Construction work progresses near the Interbay Pump Station

King County, Washington sent this bulletin at 11/26/2025 12:30 PM PST
King County WTD Interbay Sewer and Odor Control Upgrade Project banner

November 2025

Progress update: bypass pipe installation nearing completion 

Crews have finished installing the temporary bypass pipe between the Interbay Athletic Field and Magnolia Bridge. The 5000 feet of new above-ground pipe will keep sewage flowing as crews complete underground repairs of the existing sewer pipes.

A long black pipe being lifted by an excavator near a train yard.

Crews installing the temporary bypass pipe.

The bypass pipe was installed to divert wastewater flow around the section of sewer that is being repaired.  Completion of this pipe will allow crews to begin replacing the force main at the Interbay Pump Station. A force main is a pressurized sewer pipe that carries wastewater uphill from a sewer pump. Replacing the force main will ensure that wastewater continues to travel to the County’s regional West Point Treatment Plan in Magnolia from the pump station. Replacement of the force main is scheduled to be completed by fall of 2026, and rehabilitation of the gravity line is scheduled for fall of 2027. 

Interior of a wastewater pump station showing turquoise centrifugal pumps connected to heavy-duty pipes and instrumentation.

High-capacity pumps inside Interbay Pump Station facility help keep our sewer system running safely and reliably. 

What to expect

  • Parking Impacts: Parking availability may be limited during this work. Please note that access to dumpsters will remain open for businesses and delivery access will be maintained.  
  • Equipment and Service Vehicles: Expect construction vehicles and service trucks in the area.  
  • Approved work hours are 6 a.m. to 4 p.m. Monday to Thursday.  
    • We will provide advance notice of any weekend or after-hours work. 
  • Noise, dust, and vibrations typical of an active construction project. 
  • Construction schedules can change due to site conditions, weather, and material availability. Please visit our project website for updates 

During construction, access will be maintained for all emergency vehicles, garbage, recycling, composting, and mail services. If services are interrupted, please call the project hotline at 425-595-3452.

Please watch for equipment and crews in the area, maintain slow speeds to stay safe, and follow directions from crews.

ALTERNATE FORMATS AVAILABLE

425-595-3452 OR TTY RELAY: 711 

Connect with us!

For more information or to schedule a meeting, please contact the community services team at 425-595-3452 or Interbaysewer@kingcounty.gov 

Visit the project website at: kingcounty.gov/InterbaySewer

Los servicios de interpretación y traducción están disponibles para usted sin costo alguno. Si los necesita, comuníquese con Interbaysewer@kingcounty.gov, 425-595-3452.