SPU Water Main Leak and Repair

On April 3, 2024, the City of Mercer Island learned of a leaking underground Seattle Public Utilities (SPU) water pipe. The leak created unstable soil conditions, which could have resulted in dangerous flooding if the soil were to move substantially and break the water line, putting homes at risk. After a geotechnical engineer reviewed the soil conditions, the City notified residents in approximately 20 homes near 95th Court SE to evacuate their property.

All affected residents were allowed back in their homes after City and SPU crews were able to reduce or eliminate flows in the two water mains adjacent to the unstable slope, mitigating the risk of property damage if either water main were to break. The City declared an emergency and activated its Emergency Operations Center while plans for a repair were developed.

Mercer Island’s water system received water from a smaller backup supply line for 120 days while emergency work was underway to repair a leak in the main pipe. During this time of reduced water supply, the community successfully curtailed water use to maintain adequate levels in the Island’s reservoirs.

On August 1, the City confirmed that repairs and quality testing have been completed for the SPU water supply line and the line had been returned to service. This means Islanders can now resume normal water use. Final restoration work at the two access pits continues throughout August and September.

Learn more about the leak and repair work here.

The City sincerely thanks our residents and businesses for their hard work throughout this emergency.