City of Prescott Provides Monthly PFAS Test Results

Since the Arizona Department of Environmental Quality (ADEQ) identified PFAS chemicals, including PFOS and PFOA, in city potable water wells in July 2022, the City of Prescott has made, and continues to make, operational changes to the city’s potable water system to ensure that Prescott water customers receive adequate supplies of safe, clean drinking water. In order to accomplish this objective, city staff have taken monthly samples of all potable water supply wells and sent them to a certified laboratory for testing of PFOS and PFOA.

The most recent city test results are shown in the table below:

Well  PFOS  (ppt) Average PFOS Level PFOA  (ppt) Average PFOA Level 
Chino 2 ND ND 3.1 3.2 
Chino 3* ND ND 4.2 3.6 
Chino 4 ND ND ND ND 
Chino 5* ND ND 3.4 3.1 
Blended Chino Water ND ND ND ND 
Airport 2 ND ND ND ND 
Airport 3  ND ND 2.3 ND 
Airport 5* 8.6 9.5 11.6 12.9 

*Denotes wells not in operation when samples were taken

ND=Non-Detectable levels measured

ppt=parts per trillion

As a reference point, one part per trillion is equal to ¾ of a teaspoon in Watson Lake, so these test results show extremely low levels of PFAS in four city potable water supply wells.

As monthly test results are received in the future, city staff will immediately inform the public and quickly make operational changes to minimize the introduction of PFAS into city potable water supplies.

For more information about PFAS, please visit webpages by the US Environmental Protection Agency, Arizona Department of Environmental Protection, or the city’s PFAS Resource Page.