Portland residents relying on the Bull Run Watershed for their tap water might want to keep an ear to the ground as the Portland Water Bureau reports low but consistent traces of Cryptosporidium in the drinking water. According to a recent update from the City of Portland, the potentially harmful microorganism was found in water samples collected on December 30 and December 31, 2025, with two Cryptosporidium oocysts detected in each of the 50 liters sampled.
While these detections follow closely on the heels of a previous find on December 29, public health officials have assessed the situation, and currently, there are no immediate steps customers need to take. This does not negate the fact, however, that Cryptosporidium can lead to cryptosporidiosis, an illness characterized by symptoms such as diarrhea, vomiting, fever, and stomach pain which in generally healthy people usually resolves without intervention but poses a significant threat to those with compromised immune systems like people with AIDS, inherited immune diseases or those taking immunosuppressive drugs due to cancer or organ transplants.
The Portland Water Bureau, which does not currently treat the water for this particular pathogen, plans to establish filtration by September 30, 2027, as part of an agreement with the Oregon Health Authority. In the interim, they’re doubling down on watershed protection and increasing monitoring efforts to safeguard public health. “Customers who are immunocompromised and receive their drinking water from the Bull Run Watershed,” advises the Environmental Protection Agency, “consult with their healthcare professional about the safety of drinking the tap water,” according to the City of Portland…