Disease-Causing Parasite Detected In Portland Water Supply

The Portland Water Bureau announced on Friday that routine monitoring of the city’s water supply has revealed low levels of a disease-causing parasite. The microorganism, known as Cryptosporidium, was detected during the week as part of regular monitoring efforts. However, public health officials have assured residents that no additional precautions are necessary at this time.

The Bull Run watershed serves as Portland’s primary source of drinking water. Since 2017, the city has been monitoring the water for Cryptosporidium due to the lack of treatment facilities for the organism. While the Portland Water Bureau is required to treat for Cryptosporidium, it is currently not equipped to do so. As a result, the city has been working alongside the Oregon Health Authority to install a filter system by 2027. In the meantime, interim measures are being implemented to protect the water source, and routine monitoring is being conducted to ensure public health.

During the sampling period from May 5 to May 8, one Cryptosporidium oocyst was detected in each of the samples collected on May 7 and May 8. However, no Cryptosporidium was found in the samples collected on May 5 and May 6. The last time Cryptosporidium was detected in the Bull Run Watershed intake was on April 22.

Cryptosporidium is known to cause symptoms such as diarrhea, vomiting, fever, and stomach pain. Individuals with severely weakened immune systems are at a higher risk of experiencing more severe illness. The Environmental Protection Agency advises individuals who are immunocompromised and rely on drinking water from the Bull Run Watershed to consult with their healthcare professionals regarding the safety of tap water consumption.

Several water districts, including the Portland Water Bureau, Burlington, City of Gresham, City of Sandy, City of Tualatin, Green Valley, GNR, Hideaway Hills, Lake Grove, Lorna Domestic Water, Lusted, Palatine Hill, Pleasant Home, Raleigh, Rockwood, Skyview Acres, Tualatin Valley, Two Rivers, Valley View, and West Slope Water Districts, receive all or part of their drinking water supply from the Bull Run watershed.