City of Prescott shuts down two airport-area water wells over presence of potentially harmful chemicals
Wells were taken offline immediately with no interruption of service; no immediate health risk

(City of Prescott/Courtesy)

(City of Prescott/Courtesy)

As of about 2 p.m. Friday, July 8, two of the City of Prescott’s eight domestic water wells were shut down because of the presence in the water of two man-made chemicals that are thought to be harmful to human health.

At about 6 p.m. Friday, the city sent out a news release alerting the public to the situation. Prescott Community Outreach Manager John Heiney said the city learned of the presence of the chemicals in its two wells near the Prescott Regional Airport at about 2 p.m. Friday and immediately stopped water production at the two water wells.

The chemicals that were found in the water are Perfluoriooctanoic acid (PFOA) and Perfluorooctane sulfonate (PFOS), according to the city news release.

“While PFOA and PFOS are not currently regulated by the U.S. Environmental Protection Agency (EPA) nor the Arizona Department of Environmental Quality (ADEQ), emerging scientific thought is that these compounds may be harmful to human health,” the news release stated.

Results of sampling for the two airport-area wells showed levels of PFOA as high as 15 parts per trillion (ppt) and PFOS as high as 12 ppt, which is greater than the temporary advisory levels given by the EPA and ADEQ.

The recommended Health Advisory Levels (HALs) of 0.004 ppt for PFOA and 0.02 ppt for PFOS, according to the information from the city.

City officials will promptly investigate the source of the chemicals, Heiney said, noting that more information is expected to be released on Monday, July 11.

Meanwhile, the city says that using city water does not pose a risk. “There is no immediate health risk,” the news release states. “You do not need to use an alternative water supply since the affected wells are no longer in use. However, if you have specific concerns, please consult your doctor.”

The affected wells will not be put back into service until they meet the recommended Heath Advisory Levels established by the EPA and ADEQ.

The news release noted that the City of Prescott tests its drinking water supply regularly to ensure that it meets all drinking water quality standards and that recent test results had found the presence of the two chemicals.

In explanation of the chemicals, the news release stated, “PFAS such as PFOA and PFOS are a group of manufactured chemicals that have been used in industry and consumer products since the 1940s because of their useful properties. PFAS can be present in our water, soil, air, and food as well as in materials found in our homes or workplaces. PFAS can break down very slowly and can build up in people, animals, and the environment over time.”

According to online sources such as, products made with PFOA include stain-resistance carpet, water-repellent clothes, paper and cardboard packaging, ski wax, and foams used to fight fires.

Heiney said the testing did not find presence of chemicals in the water from the city’s other six wells.

“The City operates a total of 8 wells located in and around Prescott,” the news release said, adding that there would be no noticeable difference in water delivery to any customers.

More information about PFOA or PFOS is available on the city website at or by contacting City of Prescott Public Works Department – Water Division at 928-777-1118.

Information about the EPA Health Advisory and ADEQ actions is available at the Arizona Department of Environmental Quality (ADEQ) at, and the Environmental Protection Agency (EPA) at

Information provided by the City of Prescott.

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