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Environmental review
This page lists environmental documents prepared by the King County Wastewater Treatment Division that are currently available for public review and comment.
Documents currently available for public comment
Title of proposal: Elliott West Wet Weather Treatment Station
Description of proposal: The King County Wastewater Treatment Division proposes to upgrade the existing Elliott West Wet Weather Treatment Station (EWWTS) to achieve more reliable compliance with King County’s National Pollutant Discharge Elimination System permit. The project includes expansion of the existing facility onto the property directly to the south, and decommissioning the existing dechlorination system at the Denny Way Regulator Station. If it is determined that additional improvements are necessary to ensure water quality compliance, the Elliott West CSO Outfall may also be modified.
Location of proposal, including street address, if any: The project is located at the existing EWWTS property at 601 Elliott Avenue W, Seattle WA, 98119. The project includes expansion of the facility onto the King County-owned parcel to the south at 531 Elliott Avenue W. The Denny Way Regulator Station is located in Myrtle Edwards Park at 3155 Alaskan Way, about 0.5 mile south of the EWWTS site. The 96-inch-wide Elliott West CSO Outfall (#027b) is also located at the Denny Way Regulator Station and extends offshore approximately 500 feet and terminates below the mean lower low water level at a depth of -60 feet.
Issue date: June 20, 2025
Comment deadline: July 7, 2025
Submit comments via email to: WTDSEPA@kingcounty.gov; or via postal mail to:
Jacob Sheppard Supervisor, Environmental Planning, King County Wastewater Treatment Division
201 S Jackson Street, MS KSC-NR-6200, Seattle, WA 98104-3855
For questions or information on how to submit comments electronically, contact Jessica Conquest, AICP, Environmental Planner, at 206- 263-3721or jconquest@kingcounty.gov.
Download documents: Determination of Nonsignificance (DNS) and Environmental Checklist.
Frequently asked questions
The listed documents are mainly threshold determinations and checklists prepared under the Washington State Environmental Policy Act (SEPA statute, RCW 43.21C; SEPA Rules, WAC 197-11). Other environmental documents prepared by the Wastewater Treatment Division, such as documents prepared under the National Environmental Policy Act (NEPA), may also be listed.
Local, state and federal regulations mandate the ways in which agencies must notify the public that environmental documents are available for public comment. These may include mailings, signs and/or newspaper notices. The Wastewater Treatment Division typically makes the documents available in local libraries and upon request. This web page is another way in which the division provides notice and copies of these documents.
You may view and download an electronic copy of each listed document by clicking on the associated link. Information on how to provide comments on each document listed below is included in the document.
Yes. Please refer to the SEPA appeal process.