PFAS in Phoenix tap water 2026: ADEQ and EPA detection data

The City of Phoenix Water Services delivers drinking water to more than 1.6 million residents from surface sources that include the Salt River and Verde River, treated at five water treatment plants across the metro, according to the City of Phoenix Annual Water Quality Report at phoenix.gov/waterservices. That surface-water origin distinguishes Phoenix from Maricopa County communities that rely on groundwater wells, which tend to accumulate higher PFAS concentrations from soil and aquifer contamination pathways. Phoenix monitored for 29 PFAS compounds under the EPA fifth Unregulated Contaminant Monitoring Rule from January 2023 through December 2025. The Arizona Department of Environmental Quality maintains statewide PFAS data at azdeq.gov. The EPA finalized maximum contaminant levels for PFOA and PFOS at 4 parts per trillion in April 2024, with a compliance deadline of 2029. For households that want point-of-use protection today, a reverse osmosis system certified to NSF/ANSI Standard 58 is the treatment method EPA guidance identifies as effective for reducing PFAS. Schedule a free water test at phoenixaquawellness.com to measure what is actually in your tap water.

What PFAS are and why Phoenix residents are asking about them

PFAS, short for per- and polyfluoroalkyl substances, are a class of thousands of synthetic chemicals manufactured since the 1940s. They appear in non-stick cookware coatings, food-contact packaging, stain-resistant textiles, and aqueous film-forming foam used by military and airport fire crews to suppress fuel fires. The carbon-fluorine bond that makes these chemicals industrially useful resists breakdown in the environment and in human biology, earning the category its common label of forever chemicals.

Health research has documented associations between PFAS exposure and immune system effects, thyroid disruption, elevated cholesterol, and certain cancers at high concentrations, according to the EPA April 2024 rulemaking at epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas. PFOA and PFOS, the two most-studied compounds, were phased out of US manufacturing by the mid-2000s under voluntary agreements, but they persist widely in the environment from decades of prior industrial and military use. That persistence, combined with the new 4 ppt MCL and the 2029 compliance deadline, is why Phoenix area homeowners are checking UCMR 5 data and asking about their tap water now rather than waiting for utilities to notify them.

Phoenix tap water sources and the PFAS risk picture

Phoenix Water Services draws between 97 and 99 percent of its water supply from surface sources, primarily the Salt River and Verde River, which feed reservoirs managed by the Salt River Project. Colorado River water delivered through the Central Arizona Project provides supplemental supply. All surface water is treated at five plants before entering the distribution network, according to the City of Phoenix at phoenix.gov/waterservices. Surface water from rivers and reservoirs typically carries lower PFAS concentrations than groundwater drawn from aquifers beneath former industrial or military sites, because dilution and distance from point-source contamination affect surface water differently than confined aquifer systems.

This context matters when comparing Phoenix UCMR 5 results to nearby groundwater-dependent systems in Maricopa County. Several communities that rely more heavily on groundwater wells recorded PFAS detections above the new 4 ppt MCL during the monitoring period. Tempe recorded PFOS at 55.80 ng/L and PFOA at 38.70 ng/L in January 2025 samples, more than thirteen times the federal limit, per data compiled at waterutilityreport.com. Gilbert recorded PFOS at 9.80 ng/L and PFOA at 6.50 ng/L. Peoria had PFOA detections at 5.60 ng/L. The distinctions in source water between these utilities and Phoenix reflect the different contamination pathways that affect surface water versus aquifer groundwater.

What EPA UCMR 5 found across Arizona drinking water systems

The EPA fifth Unregulated Contaminant Monitoring Rule ran from January 2023 through December 2025 and required public water systems serving more than 3,300 people to test for 29 PFAS compounds. Nationally, more than 3,500 community water systems had detectable PFAS, representing approximately 95 percent of the systems monitored under the rule, according to Environmental Working Group analysis at ewg.org/interactive-maps/pfas_contamination.

In Arizona, 57 drinking-water utilities reported at least one PFAS detection at or above the EPA minimum reporting level during the monitoring period. Of those, 27 utilities exceeded the final federal MCL for PFOA or PFOS, collectively serving roughly 1.74 million residents, per mapscaping.com analysis of the UCMR 5 dataset. The most commonly detected PFAS compounds across Arizona were PFBS (40 utilities), PFPeA (34 utilities), and PFHxA (32 utilities). Homeowners can review the full Arizona dataset using the EPA UCMR 5 Data Finder at epa.gov/dwucmr/fifth-unregulated-contaminant-monitoring-rule-data-finder, searching by state or by water system name.

The City of Phoenix results in UCMR 5 are accessible through the EPA Data Finder by filtering for Phoenix as the water system operator. Phoenix draws from the Salt and Verde rivers rather than from aquifers near known PFAS point sources, which is why its profile differs from utilities in the 27-system group that exceeded the MCL. Residents who want Phoenix-specific detection results rather than statewide summaries should use the system-level filter in the EPA Data Finder or download the City of Phoenix CCR directly at phoenix.gov/waterservices.

