Bull Run Watershed Tests Positive For Cryptosporidium: Multnomah County

PORTLAND, OR — Portland Water Bureau officials on Wednesday announced the Bull Run Watershed has once again tested positive for Cryptosporidium, a parasitic and potentially disease-causing microorganism. According to bureau officials, the sample that tested positive was drawn from the watershed on Sept. 24.

A 10-liter sample was found to contain one Cryptosporidium oocyst, officials said, noting that there is no need for the general population to take precautionary measures before drinking water — though people with severely weakened immune systems are encouraged to seek guidance from their primary care provider.

"At this time, the bureau and public health partners at Multnomah County continue to believe Bull Run water is safe to drink," Portland Water Bureau Administrator Michael Stuhr said in a statement. "We will continue to monitor for Cryptosporidium, protect the watershed, notify the public, and work with our health partners to make the best decisions for public health."

Patch previously reported one out of five Bull Run Watershed samples tested between March 12 and March 17 turned up positive for Cryptosporidium, though officials said the water was still safe to drink at that time as well.

This is the first Cryptosporidium detection since March, officials said. The Water Bureau has tested for Cryptosporidium since the Oregon Health Authority (OHA) imposed that requirement in 2012, though the Water Bureau has requested exceptions to the requirement since that time.

Based on EPA and OHA guidelines, the requirement could be lifted if "a specified water treatment technique is not necessary to protect the public health based on the nature of the raw water source for a public water system."

The Portland City Council on Aug. 2 instructed the Water Bureau to develop a plan for constructing a filtration plant that would specifically meet Cryptosporidium treatment requirements, county officials said. That plan is expected to be delivered to the OHA by Oct. 11.

The OHA earlier this year told the bureau the requirement to test for Cryptosporidium would be ended no later than Nov. 22, officials said.

"We continually monitor for human illness caused by Cryptosporidium," Multnomah County Health Officer Dr. Paul Lewis said in a statement. "But since past detections of Cryptosporidium oocysts in Bull Run water have not been associated with an increase in human disease, I do not expect it to be different this time."

The Bull Run Watershed reportedly serves more than 1 million people in Multnomah, Clackamas, and Washington counties, not including tourists and other visitors to the metro region.

To follow the bureau's Cryptosporidium tests, visit the "Cryptosporidium Treatment Variance Monitoring Results" website.

Water customers with questions about water quality or Cryptosporidium testing can call 503-823-7525.

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