Tucson water has some of the highest arsenic levels in Arizona at 280x above EWG health guidelines, PFOS (a PFAS compound) at 14x above guidelines linked to military base contamination, and uranium at 5.4x above guidelines. Tucson's water challenges are distinct from the Phoenix metro — the contaminant profile is shaped by different geology, different water sources, and proximity to Davis-Monthan Air Force Base.
Tucson Water serves 545,000+ residents primarily from a groundwater-heavy supply. Unlike Phoenix, which relies heavily on surface water from the Salt and Colorado rivers, Tucson historically depended almost entirely on groundwater wells. The city began integrating Colorado River water via the Central Arizona Project in the 2000s, but groundwater remains a major source — and groundwater is where the arsenic, uranium, and PFAS live.
Tucson's Contaminant Profile
Arsenic — 280x Above Health Guidelines
Tucson detected arsenic at 2.80 ppb, the highest in any Arizona metro city we track. The EWG guideline is 0.01 ppb. Arizona's Sonoran Desert geology is naturally rich in arsenic, and Tucson's reliance on deep groundwater wells concentrates this exposure. Arsenic is a known human carcinogen with no safe level of exposure according to current science.
PFOS (Forever Chemicals) — 14x Above Health Guidelines
PFOS was detected at 56 ppt versus the EWG guideline of 4 ppt. The contamination is directly linked to AFFF (aqueous film-forming foam) used at Davis-Monthan Air Force Base for decades. The PFAS plume has migrated into the groundwater that feeds several Tucson Water wells in the south and east parts of the city.
Tucson Water has taken the most contaminated wells offline and is installing treatment. But if you live in the south/southeast part of the city near the base, your exposure risk is higher than citywide averages suggest.
Uranium — 5.4x Above Health Guidelines
At 9.2 ppb versus a guideline of 1.7 ppb, Tucson has the highest uranium levels of any Arizona city we track. This is naturally occurring — Arizona's geology contains uranium deposits, and groundwater dissolves it over time. Uranium is a kidney toxin and carcinogen.
Haloacetic Acids (HAA9) — 583x Above Health Guidelines
At 35.0 ppb versus the guideline of 0.06 ppb. Lower than the Phoenix metro average but still hundreds of times above health-based levels.
Chromium-6 — 17x Above Health Guidelines
Detected at 0.52 ppb against a guideline of 0.03 ppb.
Tucson's Hard Water
Tucson water averages 12.3 GPG — classified as "very hard." While not as extreme as Scottsdale (20.1) or Mesa (17.1), it's still well above the national average and causes the same scale, soap, and appliance issues.
What Makes Tucson Different
Tucson's water story is unique in Arizona for a few reasons:
- PFAS is a bigger issue here than anywhere else in the state due to military contamination
- Arsenic and uranium are higher due to heavier reliance on deep groundwater
- Water source is transitioning — the integration of CAP water changes the profile over time
- South Tucson residents face higher risk due to proximity to the PFAS plume
What Tucson Residents Should Do
- Under-sink RO system: The single most important investment for Tucson homeowners. RO removes 90-99% of PFAS, 95-99% of arsenic, and 95-99% of uranium. This is not optional if you're drinking Tucson tap water unfiltered.
- Water softener: Recommended at 12.3 GPG to protect plumbing and appliances.
- If you're near Davis-Monthan: Consider having your water tested specifically for PFAS through a certified lab. Standard home tests don't typically include PFAS.
For the drinking water filter alone: start with a free test kit or book a free in-home water test.
Want answers specific to your home?
A 15-minute in-home water test tells you exactly what's coming out of your taps — hardness, TDS, chlorine, and more.
Book Your Free Water TestFrequently Asked Questions
Does Tucson water have PFAS?+
Yes. PFOS was detected at 56 ppt in Tucson water, primarily linked to contamination from Davis-Monthan Air Force Base. This is 14x above the EWG health guideline and above the new EPA MCL of 4 ppt. The most affected areas are in south and southeast Tucson near the base. Tucson Water has shut down the worst wells and is installing treatment.
Is Tucson water safe to drink in 2026?+
Tucson water meets federal legal limits but contains arsenic at 280x, PFOS at 14x, and uranium at 5.4x above health-based guidelines. A reverse osmosis filter is strongly recommended for drinking water, especially if you live near the PFAS contamination zone in south Tucson.
Why does Tucson have higher arsenic than Phoenix?+
Tucson relies more heavily on deep groundwater wells that pass through arsenic-rich geology. Phoenix uses more surface water (rivers), which naturally has lower arsenic. As Tucson integrates more Colorado River water through the CAP, arsenic levels may decrease over time in some areas.
What filter removes PFAS from water?+
Reverse osmosis (RO) is the most effective home solution, removing 90-99% of PFAS compounds. High-quality activated carbon filters can remove 60-90% of longer-chain PFAS like PFOS and PFOA. Basic pitcher filters provide minimal PFAS reduction.
Keep Reading
About The Very Good Water Company
We help Arizona homeowners understand what's really in their water — and what to do about it. No scare tactics, no upsells. Just independent data, honest recommendations, and systems that actually work for desert water. Based in Mesa, serving the entire Valley.