Water Emergency Lifted - Resume Normal Water Use

UPDATE | 7:00am, April 22, 2023 

Early this morning, April 22, water levels in the Island’s reservoir tanks surpassed 20 feet. This means there is sufficient water in the reservoir tanks to safely support the Island’s water needs and all Islanders can resume normal water usage.  

Water quality and safety continue to meet all standards and Islanders should not notice any changes to their water service as normal use resumes. 

This emergency has been difficult for everyone in our community and the City greatly appreciates your water conservation efforts. Together, Islanders reduced water use to low levels and helped the City successfully avoid a Precautionary Boil Water Notice and a much worse situation.  

The City will work with Seattle Public Utilities to understand exactly why this emergency resulted and identify what steps the agency can take to avoid an emergency like this in the future.  

We plan to share a comprehensive recap of this situation with the community, including photos and videos showing the immense work it took to successfully repair the Island’s water supply line. The City’s emergency management team will also work through an after-action evaluation process to identify opportunities to improve or modify the response in the future.  

Once again, the City thanks the many community members, volunteers, partner agencies, and staff that have responded to this emergency. 

For questions and to report any water issues at your home or place of business, contact the City’s Customer Service team at (206) 275-7600 or customerservice@mercerisland.gov. 

Update: The Emergency Proclamation has been lifted. 

UPDATE | 2:00pm, April 21, 2023

After Seattle Public Utilities crews completed the emergency repair to the Island’s water supply line and water quality was tested to ensure safety yesterday, water has been flowing into the Island’s reservoir tanks overnight and water levels have risen above critical thresholds. A Precautionary Boil Water Notice has successfully been avoided.  

Islanders are asked to continue conserving water where possible. This will allow the Island’s reservoir tanks to refill and prevent water levels from dropping back down below critical thresholds. It is anticipated that the tanks will reach safe levels early tomorrow morning, which would allow a return to normal water usage. Here’s why, and how the system works: 

The Seattle Public Utilities supply line provides the Island’s reservoir tanks with 3,000 - 4,000 gallons of water per minute. Under normal operations, the reservoir tanks are full and provide the Island’s water system with the supply needed during peak demand, which can exceed 4,000 gallons per minute at this time of year. When demand drops overnight, water provided by the SPU supply line makes up for water use during the day and refills the reservoir tanks.  

Currently, the reservoir tanks are playing catch-up due to the water supply emergency this week. Continuing to conserve water will allow the water coming in from the supply line to meet current demands and refill the reservoir tanks at a faster rate. Although the reservoir tanks are filling, they are still below safe thresholds and additional water is needed to allow a return to normal water use and operations.  

Islanders have done a tremendous job conserving water so far, which has allowed the tanks to refill faster than originally anticipated. Staff are currently anticipating exceeding safe thresholds in the reservoir tanks tomorrow morning.  

City staff are closely monitoring the reservoir tank levels and will alert Islanders as soon as it’s possible to resume normal water usage. Your hard work is greatly appreciated and is getting our community closer to a return to normal. 

The City thanks the many community members, volunteers, partner agencies, and staff that have responded to this emergency. 

For questions and to report any water issues at your home or place of business, contact the City’s Customer Service team at (206) 275-7600 or customerservice@mercerisland.gov.

We will continue to share updates as they are available. 

Continue scrolling for previous updates and information.

UPDATE | 6:00pm, April 20, 2023

Earlier today, Seattle Public Utilities crews completed the emergency repair to the Island’s water supply line and resolved an issue with another valve that had malfunctioned. The water supply line has since been flushed and water has been tested to confirm it meets quality and safety standards. Incoming water is now beginning to refill the Island’s reservoir tanks. 

Please continue conserving water. While water is now flowing into the reservoir tanks, it will take up to 48 hours to refill these tanks back to normal operating levels. The more water Islanders conserve, the faster our water system can return to normal operations. We will provide another update to the community on Friday, April 21, as to the status of the reservoir recovery.  Tips on maximizing water conservation are available on the City Website.

We greatly appreciate the community’s patience and quick action to conserve water during this emergency. This has been a tremendous strain for all Islanders and your collective efforts were critical in preventing a much worse emergency. 

We will continue to share updates as they are available. 

UPDATE | 1:00pm, April 20, 2023

Seattle Public Utilities crews completed the emergency repair to the Island’s water supply line and resolved an issue with another valve that malfunctioned early this morning. However, water is not yet supplying Mercer Island - the supply line must first be recharged and tested for water quality and safety. It is imperative that Islanders continue to conserve water. We will alert the Island when a timeline for service restoration is available. 

City Manager Jessi Bon, Chief of Operations Jason Kintner, and other City staff will host a Zoom webinar at 1:30pm today, Thursday, April 20 to share more about the current situation. Use this Zoom link to join: https://us02web.zoom.us/j/86465233104?pwd=TTBYaFVjTXdqVmV6RXluUm0ySzRrUT09

The webinar recording will also be available to watch anytime once it concludes.

We will continue to share updates as they are available. 

