The Portland Water Bureau announced Saturday morning its boil water order has been lifted. The order affected 670,000 customers in the Portland metro area.
Customers can use tap water again. But before using tap water for the first time, people should run the tap for at least two minutes to flush out contaminants. Or, customers can run the tap until the water runs cold.
The bureau issued the boil water order Friday after 3 samples tested positive for E. coli. Water Bureau Administrator David Shaff said test results Saturday morning showed the system was clean.
"We got the results back from a little over 60 different water samples that were taken throughout our service area and the service area of the wholesale customers that were affected, all of which came back clean, negative for bacteria," he said.
The order was lifted for customers of the Portland Water Bureau and Burlington, City of Gresham(North of I-84), Lake Grove, Lorna Portland Water, Palatine Hill, Rockwood, Tigard Water Service Area (including Durham, King City and Bull Mountain), Valley View, and West Slope Water Districts were affected.
The bureau is draining and cleaning Reservoirs 1 and 5, and will look for any indication about where the contamination came from, as it drains the reservoirs. Shaff says the bureau has reviewed surveillance video from Mt. Tabor, but that didn't reveal anything.
"In all likelihood, it comes from an animal. That is one of our vulnerabilities. It could be from a bird that's in the reservoir, flying over the reservoir, it could be from a raccoon. It could be from a domestic pet, or a small mouse or a rat. We don't know," he said, adding that the bureau may never know the source of the contamination.
Shaff says people should always remember to keep a supply of bottled water at home to be prepared in case of an earthquake or other disaster.
This story originally appeared on Oregon Public Broadcasting.