PORTLAND, Ore. -- More samples from Portland's former primary water source have tested positive for the parasite Cryptosporidium.
On Feb. 13, the low levels of the parasite were found in Portland's primary water source and the Portland Water Bureau shifted the water supply away from the Bull Run Watershed to the Columbia South Shore Well Field.
Michael Stuhr, a water bureau administrator, said no action was required but the agency decided to make the move as a precaution. He said the recent detection of the parasite doesn't pose an increased health risk.
"After a series of very low-level detections, we are proactively activating our secondary source while we collect more data," Stuhr said, adding that the city is in compliance with the treatment variance issued by the Oregon Health Authority.
Since the water bureau made the switch, more samples from the Bull Run Watershed have tested positive for Cryptosporidium. So far, nine out of 32 samples have tested positive for the parasite.
Portland uses the Columbia South Shore Well Field as a secondary source, often during the summer, to supplement the water supply from the Bull Run. The secondary supply meets or surpasses all federal and state drinking water regulations, according to the bureau.
Stuhr said it may take as much as two weeks for the water supply shift to reach homes and businesses.
Customers with questions can call 503-823-7525.
(© 2017 KGW)