Free Arizona water report: PFAS & lead levels for every water system, worst-affected cities, and EPA violations. Check your ZIP.
Arizona is a desert state that has engineered its way to a water supply – and that engineering defines everything about water quality here. The state's 7.4 million residents depend on three primary sources: the Colorado River (delivered via the 336-mile Central Arizona Project canal), local rivers managed by the Salt River Project, and groundwater pumped from aquifers beneath the Sonoran Desert. The balance between these sources shifts by season, by region, and by drought conditions that have intensified over the past two decades.
The Arizona Department of Environmental Quality (ADEQ) oversees drinking water standards for approximately 1,600 public water systems. In the Phoenix metro – home to more than 60% of the state's population – water is a carefully managed blend of surface and groundwater. Tucson relies heavily on Central Arizona Project (CAP) water that is recharged into the local aquifer and then re-pumped, a process that affects mineral content and taste. Rural communities across the state, particularly on tribal lands, often depend on groundwater wells with limited monitoring.
Water hardness is a defining characteristic of Arizona's supply. Colorado River water averages over 300 mg/L total dissolved solids according to USGS assessments, making it some of the hardest municipal water in the country. This affects taste, plumbing longevity, and how treatment chemicals interact with the supply.
The EPA's UCMR5 monitoring has confirmed PFAS detections at multiple public water systems across Arizona. The contamination pattern is geographically concentrated: areas near military air bases in the Phoenix metro show the highest readings, while systems drawing from surface water sources without nearby PFAS point sources have generally tested lower.
Arizona does not currently have state-specific PFAS MCLs. The state follows the federal EPA standards established in 2024, with enforceable limits of 4 ppt for PFOA and PFOS. ADEQ has conducted supplemental PFAS monitoring beyond UCMR5 requirements, particularly around known contamination sources, but has not moved to adopt stricter state thresholds.
Groundwater contamination is the primary concern. In a state where aquifers are the backup supply during drought – and sometimes the primary supply – PFAS that reaches the water table poses a long-term problem. Unlike surface water, which can flush and dilute contaminants, groundwater in arid regions moves slowly and retains contamination for decades.
Luke Air Force Base in the western Phoenix metro is the most prominent PFAS contamination source in Arizona. The Air Force has confirmed PFAS in groundwater on and around the base from decades of AFFF use. Contamination plumes have been detected in monitoring wells serving nearby communities in Goodyear and Glendale. The Department of Defense has provided alternative water supplies to affected residents and is conducting remediation, but the timeline stretches years into the future.
Tucson faces its own military contamination legacy. Davis-Monthan Air Force Base, located within the city, has confirmed PFAS detections in surrounding groundwater. For a city that depends heavily on groundwater – Tucson was one of the last major US cities to fully transition to its CAP allocation – military PFAS adds a complication to an already stressed supply.
Other Arizona military sites under PFAS investigation include Williams Air Force Base (now Phoenix-Mesa Gateway Airport, a former active installation with documented contamination), the former Falcon Field military training site, and the Yuma Proving Ground. The Department of Defense PFAS Task Force has flagged these sites for assessment or ongoing remediation. See our military bases page for the complete list.
ADEQ has taken a monitoring-focused approach to PFAS, expanding testing around known contamination sites while relying on federal standards for enforcement. The agency published a PFAS Action Plan that outlines investigation priorities, stakeholder engagement, and coordination with the Department of Defense on military site cleanups.
Under UCMR5, Arizona's larger public water systems tested for 29 PFAS compounds between 2023 and 2025. Results showed a clear geographic pattern: systems in the West Valley near Luke AFB and in Tucson near Davis-Monthan had the most significant detections, while systems in northern Arizona and rural areas without PFAS point sources had fewer or no detections.
According to ADEQ's water quality reports, approximately 35% of Arizona's population relies on groundwater as their primary drinking water source. Private wells, which serve a significant number of rural and tribal community residents, are not subject to PFAS testing requirements. For these communities, contamination may exist without anyone knowing.
For background on what PFAS compounds are and how they affect health, see our PFAS guide.
Arizona's water quality varies by source, by region, and by proximity to contamination sites. The Phoenix metro, Tucson, and rural communities each face different profiles.
1. Check your ZIP code at the homepage to see monitoring data specific to your area. We pull from UCMR5, ADEQ reports, and utility Consumer Confidence Reports. 2. If you live in the West Valley near Luke AFB or in Tucson near Davis-Monthan, a reverse osmosis filter is the most effective household option for PFAS. Our water filter guide explains which systems are certified for PFAS removal versus which just claim to be. 3. For hardness and total dissolved solids – a quality-of-life issue across much of Arizona – a water softener or RO system can help. These are separate from PFAS filters, and our guide covers both. 4. Request a detailed water report for your address to see multi-year trends and compare your area to state averages.
In a state where water is the defining resource constraint, knowing exactly what is in your supply is not optional. Check your specific location to see current data for your area.