Water Quality

We monitor for potential contaminants and key constituents to ensure that your drinking water is of high quality.

As a public water system (PWS), the City of Flagstaff is required under the Safe Drinking Water Act (SDWA) to monitor for potential contaminants — chemical and biological — to ensure that we are providing clean drinking water to citizens. They include:
  • Microbial contaminants, such as viruses and bacteria, which may originate from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife
  • Inorganic contaminants, such as salts and metals, which can occur naturally or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining, or farming
  • Pesticides and herbicides, which may come from a variety of sources, such as agriculture, urban stormwater runoff, and residential uses
  • Organic chemical contaminants, including synthetic and volatile organic chemicals (SOCs and VOCs), which are byproducts of industrial processes and petroleum production and can also come from gas stations, urban stormwater runoff, and septic systems
  • Radioactive contaminants, which can be naturally occurring or be the result of oil and gas production and mining activities
The U.S. Environmental Protection Agency (EPA) specifies levels of each potential contaminant that are safe for human consumption.

Annual Water Quality Monitoring Results

In 2015, we discovered that we missed some required sampling in 2014 and immediately took steps to correct this error. Even though these omissions did not result in emergencies or threats to human health, as our customers, you have a right to know what happened. During 2014, we failed to monitor for VOCs at two wells. In addition, between 2012 and 2014, we only collected one of the two required SOC samples for eight wells. Therefore, although we cannot be sure of the quality of our drinking water during that time, based on historical results for these sites, violations are highly unlikely. Furthermore, in 2015, all of these samples were collected and compliance was restored and we have taken corrective actions to ensure that this never happens again. There was only one exceedance in 2015. Haloacetic Acids (HAA5), a byproduct of the drinking water disinfection process, was detected at a concentration that was just above the regulatory limit. Again, we took immediate action to correct this issue.

Source Water Assessment Program


The Arizona Department of Environmental Quality (ADEQ) administers the Source Water Assessment Program (SWAP) as part of the nationwide Safe Drinking Water Act.  This program evaluates all sources of water that provide drinking water to public water systems, and rates the level of risk (threat) to the water integrity, termed source water protection.  Flagstaff has an overall low risk rating in the SWAP evaluations.  To read the entire report, click here.

Annual Reports

We publish annual reports on drinking water quality summarizing the results of this monitoring. You can download them here or obtain printed copies at the downtown public library Information Desk or the Water Services Division office on the second floor of City Hall (211 W. Aspen). For questions about water quality, call the Lake Mary Water Treatment Plant at (928) 774-0262.