Cryptosporidium Detected from the Bull Run Intake: May 7 and May 8, 2024
In the 50 liters of water sampled each day from May 5 to May 8, the Portland Water Bureau detected one Cryptosporidium oocyst in each of the samples collected on May 7 and May 8. Cryptosporidium oocysts are a potential disease-causing microorganism. Prior to this detection, Cryptosporidium was last detected from the Bull Run Watershed intake on April 22, 2024.
Exposure to Cryptosporidium can cause cryptosporidiosis, a serious illness. Symptoms can include diarrhea, vomiting, fever, and stomach pain.
- People with healthy immune systems recover without medical treatment.
The Environmental Protection Agency (EPA) has estimated that a small percentage of the population could experience gastro-intestinal illness from Cryptosporidium and advises that customers who are immunocompromised and receive their drinking water from the Bull Run Watershed consult with their healthcare professional about the safety of drinking the tap water.
The State has determined that the general public does not need to take additional protections at this time.
The City of Portland will continue increased sampling four times per week until there are at least three weeks without any detections.
TVWD uses multiple water sources, of which the Portland Water Bureau provides about 70% of the blend, including water from the Columbia Shore Well Field in the summer months. In 2026, TVWD will switch to a fully filtered water source when our new Willamette Water Supply System (WWSS) and state of the art treatment plant are brought online and integrated into the TVWD system. After 2026, TVWD will no longer receive water from the Portland Water Bureau.
Learn more about cryptosporidium from the Portland Water Bureau.
