Skip to main content
King County Logo
Feb
13

Elliott West Wet Weather Treatment Station upgrade

King County is planning to upgrade the Elliott West Wet Weather Treatment Station (EWWTS). The upgrade will ensure compliance with stricter environmental regulations, meet the demands of a growing population, and handle a changing climate.

Project description

An aerial view of the Elliott West Wet Weather Treatment Facility.

The Elliott West Wet Weather Treatment Station (EWWTS) is a combined sewer overflow (CSO) facility that was first completed in 2005. Since then, it has stored and treated sewage and stormwater during periods of heavy rain. EWWTS now needs to be upgraded to meet stricter environmental standards and to adapt to changing climate.

This project will ensure that the upgraded facility meets its permit requirements. This is a major investment to ensure King County continues to protect public health and the environment for years to come.

More information about the upgrade plans will be available this summer and fall. To stay updated, subscribe to our email list.

Project update

February 12, 2025

Loud Maintenance Work at Elliott West Facility

The Wastewater Treatment Division (WTD) is conducting maintenance effort at the Elliott West CSO facility.

  • Timeline: Thursday, February 13
  • Work Hours: 7:00 a.m. - 8:00 p.m. 

Maintenance crews will be working on a cathodic protection station near the facility. A cathodic protection station monitors corrosion within pipes.

Crews will need to use vactoring (vacuuming) truck to perform part of the work. Vactor trucks are loud but required to remove water from the area and allow the work to take place.

Vactor truck work will begin at 9:00 a.m. and last three to five hours.

Additional vehicles and equipment will also be at the facility to assist with the work.

Please provide crews space to complete the work. This will help keep everyone safe and reduce possible delays in the work.

WTD understands that this work can be disruptive to local residents. We thank you for your patience.

For project updates, join our email list.

Project schedule

The project schedule spans from 2023 to 2032. Design 2023-2027, and Construction 2027-2032. Community Outreach occurs the entire duration.

Our team is in the early stages of designing the needed upgrades to EWWTS. Project timelines may change due to a number of factors. We will provide updates as our work progresses and any schedule changes are needed.

Project location

expand_less