For questions about the Wastewater Treatment Division website, please send an e-mail message or contact us at:

King Street Center
201 S. Jackson St., Suite 500
Seattle, WA 98104-3855
Phone: 206-684-1280
Fax: 206-684-1741
Telecommunication device for the deaf (TTY): 711

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Staff Contacts
Puget Sound shoreline next to the West Point Treatment Plant, Seattle

Storage – retaining flows during large storms to prevent CSOs; following the storm event, flows are sent for treatment

Store Peak Flows
View handout (PDF file)

Store excess flows in tanks, tunnels or pipelines. Once the storm passes, slowly convey flows to an existing treatment plant.

Key considerations

  • All flow is sent to the existing West Point Treatment Plant or the Carkeek and Alki CSO Plants for treatment
  • Technology is proven and reliable
  • Finished facility is primarily underground and attractively landscaped
  • Sufficient space required for siting and constructing the facility
  • Heavy equipment needed during construction