ADEQ PFAS monitoring: what Arizona regulators track

The Arizona Department of Environmental Quality monitors PFAS statewide and makes data available at azdeq.gov. ADEQ tracks both drinking water utility detections under the EPA monitoring rules and site-specific investigations at locations where aqueous film-forming foam was historically used. In Arizona, that category includes Luke Air Force Base in the northwest Valley, Davis-Monthan Air Force Base in Tucson, and Phoenix Sky Harbor International Airport, where historical fire training and emergency response operations involved PFAS-containing foam. ADEQ coordinates with the EPA on remediation at confirmed contamination sites and publishes monitoring results by county.

ADEQ data is most relevant to Phoenix area homeowners who are on private wells near known contamination sites rather than on the City of Phoenix municipal water system. Municipal customers are covered by UCMR 5 monitoring and the annual CCR, both of which document the utility-level results. Private well owners in proximity to Luke Air Force Base, Phoenix Sky Harbor, or former industrial sites should review ADEQ monitoring data at azdeq.gov and may be eligible for ADEQ private-well testing programs in affected zones.

The April 2024 EPA PFAS rule and the 2029 deadline for utilities

The EPA finalized the first enforceable national limits for PFAS in drinking water in April 2024. The rule sets Maximum Contaminant Levels for six PFAS: PFOA at 4 parts per trillion, PFOS at 4 ppt, HFPO-DA (GenX chemicals) at 10 ppt, PFNA at 10 ppt, PFHxS at 10 ppt, and a Hazard Index that applies when multiple PFAS compounds are present together. The full rule is documented at epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas.

Water utilities have until April 2029 to achieve compliance with the new MCLs. That five-year window reflects the capital investment required for utilities that need to install granular activated carbon systems, ion exchange treatment, or other PFAS-specific infrastructure at their treatment plants. During the compliance period, tap water at some utilities may legally contain PFAS above the new limits, because the prior standards remain in force until 2029. This is the gap that household point-of-use filtration addresses: an NSF-certified reverse osmosis system at the kitchen tap does not wait for utility upgrades.

How PFAS compares to other Phoenix water concerns

Phoenix area homeowners have historically focused on two water quality problems: hardness and chloramine. Phoenix water runs 12 to 22 grains per gallon, among the highest in the United States, requiring an ion-exchange water softener to protect appliances and plumbing. Chloramine, the disinfectant used across the valley's distribution network, requires catalytic carbon filtration to remove at the tap. Arsenic, regulated at 10 micrograms per liter by the EPA, appears in some Arizona groundwater systems. Trihalomethanes are a disinfection byproduct monitored in all surface-water systems.

PFAS differs from all of these in one key respect: no conventional residential treatment technology for hardness, chloramine, arsenic, or trihalomethanes will reliably reduce PFAS. A water softener exchanges calcium and magnesium for sodium and leaves PFAS entirely unaffected. Standard activated carbon has insufficient contact time in residential cartridges for reliable PFAS reduction. Chlorination does not degrade PFAS. The carbon-fluorine bond's stability means PFAS passes through most residential treatment stages intact, making RO the necessary addition to any complete Phoenix treatment stack.

What treatment removes PFAS from Phoenix tap water

Three treatment technologies are documented to reduce PFAS in water: reverse osmosis, granular activated carbon at high contact time, and ion exchange resin. For residential use, reverse osmosis is the most practical option. The EPA guidance on water filters certified to reduce PFAS, published at epa.gov/water-research/identifying-drinking-water-filters-certified-reduce-pfas, states that reverse osmosis systems can greatly reduce PFAS levels. An NSF/ANSI Standard 58-certified RO unit installed under the kitchen sink, with the supply line extended to the refrigerator and ice maker, provides PFAS reduction at every glass and cube without waiting for utility-level compliance in 2029.

• NSF/ANSI 58 certified reverse osmosis: greatly reduces PFOA, PFOS, and other PFAS through the semipermeable membrane stage; also reduces arsenic, nitrates, fluoride, lead, and TDS from Phoenix tap water's 550 to 700 ppm baseline
• Granular activated carbon at high contact time: effective at municipal treatment scale, insufficient in most residential under-sink cartridges where contact time is too short for reliable PFAS reduction
• Ion exchange resin: effective for PFAS, primarily deployed in municipal or commercial treatment systems rather than residential point-of-use units
• Water softeners: essential for Phoenix hardness, no effect on PFAS, must be paired with RO at the kitchen tap for complete drinking water treatment
• Standard pitcher filters: not certified for PFAS reduction unless specifically tested and labeled; verify NSF certification status independently before purchase
• Whole-home catalytic carbon filtration: removes chloramine and trihalomethanes site-wide, does not reliably reduce PFAS at residential contact times

A complete Phoenix water treatment stack addresses the full tap water profile: a catalytic carbon filter on the main line handles chloramine before water reaches any fixture, a water softener downstream handles hardness before it damages appliances, and an NSF 58-certified RO unit under the kitchen sink handles PFAS, arsenic, TDS, and fluoride at the drinking and cooking tap. Contact Aqua Wellness at (928) 451-1591 to schedule a free water test at your Phoenix address. An in-home test measures actual levels at your tap rather than relying on system-wide averages from the annual CCR.