Frequently Asked Questions about detections for Cryptosporidium in the Bull Run
Yes, the Portland Water Bureau monitors for Cryptosporidium at the Bull Run drinking water intake at least two days per week. If Cryptosporidium is detected, monitoring is increased to four days per week as long as detections continue.
The Portland Water Bureau (PWB) does not currently treat for Cryptosporidium, but is working to install a new filtration plant by September 2027 under a compliance schedule with Oregon Health Authority (OHA). This long-term investment will remove the microorganism Cryptosporidium, make Portland’s system more reliable, and provide consistent, excellent water to customers.
Planning for the filtration plant began in 2017 and takes approximately 10 years to plan, design, and construct. Meanwhile, PWB is implementing interim measures such as watershed protection and additional monitoring. PWB is working with its public health partners to continue to protect public health.
At this time, the PWB and public health partners at Multnomah County continue to believe Bull Run water is safe to drink. To ensure public health protection until filtration is installed, the Portland Water Bureau is taking interim measures that include watershed protection, monitoring for Cryptosporidium, public notification and coordination with public health officials. As always, PWB recommends that people with severely weakened immune systems seek specific advice from their health care providers about drinking water. At this time there is no need for the general public to take additional precautions.
While the general public does not need to take additional precautions for Cryptosporidium, people with compromised immune systems may wish to take additional precautions such as:
- Safe commercially bottled water: Water labeled with any of the following messages has been processed by a method effective against Cryptosporidium: reverse osmosis, distilled, filtered through an absolute 1 micron or smaller filter, or "One micron absolute".
- Boiling water before consuming: Boiling is the best extra measure to ensure that your water is free of Cryptosporidium and other germs. Heating water at a rolling boil for 1-minute kills Cryptosporidium and other microbes. After the boiled water cools, put it in a clean bottle or pitcher with a lid and store it in the refrigerator. Use the water for drinking, cooking, or making ice.
- Filtering your tap water: Many, but not all, available home water filters remove Cryptosporidium. Filters that have the words "reverse osmosis" on the label protect against Cryptosporidium, as do filters with "absolute 1 micron." Also look for the words "cyst reduction" or "cyst removal" for a tested filter that works against Cryptosporidium. The wording should indicate that the filter is listed and labeled to NSF/ANSI standard 53 or 58 by an ANSI accredited certification organization.
- Using a Home distiller: You can remove Cryptosporidium and other microorganisms from your water with a home distiller. If you use one, you need to carefully store your water. After purification, put the water in a clean bottle or pitcher with a lid and store it in the refrigerator.
Fortunately, the Bull Run watershed is free of the sources of Cryptosporidium most commonly associated with disease outbreaks such as livestock and human sewage. Wildlife is the most likely source of Cryptosporidium in the Bull Run. Heavy rains in the watershed can increase the chances of Cryptosporidium moving from animal scat into water. However, detections can also occur in dry weather if an animal carrying the parasite deposits waste in or near the water.
The Portland Water Bureau posts all results to the website as they are received. Additionally, PWB notifies the media and interested customers of these detections. Customers can sign-up for notifications at www.portlandoregon.gov/water/cryptoupdate.