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Mercer Island Residents Again Advised to Boil Tap Water Before Drinking
All Mercer Island Restaurants are Ordered to Close.

(Mercer Island, WA) – 12:45pm, Thurs Oct 2 -- Since the health advisory was lifted last Monday (Sept 29), the City of Mercer Island has continued to monitor the quality of its drinking water. 
Test results received this morning indicate that one sample contained E. Coli, and another sample contained Total Coliform.  
As a result, the City is compelled to investigate the situation and in consultation with the state Department of Health, is issuing a second boil-water advisory.
All water customers on the Island should boil their water before drinking, or use bottled water.
There are no confirmed reports of illness at this time.
Public Health – Seattle & King County orders all restaurants to close; inspectors will be visiting all locations to provide assistance.
Boiled or purchased bottled water should be used for drinking, making ice, brushing teeth, and food preparation until further notice. Bring the water to a boil, let it boil for at least 1 minute, and let it cool before using. Boiling kills bacteria and other organisms that could potentially be in the water.
Dishwashers can be used if run with the sanitizing/heat cycle and commercial dishwashing detergent. Dishes can be hand washed if rinsed in a diluted bleach solution – one teaspoon household bleach to one gallon of water – and then allowed to air dry.
Water can be used for bathing, but do not drink any of the water and do not allow babies to put the water or wet washcloth in the mouth.
Mercer Island School District
Based on these latest test results, the Mercer Island School District is discussing the situation. Please continue to check the District’s website for updated information at
Other private schools will each make their own closure decision.
Public Health – Seattle & King County orders all 62 permitted food establishments such as restaurants, coffee shops, and delis operating on the Island to suspend operations today. Health inspectors will provide guidance and oversight for restaurants on how to operate with a modified menu should the boil-water advisory continue.  Health inspectors will be providing instructions to schools, childcare, long-term care and skilled nursing facilities on how operate during the boil-water advisory. Permitted food establishments are asked to contact Public Health-Seattle & King County.
Restaurants owners should call (206) 263-9566 for guidance.

To address the situation, City Utility crews are inspecting system facilities, flushing water mains in potential problem areas and ensuring chlorine levels are adequate throughout the distribution system.  The City of Mercer Island continues to sample the water throughout the Island to confirm the quality of the water. We will issue further notice when the water supply is confirmed to be safe.
According to SPU, all other SPU water is safe for drinking. Extensive testing over the past two days of SPU’s distribution system, which provides drinking water to much of King County, has shown that the problem is isolated to Mercer Island.  Daily routine testing continues at all municipal water systems throughout the area. Contact SPU for more information on their system.
Coliforms and E. Coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems.
Organisms in drinking water are not the only cause of such symptoms. If people experience any of these symptoms and they persist, they may want to seek medical advice. People at increased risk should seek advice about drinking water from their health care provider.
This notice is being issued following consultation with the Washington State Department of Health and Public Health – Seattle and King County.

If residents have any further questions, please contact the City of Mercer Island hotline at 206-275-7800 or visit our website at


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