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Wastewater Treatment

King County, Washington

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: 206-477-5371
Fax: 206-684-1741
Telecommunication device for the deaf (TTY): 711

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Staff Contacts

North Beach outfall assessment

April 2013 Update – Outfall survey and repair work begins week of April 22
King County is continuing maintenance and repair work on the North Beach Pump Station outfall. On April 22 and 26, the County’s contractors will conduct marine and land surveys of the outfall alignment. In late April-May, a diving contractor will repair holes in the outfall pipeline (PDF).


A project team is assessing the condition and looking at repair/replacement options for outfall #48a. This outfall is used to discharge combined sewer overflows (CSOs) from the pump station. CSOs occur when stormwater fills the sewer pipes beyond system capacity; discharge through an outfall prevents potential for backups onto streets and into homes and businesses.

A project team is evaluating the condition and temporary repair options for outfall #48a, which was installed as part of the North Beach Sewer District Treatment Plant that once provided wastewater service to the area. This outfall, which is visible at low tide, has visible holes and sedimentation of the pipe that may limit the discharge capacity. A secondary outfall (#48b) also serves the North Beach Pump Station to prevent potential backups; however, location of the discharge point from this outfall on a recreational beach makes outfall #48a the preferred discharge location.

North Beach Outfalls #48a and #48b
  North Beach Pump Station outfall (#48a)
North Beach Pump Station outfall (#48a)

King County is currently working on longer term solutions to address the outfall, and will work with the community as those solutions are identified. We are also working to reduce CSOs from the North Beach Pump Station to meet current standards for no more than one per year on a long term average. For more information, visit the North Beach CSO Control Project.

Related project and maintenance activity