SPU Water Main Leak and Repair

While the supply line is back online providing water to the Island, work at the west and east pits (where the repaired pipe was reconnected to the water system on each end) continues.

Work at the west pit (SE 40th Street and Greenbriar Lane) is almost complete. Restoration has been completed at this location and the only remaining work is to stripe the road.

At the east pit (near SE 40th Street and 97th Ave SE), SPU’s contractor is installing a back-up bypass between SPU’s transmission line and the City’s distribution system. This work is expected to last until the end of August. There will be flagged one-way traffic along SE 40th Street as the contractor completes the installation of the bypass along SE 40th Street.

City Manager Jessi Bon issued Proclamation No. 344 which ends the state of local emergencies related to the SPU water pipeline leaks and the supply of potable water to Mercer Island, respectively declared in Proclamations No. 327 and No. 329. These local emergencies are no longer necessary following the restoration of the water supply line earlier this month.

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

Repairs and quality testing have been completed for the SPU water supply line and the line has been returned to service. This means Islanders can now resume normal water use.

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

Water customers should not experience any change in water quality, safety, or pressure as part of the supply line transition. A small number of customers may experience cloudy water however this is temporary and water remains safe to use. Islanders with questions or concerns about their water service should contact the City’s Customer Service Team at 206-275-7600.

Work is in the final stages for the SPU water supply line repair and remains on track to be completed by the end of July or early August. SPU crews are now working on filling, flushing, and disinfecting the pipe before final testing can be completed. This is the last step to return the repaired line to operation!

Flushing the water system after repairs or maintenance work is necessary to ensure water quality and safety. While we’ve all been taking steps to conserve water as this repair has been underway, certain flushing events are unavoidable and you may notice them taking place as part of this project and others. City and SPU crews coordinate to ensure water flushing events are conducted only when necessary during this period of water conservation. The water used to flush the repaired SPU water supply line comes directly from SPU and does not impact the water levels in the City’s reservoirs.

Once this work is complete and the line is operational, the Island will resume having adequate incoming water supply to meet normal demand. But don’t let up just yet! We ask Islanders to keep up the good work conserving water in your homes and businesses – the Island’s reservoirs have maintained adequate levels because of your continued hard work, thank you.

Further updates will be shared here on Let's Talk.

Work is in the final stages for the SPU water supply line repair and remains on track to be completed by the end of July or early August. Once this work is complete and the line is operational, the Island will resume having adequate incoming water supply to meet normal demand. Here’s the latest update:

Over the past several weeks, crews successfully installed the 1,300 foot flexible liner and completed quality and readiness testing. Crews are now working to connect the lined section to the existing pipe on each end.

Once connected, crews will work on flushing, filling, and disinfecting the pipe which is scheduled for next week. Final testing will then be completed. This is the last step to return the repaired line to operation.

Flushing elements of the water system after repairs or maintenance work is done is necessary to ensure water quality and safety. While we’ve all been taking steps to conserve water while this repair has been underway, certain flushing events are unavoidable and you may notice them taking place as part of this project and others. City crews are coordinating to ensure water flushing events are conducted only when necessary during this period of water conservation. Upcoming water flushing includes the final stages of the SPU water supply line repair and a previously-postponed project to replace a fire hydrant on the south end of the Island.

The City has reduced municipal water use wherever possible and we ask Islanders to keep up the good work conserving water in your homes and businesses. The Island’s reservoirs have maintained adequate levels because of your continued hard work – thank you.

Additional updates will be shared next week as the final stages of the SPU water supply line repair are completed.

Good news! The flexible liner has been installed in the SPU water pipe and is expected to be fully operational by the end of July or early August after additional testing and disinfecting. However, this means our water supply is still reduced and our community needs to continue conserving water where we can. It is especially important now as temperatures rise. Please make sure you're taking steps to conserve water use.

Seattle Public Utilities and the City of Mercer Island are continuing work on the repair to the water line.

Contractors recently replaced a 40’ section of the City’s water main on SE 40th Street with ductile iron pipe, in preparation for excavating access pits for the main water line.

SPU crews will next be excavating these access pits, located on the east and west ends of the project site. These access pits allow crews to directly access the pipeline and will be used to insert and pull the liner through the pipe. All residents in the immediate area have been notified about the work and temporary impacts to traffic.

Early next week, SPU contractors will remove a large cottonwood from City property adjacent to the east access pit, near SE 40th Street and 97th Ave SE. The removal of this tree is necessary due to its location near the pit and contact with adjacent utility lines.

As early as next Wednesday, crews will begin to pull the new liner through the existing 24” pipe and work on connection fittings.

Stay tuned here on Let's Talk for additional updates.

Seattle Public Utilities (SPU) contracting crews will begin repairing the water pipe that was discovered to be leaking on April 3. The repair will consist of lining 1300 feet of the pipe with a durable material.

SPU’s contractor will begin mobilizing and staging equipment at the work sites as early as June 12. This will be followed by digging an east pit and a west pit, located at the intersection of Greenbrier Ln and SE 40th St and near 97th Ave SE on SE 40th St to allow crews to access and install the liner inside of the pipe.

Mercer Island residents can expect to experience slowed traffic through the construction areas, lane closures, as well as noise and dust from the excavation, utility trucks, and other equipment.

Crews will work Monday through Friday, from 7:00am to 5:00pm; this may include working on the Juneteenth (June 19) and Independence Day (July 4) federal holidays.

For more information, please contact SPU project manager Jade Sullivan at 206-255-8276 or Jade.Sullivan@seattle.gov.

Check out the FAQs for more information and answers to common questions.

After several weeks of close coordination and analysis, the City of Mercer Island and Seattle Public Utilities (SPU) are planning for a repair to the 24-inch water pipe that has been out of service since April 3.

A traditional repair of the pipe is challenging due to the site conditions. The location of the leak is on a very steep slope, in a difficult area to access with no adjacent roadway. As a result, SPU has proposed a liner solution that will insert a flexible liner inside the existing pipeline, spanning a total of 1,100 feet.

This approach does not require excavation on the slope. Instead, the liner will be inserted through two access points to the east and west of the leak location. When the liner is installed, it will include a leak detection system to ensure a rapid response if there is ever a subsequent issue with the pipe. Geotechnical engineers from the City and SPU have been closely evaluating the stability of the slope in considering this repair option to ensure the community’s safety.

This week, staff from SPU and outside contractors completed the excavation of the west access point. This work allowed the contractor to complete the first of two video inspections of the 24-inch pipe. SPU and the City are currently reviewing the video to learn more about the cause of the leak.

Once the City completes its review of the design, video inspection, and site reports, the repair will be scheduled for construction in early July.

If you have questions about this project, please contact the City’s Customer Service Team at 206-275-7600.