Phase I Municipal Stormwater Permit Revised

The Washington State Department of Ecology has issued a revised Phase I Municipal Stormwater Permit that will go into effect on August 19, 2016. Developed as part of the National Pollutant Discharge Elimination System (NPDES), the Phase I permit regulates stormwater discharges from municipal separate storm sewer systems (MS4s) in incorporated cities with populations of over 100,000 and in unincorporated counties with populations greater than 250,000.

The main changes in the permit include:

  • Incorporation of municipal stormwater programs that provide equivalent or better protection of receiving waters as compared with the minimum technical requirements as stipulated in Appendix 1 of the permit.
  •  A description of the City of Seattle’s management plan for stormwater pollutants that discharge to the Lower Duwamish Waterway.

Further discussion of the changes to the Phase I permit can be found on the Department of Ecology’s website here.

If you would like to know more about stormwater management and how it applies to your community or business, contact Freer Consulting at (206) 285-9044 or [email protected].