North Mercer Island/Enatai sewer upgrade
Installed during the 1970’s, the county’s North Mercer Island and Enatai sewer pipelines are aging and reaching capacity. Increasing sewer capacity will allow King County to provide reliable wastewater service through the year 2060.
During the planning phase, the project team identifies and evaluates locations for a new pipeline. We always include the existing location as an option because this alignment has proven itself in operations. In this case, where a pipeline is located in the water, we look for additional options to move it upland.
The project team evaluates options using a range of factors: technical, constructability, operations and maintenance, environmental, permitting and property acquisition, community, cost, and risk.