UPDATE | 5:45am, April 20, 2023

Seattle Public Utilities crews made progress on the emergency repair to Mercer Island’s water supply line overnight and into this morning, April 20. Water service to the Island’s supply line is anticipated to be restored by late afternoon.   

Islanders’ water conservation efforts have helped maintain critical water supply and pressure, meaning a Precautionary Boil Water Notice has not yet been necessary. At this time, it is anticipated that water service will be restored to the Island before water levels and pressure drop to the point where a Precautionary Boil Water Notice would be required, but we still need your help. 

Please continue conserving water to help avoid a Precautionary Boil Water Notice. We will only be able to avoid a Precautionary Boil Water Notice if Islanders continue to strictly conserve water throughout the day.  

We will provide another update as soon as the repair is complete. Please know that once the repair is complete, it will still be several hours before the City begins receiving water and we are currently estimating late afternoon today, April 20, for restoration of water supply service to the Island. We greatly appreciate the community’s patience and quick action to conserve water during this emergency and ask you to continue those efforts throughout the day. Your hard work allowed us to maintain critical water pressure and stave off a Precautionary Boil Water Notice. 

For questions and to report any water issues at your home or place of business, contact the City’s Customer Service team at (206) 275-7600 or customerservice@mercerisland.gov. 

UPDATE | 7:15pm, April 19, 2023

City leadership hosted a webinar for the community earlier this evening covering the situation - you can watch the recording online.

UPDATE | 5:00pm, April 19, 2023

Seattle Public Utilities has informed the City that a repair to the water supply lines cannot be completed until tomorrow morning (Thursday, April 20). This means the Island’s water system will only be supplied by the two reservoir tanks until that time. In response, the City has issued an emergency proclamation.

Please continue to conserve water. All Island residents and businesses are asked to reduce water to essential needs only.

If reservoir water levels drop to a certain point, a Precautionary Boil Water Notice is anticipated. The timing for Precautionary Boil Water Notice is currently anticipated for later tonight.

Join City Manager Jessi Bon, Chief of Operations Jason Kintner and other City staff for a Zoom webinar at 6:30pm tonight, Wednesday, April 19 to learn more about the water supply situation. Use this Zoom link to join: https://us02web.zoom.us/j/89112307641?pwd=V3F0T2ZMY3IvakxWbkpOLzczSmhLdz09

Here’s why this is an emergency:

Normally, the Island’s reservoir tanks contain enough water to supply Mercer Island for several days when needed. However, the Island has already been operating from these reservoir tanks for the past 65 hours due to Seattle Public Utilities’ previously scheduled work on their supply lines to the Island. SPU crews encountered a seized valve when attempting to reconnect these supply lines at the end of this maintenance work yesterday, meaning the Island’s water system must continue to rely on the reservoir tanks until that valve can be replaced and the water supply can be reconnected.

As water use continues and the reservoir tanks drop to lower levels, water pressure across Mercer Island will likely drop. If water pressure drops low enough, water quality and safety cannot be guaranteed and a Precautionary Boil Water Notice becomes necessary. Islanders will receive an Emergency Alert and updates will be shared if a Precautionary Boil Water Notice is issued.

By conserving as much water as possible, Islanders can help keep enough water in the reservoir tanks to maintain pressure. Please continue to minimize water use until further notice.

The City is working closely with our regional emergency partners to maintain essential services and is in close consultation with Department of Health water safety experts. The Mercer Island Fire Department and partner fire agencies have coordinated and implemented a comprehensive plan to ensure we have the necessary resources on island to continue to provide Fire and emergency medical services without disruption, which includes providing specialized apparatus and doubling our current on-island staffing. Our Emergency Management team will also be activating the Island’s emergency well for an additional local source of water.

Food service establishments (restaurants, schools, groceries, hotels that serve food, etc) should review Health Department's webpage for operating under a boil water advisory.

Islanders may want to consider alternate accommodations off-Island while work continues to restore full water service. The City is in constant communication with Seattle Public Utilities to keep the community informed.

Additional updates will be shared as they are available.

April 19, 2023 – During planned construction work on the supply lines that provide water to Mercer Island, Seattle Public Utilities encountered an unexpected problem and Mercer Island is currently not being supplied with incoming water. The Island’s water system is currently operating from reservoir tanks and all Islanders are asked to conserve water as much as possible until further notice.  

By conserving water, you’ll help maintain supply in these tanks to keep the Island’s water infrastructure safe and functioning. Seattle Public Utilities is conducting emergency repair work to fix the supply lines and reconnect the Island’s main water supply as quickly as possible.  

Currently, there is no impact on water quality or safety. The City’s emergency response partners are aware and extra crews will be on Island until the water lines are back up and running. Water conservation by all Islanders and businesses is critical to maintaining the stability of the system during this time. 

Ask questions and report any water issues at your home or place of business by calling the City’s Customer Service team: (206) 275-7600. 

The City will issue updates and alert all Islanders once Seattle Public Utilities completes the repair and the water system returns to normal operations.