E.coli found in portion of city water system, but retests came back safe
By LEE HUGHES
Staff reporter
MEDICAL LAKE — About 131 Medical Lake residents received disturbing news in late July when city maintenance crews went door-to-door distributing notices that routine water samples had tested positive for the presence of E.coli bacteria.
The notice advised residents to use bottled water or boil tap water for one minute until further notice.
While additional samples were drawn and submitted for testing the same day and came back without any signs of E.coli, it gave city officials a scare.
“It was my worst nightmare,” Scott Duncan, Medical Lake maintenance supervisor, said at the time.
The initial notice was issued earlier than required by state law.
It takes 18 hours for bacteria from samples to grow and indicate the presence of E.coli bacteria in lab receives samples, after which officials have 24 hours to issue a PUBLIC NOTICE, according to state health officials.
But that’s the mandatory minimum.
Once the city was notified of the initially unsatisfactory test results, and after some internal discussion, Medical Lake officials decided to issue the boil order right away rather than wait for results from a second test out of an abundance of caution and concern.
“If I lived here I would want to know,” Duncan, who lives just outside city limits, had said.
The testing standard for the presence if E.coli is zero, according to state officials. Testing frequency for a city the size of Medical Lake is six samples per month.
Operators are required to collect at least three new samples for a retest — one from the same location as the original sample, plus one sample each from upstream and downstream — once E.coli is found in a municipal water system.
Medical Lake collected nine samples, Duncan said, three times more than required, in an effort to isolate every potential contamination source.
All nine tests came back negative for E.coli.
“That was one of the best phone calls you can get,” Duncan, who was clearly relieved that the situation turned out as it did, said at the time.
Lee Hughes can be reached at [email protected].
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