Cryptosporidium Detected from the Bull Run Intake: April 22, 2024

Laboratory Testing Water Quality

In the 50 liters sampled each day from April 21 to April 24, 2024, the Portland Water Bureau detected one Cryptosporidium oocyst in the sample collected on April 22, 2024. Cryptosporidium oocysts are a potential disease-causing microorganism. Prior to this detection, Cryptosporidium was last detected from the Bull Run Watershed intake on April 3, 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.

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Fall Photos of Bull Run Reservoir
Fall colors on the road to Bull Run Reservoir
Bull Run Watershed with trees in fall colors