The Portland Water Bureau says tests show two samples of the E. coli found in Portland's water were not from a particularly virulent strain of bacteria. That's the 0157:H7 strain that has been associated in the past with food-borne illness, from contaminated hamburger, for example.
The Portland Water Bureau is still waiting for test results from another sample, said Water Bureau spokeswoman Jaymee Cuti.
Last week, water in reservoirs one and five tested positive for E. coli bacteria. The city issued a boil water notice for around 670,000 people in the Portland area. The notice was lifted Saturday morning. Cuti says the bureau would still have issued the boil water order, even if it had known that the E. coli was not the strain associated with food-borne illness.
The bureau is draining water out of two of the city's reservoirs.
The two reservoirs will be cleaned and refilled. Both should be back up and running by the end of this week.
Cuti says crews have emptied 9 million gallons of water from Reservoir One into the sewer system and started cleaning it Monday.
The bureau will divert 33 million gallons of water in Reservoir Five to another reservoir that isn't used for drinking water.
An earlier version of this story misreported the name of the E.coli strain associated in the past with food-borne illness. The correct name of that strain is 0157:H7.
This story originally appeared on Oregon Public Broadcasting.