The State of Oregon Health Authority's Drinking Water Program has required the City of Portland to issue a Boil Water Notice for all Portland Water Bureau customers and some regional water providers.
Until further notice, all Portland Water Bureau customers and those in the affected areas should boil all tap water used for drinking, food preparation, tooth brushing and ice for at least one minute. Ice or any beverages prepared with un-boiled tap water on or after May 20 should be discarded. Detailed maps, fact sheets and additional information can be found on the Water Bureau's website at www.portlandoregon.gov/water/boilwaternotice or by calling Customer Service at 503-823-7770.
In three separate incidents from May 20 to May 23, repeat water samples confirmed the presence of total coliform and E. coli in routine drinking water samples. The water samples that tested positive for bacteria were collected at the outlets of Mt. Tabor Reservoirs 1 and 5, and at the SE 2nd Avenue and Salmon Street water sampling station. Both reservoirs have been taken offline.
All Portland Water Bureau customers are affected. Also affected are customers of the following water providers:
- Burlington Water District
- City of Gresham (North of I-84)
- Lake Grove Water District
- Lorna Portland Water
- Palatine Hill Water District
- Rockwood Water District
- Tigard Water Service Area (including Durham, King City and Bull Mountain)
- Valley View Water District
- West Slope Water District
"While we believe at this time that the potential health risk is relatively small, we take any contamination seriously and are taking every precaution to protect public health," said Portland Water Bureau Administrator David Shaff.
Consuming boiled and bottled water will ensure public health protection until the Water Bureau can determine that the water system is clean of contamination through surveillance sampling. Customers will be notified when they no longer have to boil their water. The Portland Water Bureau is working with the Multnomah County Health Department to provide health-related information to the public.
"The chance of any health problems related to this water test result is low. If any problems occur, we would expect diarrhea," said Dr. Paul Lewis, Interim Tri-County Health Officer. "We monitor cases of bacterial diarrhea and will be aware of any increase following this event."
The Portland Water Bureau collects approximately 240 routine bacterial samples per month throughout the system. The test to determine the presence of bacteria takes about 18 hours. It is not unusual for one of these samples to test positive for bacteria. Samples to confirm possible contamination are collected immediately after an initial detection of the presence of bacteria in drinking water. Once the detection has been confirmed, public health officials recommend that the public boil all tap water before consuming.
Contamination can occur when there is a loss of water pressure, a pipe breaks, or conditions that expose drinking water to outside elements. The Portland Water Bureau is performing a full investigation to identify the cause of the contamination. However, it is not always possible to make an exact determination.