead of once per quarter) may be applied to specific industries (to be determined).

Herrera Is Here to Help

Herrera Environmental Consultants offers a full range of stormwater compliance services that can be tailored to your needs. From complete program support to technical support for specific elements, Herrera is here to help with your ISGP needs, including:

  • Apply for Notice of Intent (NOI) application to obtain initial permit coverage.
  • Prepare or update your Stormwater Pollution Prevention Plan (SWPPP).
  • Conduct monthly site inspections and quarterly stormwater monitoring.
  • Coordinate with the laboratory and review sampling results.
  • Submit quarterly Discharge Monitoring Reports and/or Annual Reports to Ecology.
  • Train staff for site inspections and/or stormwater sampling.
  • Assess your site and recommend improvements.
  • Level 1, 2, or 3 Corrective Action Support, and Stormwater Engineering Design for Treatment if needed.


By George Iftner