Mercer Island residents must restrict summer water use after pipe break

Mercer Island residents may need to conserve water this summer because of a major supply line break earlier this month. The water main leak on April 3 made the ground unstable and triggered threats of a landslide. It forced evacuations for approximately 20 homes near Mercer Island High School, which closed for a day before the area was deemed safe.

More on the Mercer Island burst pipe: Residents evacuated due to landslide risk allowed to return home

Seattle Public Utilities (SPU) owns and manages the 24-inch high-pressure water pipe, which supplies most of the water to Mercer Island. City officials said it is still out of service and a smaller backup line is currently being used, but the smaller system won’t be able to keep up with demand this summer.

“It is likely water conservation efforts will need to be enacted to manage daily demands,” the city wrote in an online post. “These may include reducing garden and lawn irrigation, running the dishwasher and washing machine only with a full load, using commercial car washes that recycle water, and reducing personal water use wherever possible.”

Initially, the estimate to fix the pipe was several days but is now projected to take much longer. SPU crews said repair work is being hampered by challenges with the site and topography. As of now, there is no official timeline for when things might be back to normal.

No mandatory water restrictions have been announced yet, but the city said those will likely happen soon.

“We know these types of restrictions can be inconvenient. While evaluation and planning work is still underway to determine what restrictions may be needed, we aim to provide you with advance notice that water conservation will likely be essential this summer,” the city wrote. “This will ensure the island’s water demand does not exceed the supply provided by the backup line and that city reservoirs will continue to meet resident needs while sustaining water quality, safety and firefighting requirements.”

On Thursday, SPU sent this statement on the leak and its steps to fix it:

Since April 3, Mercer Island and Seattle Public Utilities (SPU) have been working together to address the water main leak and determine next steps with the water supply pipeline serving Mercer Island. The 1950s pipeline, which is is owned and operated by SPU, delivers wholesale water to two City of Mercer Island water storage tanks. Mercer Island in turn owns and operates its own water distribution system, including those tanks, which provides water to the homes and businesses on the island. Essentially, SPU gets the water to Mercer Island, and the City of Mercer Island distributes the water throughout the island. SPU and Mercer Island collaborate closely on capital improvements to SPU’s pipeline.

A team of engineers, geotechnical experts, and planners has been assessing the leak and identifying viable repair options, such as lining the pipeline. While water pipeline leaks are not uncommon and SPU crews routinely repair pipes, the particular pipeline and leak are in a complicated location that make it difficult to excavate, which limit our ability to assess the cause and the range of repair options available. We are making good progress on the situation, but repair decisions are impacted by the complicated location and are taking some additional time to work through.

SPU and Mercer Island are working together and will continue to closely collaborate to select the best path forward for Mercer Island’s water customers and the community surrounding the pipeline leak location. In the meantime, SPU’s pipeline remains shut down where the leak was occurring, and water is being routed to Mercer Island’s water storage tanks via an alternative, smaller pipeline owned by Mercer Island.”

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Residents with questions or concerns are urged to contact the Mercer Island Customer Service Team by email or phone at (206) 275-7600 during operating hours.

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