Promontory Point Sewer Repair Project

Construction work completed

Dungeness Construction
 Corporation completed construction on the replacement sewer in the Promontory West subdivision in 2017. Site restoration wrapped up in the spring of 2018.

HDPE piping on Norway Hill

Promontory Point HDPE Sewer Piping


This project provided a permanent sanitary sewer replacement for affected homes located in Promontory Point. The previous sanitary sewer main, located along the northeast portion of the pedestrian trail near 102nd Ave NE, was damaged by landslides. A temporary lift station maintained sanitary sewer service for the affected homes until the new sewer was installed.

Northern anchor point near Chateau Retirement Communities

Promontory Point Sewer Northern Anchor

Design solutions
We contracted with HWA GeoSciences to study the geologic aspects of the landslides.  Then we hired Gray and Osborne as the City's design consultant, who proposed several design solutions. We looked closely at reliability, geotechnical concerns, maintenance, and cost. The location of the replacement sewer main minimizes ground disturbances and ties into an existing gravity-fed sewer line. 
Affected owners
The City began working with property owners in 2013 to negotiate for the property rights to acquire a utility easement.