Sewer lakeline blockage affecting some Mercer Island properties

Published 11:30 am Tuesday, February 24, 2026

This morning, the city of Mercer Island informed residents that a sewer lakeline blockage has occurred and is affecting north Mercer Island properties from Luther Burbank Park to 97th Avenue Northeast.

In an urgent advisory, the city issued this request at 11 a.m. to affected property owners: “Please immediately stop any activities that result in wastewater discharge, including running washing machines and dishwashers, and taking showers/baths. Try to minimize toilet flushing.”

The blockage occurred in the underwater sewer lakeline between Pump Station 10 and Pump Station 11. The city said that every gallon of wastewater discharged from the above activities fills the limited capacity remaining in the sewer pipes serving these properties. With no current outlet, the wastewater is being “held” in those sewer lines with nowhere to go and may begin backing up into homes.

Impacted Islanders’ water is safe to drink since the water distribution system is not affected or tied to the sewer system.

Islanders experiencing a sewer issue can call the city’s customer service team at 206-275-7600. For a list of affected addresses and the city’s response, visit: https://orlo.uk/FCAeb