PORTLAND -- The Portland Water Bureau has lifted its boil water alert after issuing a city-wide notice due to E. coli contamination.
The alert was lifted at 11 a.m. Saturday.
"Follow-up testing of drinking water has shown the absence of bacterial contamination," said Tim Hall, spokesman for the water bureau.
Hall recommended flushing all taps for two minutes, or until the water runs cold, before drinking the water.
"This will flush any potentially contaminated water from the plumbing," he said.
The city issued a 'boil water alert' Friday morning for the entire water district after the city detected E. coli in water samples.
At a press conference at noon Friday, Water Bureau Director David Shaff said this was the largest boil water alert in the city's history, impacting some 670,000 water customers.
The city recommended leaving water a full rolling boil, for over a minute, before using it.
The source of the contamination was Mount Tabor reservoirs 1 and 5. The alert includes the city of Portland, but also the cities of Tigard, King City, parts of Gresham and other districts.
"Until further notice, all Portland Water Bureau customers and those in the affected areas should boil all tap water used for drinking, food preparation, tooth brushing and ice for at least one minute. Ice or any beverages prepared with un-boiled tap water on or after May 20 should be discarded," the alert read.
"In three separate incidents from May 20 to May 23, repeat water samples confirmed the presence of total coliform and E. coli in routine drinking water samples," Shaff said.
Tri-County Health Officer Dr. Paul Lewis said the E. coli came from animal fecal matter. The most likely symptom from people drinking contaminated water would be diarrhea. Lewis said that he did not believe many people would be impacted.
Officials said that the issue would be cleared up in 24 hours.
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The city tests water in the system about 240 times a month. In addition to the Mount Tabor Reservoirs, contaminated water was found at the Southeast 2nd Avenue and Salmon Street water sampling station, according to the city.
Reservoir 5 was the center of controversy in April when the city declared it would flush 38 million gallons of water into the sewers after a teenager allegedly urinated in the water.
The city sampled the water on Tuesday. The sample tested positive for E. coli the following day. Continued tests triggered a mandatory alert, officials said.
The Centers for Disease Control and Prevention advise that people should boil tap water even if it is filtered. Most kitchen and other household water filters typically do not remove bacteria or viruses.
Medical experts told KGW on Friday that E. coli can take up to two days to incubate in someone, and symptons may not show up immediately.
Doctor John Heiser, an emergency room physician at Providence St. Vincent’s Medical Center, said the elderly, young children and people with chronic illnesses were most at risk.
The symptoms from e-coli infection include: nausea, vomiting, diarrhea, abdominal pain, or cramps.
“It’s usually no more than a 24 hour illness,” Heiser said. “Even if someone get this illness, they should be able to get rid of it on their own."
Contamination can occur when there is a loss of water pressure, a pipe break, or conditions that expose drinking water to outside elements, the city said.
For more information, water users can call the Portland Water Bureau customer service at 503-823-7770.
Mark Hanrahan contributed to this report