Mercer Island School District cancels Monday classes; boil water advisory remains in effect

MERCER ISLAND -- The city of Mercer Island is advising all residents to boil their water before drinking after routine tests came back showing the presence of E. coli.

On Saturday, Public Health - Seattle and King County ordered all food establishments to "suspend operations" until the boil water advisory is lifted.

The Mercer Island School District announced Sunday that all classes and activities on Monday, September 29th are canceled.

Seattle Public Utilities, the city's water provider, routinely collects 18 samples each month from the Mercer Island water distribution system. Test samples collected on September 26th came back the next day showing the presence of E. coli -- indicating the water may be unsafe to drink, officials said.

Here's information from the city of Mercer Island:

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.

To address this 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.

Aside from Mercer Island, 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.

Fecal 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, visit our website at for updates.

Or call the City of Mercer Island hotline at 206-275-7800