Ecology NPDES Permit

Mill Creek's Surface Water Utility (SWU) operates under a permit issued by the Washington State Department of Ecology called the National Pollutant Discharge Elimination System (NPDES) Phase 2 municipal stormwater permit. The NPDES permit is primarily based on the Federal Clean Water Act, but also the Endangered Species Act for protection of salmon habitat.

Clean Water Act
The Clean Water Act requires municipal agencies across the United States to take steps toward reducing polluted stormwater runoff. The law was applied in two phases:

  • Phase 1 was for larger agencies with a population over 100,000
  • Phase 2 was for agencies under 100,000

Mill Creek is a Phase 2 agency, and the Phase 2 permit for western Washington covers approximately 80 cities and portions of 5 counties. The updated permit became effective August 1, 2013, and will expire in 2018.

Permit Coverages
The permit covers a wide range of required activities, including operation and maintenance, education and outreach, illicit discharge detection, and enforcing development standards. A new Phase 2 permit will take effect on August 1, 2013, with new requirements on items such as implementing Low Impact Development (LID) facilities.

Surface Water Management Program
One of the permit requirements is to post the city's Surface Water Management Program (SWMP) document and the annual report for public review. The SWMP is designed to reduce the discharge of pollutants and meet water quality requirements to the maximum extent practicable, and is updated every spring for submittal with the city's Annual Report to Ecology.

The public is welcome to review the relevant documents and make comments regarding the SWMP. Comments can be made by contacting the Public Works and Development Services department at 425-551-7254.