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Project update - December 29, 2021

King County’s contractor continues to work inside both pump stations and outside on landscape restoration.

Crews plan to replace a generator at the Heathfield pump station . The timing for the work is dependent on the availability and delivery of the equipment. as well as weather. The replacement generator may arrive and be installed as early as Monday, January 3. Crews will need to use a crane to deliver the generator and there will likely be more noise and traffic near the station while they install and test the generator.

The Heathfield Pump Station is powered by Puget Sound Electric (PSE). If utility power is lost, the backup generators automatically activate to maintain operations and prevent a sewage overflow.

Making projects sustainable, resilient, and equitable (WTD Blog)

King County’s Wastewater Treatment Division (WTD) is being recognized for its commitment to sustainable communities and the environment. WTD’s Sunset / Heathfield Pump Stations and force main upgrade project was awarded an Envision® Silver Award this month for project sustainability. This is the second Envision-certified project for the region’s wastewater utility.


Contact us

Contact Caryn Sengupta, community services lead at:

206-296-7800 Project Hotline: please leave a message and we will return your call on the next business day.
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If you’d like to receive email or text updates on the Sunset and Heathfield pump stations and force main upgrade:

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.

Map displaying the location of the Sunset Pump Station (on short of Lake Sammamish) and Heathfield Pump Station (located west and up the hill from Sunset Pump Station) and the forcemain (pipeline) from the Sunset Pump Station to the Heathfield Pump Station)

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

  • 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 plants and restoration of shoreline habitat
  • Roof replacement and added green roof to manage stormwater
  • New lighting and fencing

Heathfield Pump Station upgrades

  • 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)
  • Landscaping
  • Roof replacement

Project schedule

Crews will work to restore SE 35th Pl and 164th Pl SE in early 2020.

Pump Station work will continue into 2021.

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