E. coli bacteria were found in the water supply on August 25, 2023 in the immediate area of Phantom Ranch at Grand Canyon National Park in Arizona. These bacteria can cause illness and are a particular concern for people with weakened immune systems.
Bacterial contamination can occur when increased run-off enters the drinking water source (for example, following heavy rains). It can also happen due to a break in the distribution system (pipes) or a failure in the water treatment process.
Fecal coliforms and E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, and people with severely compromised immune systems.
Currently, the only affected area is Phantom Ranch and the immediate vicinity, but visitors to the park should bring their own water or boil any water from park faucets first before drinking to kill the bacteria and other organisms in the water. This means bringing the water to a rolling boil for one minute per 1,000 feet of elevation, then letting it cool prior to using. Boiled or bottled water should be used for drinking, making ice, brushing teeth, washing dishes, and food preparation until further notice.
The park has made control system adjustments, restarted the chlorination process, and increased sampling for coliform bacteria to determine the source of the contamination. The public will be notified once the tests show no bacteria and visitors will no longer be required to boil water.