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Project update

February 16, 2018

Pipe pullback scheduled to start as early as Wednesday, Feb. 21: 16-24 hours of nonstop weather-dependent work

King County’s contractor has will soon begin the final step in the Horizontal Directional Drilling (HDD) process – pipe pullback, a process that installs the pipe by pulling it east to west through a pre-drilled underground pathway.

  • Beginning as early as this weekend, crews will straighten out the pipe on the lake
  • As early as 7 a.m. on Wednesday, Feb. 21, crews plan to begin the pipe installation process

Crews must install the pipe without stopping and will work round-the-clock for an estimated 16-24 hours, including overnight hours. If unforeseen events require more than 24 hours of work, we will notify project neighbors via email.

The pullback schedule is weather-dependent and subject to change. We will send the most up-to-date information via email.

Please don’t hesitate to contact us during pullback on our 24-hour construction hotline at 206-296-7800. 

View project update for more information.

Work area map

work area map

Learn more: view project FAQs (updated December 2017).

Boater information

Boater information: pipe staging activities on Lake Sammamish , December 6, 2017

Caution - large pipe in water. Boaters use caution in SW Lake Sammamish near Vasa Park.


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Project description

The Sunset and Heathfield Pump Stations and related sewer pipes send sewage from Sammamish, Issaquah, and Bellevue to be cleaned at King County’s treatment plant in Renton. This sewer system has provided reliable service for around 50 years and is reaching its limit.

This project will upgrade both pump stations and the connected force main pipe. The project will also upgrade the Eastgate Trunk structure near I-90. The Eastgate Trunk connects the force main pipe to a larger pipe, carrying flows to be treated at the South Treatment Plant in Renton. The improved system will help serve the growing population for many years.

Read our December 2016 newsletter for more information about how community feedback influenced final design and for details about upgrades to the pump stations

Sunset Pump Station upgrades

Sunset Pump Station Final Design

  • Four new pumps to increase capacity
  • New electrical and controls systems
  • New standby generator allowing the station to continue operating during power outages
  • New heating and air conditioning systems (HVAC)
  • Addition of native plans and restoration of shoreline habitat
  • Roof replacement and added green roof to manage stormwater
  • New lighting and fencing
  • Permeable driveway

Heathfield Pump Station upgrades

Heathfield Pump Station Final Design

  • New lighting and fencing
  • Four new pumps to increase capacity
  • New electrical and controls systems
  • New standby generator
  • New heating and air conditioning systems (HVAC)
  • Rain garden
  • Landscaping
  • Roof replacement

Project area

Project schedule

Construction is expected to start as early as summer 2017 and end in 2020.

1707_Sunset_Heathfield_construction-schedule_800View high-resolution version .

Project location

Project locator map for Sunset and Heathfield pump stations and force main upgrade

Back to the capital projects overview map .

Heathfield Pump Station,
3541 163rd Ave. S.E., Bellevue

Sunset Pump Station,
3730 W. Lake Sammamish Pkwy. S.E., Bellevue