Four restaurants on Mercer Island have been cleared to reopen Friday, serving limited menus of prepackaged foods that don’t require water. Several more may get the go-ahead later in the day, said Sharon Bogan, of Public Health – Seattle and King County.
The boil-water alert instituted Thursday remains in effect for the island’s 23,000 residents. But test results from water samples collected on Thursday showed none of the E. coli contamination picked up earlier in the week, officials announced Friday.
At least two days of clean results are necessary before the alert can be lifted, said city spokesman Ross Freeman. And officials want to be sure they’ve fixed the problem for good before taking that action.
“We’re in a detective-work phase,” he said. “Unfortunately, we cannot at this point give a date when we know the alert can be lifted.”
Working with Seattle Public Utilities, the city boosted the chlorine level in its water-storage tanks and has expanded water sampling to include some private residences and other places where bacteria might have entered the water system.
The city wants to hear from homeowners whose garden-irrigation systems may not be equipped with backflow preventers and assured them that there would be no penalty for speaking up.
It’s possible that contaminated water from a hose or hydraulic pump could have been sucked into the water system during periods when water pressure dropped, Freeman said. So far, though, there’s no evidence of any pressure drops since E. coli bacteria were first detected in the water system last week, he added.
Free water is available for vulnerable residents at the Community Center.
The next round of test results will be available by noon Saturday.
Sunday’s Mercer Island Farmers Market will open as usual.