Parasite Found in Portland Drinking Water

Cryptosporidium can cause disease, especially in those with weakened immune systems

A disease-causing parasite has been found in Portland’s drinking water. Portland Water Bureau Director Mike Stuhr said it’s the first positive result since last March. Multiple water samples with Cryptosporidium from earlier this year led to the city’s decision to build a water filtration plant. The Water Bureau will present a schedule for the treatment plant to the Oregon Health Authority (OHA) next month.

From January to March the Portland Water Bureau had 19 water samples test positive for Cryptosporidium. A sample taken Sunday has once again detected the disease-causing microorganism.

The Portland Water Bureau has monitored for Cryptosporidium under conditions of a variance for the treatment of Cryptosporidium issued by its regulators at OHA. As a result of the detections earlier this year, OHA informed the Portland Water Bureau that the variance from treating for Cryptosporidium would be revoked no later than Nov. 22, 2017. On Aug. 2, City Council directed the bureau to construct a water filtration plant to meet the Cryptosporidium treatment requirements. The Portland Water Bureau will submit a schedule for construction of a filtration plant and ongoing measures to continue to protect public health to OHA by Oct. 11.

“At this time, the bureau and public health partners at Multnomah County continue to believe Bull Run water is safe to drink,” said Portland Water Bureau Administrator Michael Stuhr. “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.”

As always, the bureau recommends that people with severely weakened immune systems seek specific advice from their health care providers about drinking water. There is no need for the general public to take additional precautions.

“We continually monitor for human illness caused by Cryptosporidium 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,” said Multnomah County Health Officer Dr. Paul Lewis.

The bureau will continue to sample the Bull Run for Cryptosporidium; gather information about these detections; and notify its regulators, health officials and the public of any additional detections.

The public and the media are encouraged to view all sampling results posted to the City’s website. Customers with questions regarding water quality can call the Water Line at 503.823.7525.

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