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AZ

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Arizona Water Quality

333

Utilities in database

7.2M

Residents served

2

With open violations

144

PFAS monitored

Quick Answer

Arizona public drinking water is served by 333 EPA-tracked water systems, providing service to approximately 7.2 million residents through public utilities. 2 of those systems currently have open health-based violations on record in the EPA federal database. 144 systems have official PFAS monitoring records from the EPA UCMR 5 program (2023–2025). About 18% of AZ residents use private wells, which fall outside federal utility compliance monitoring.

2 Arizona water systems have open health-based violations recorded in EPA SDWIS. An open violation means a contaminant exceeded a federal limit and the violation has not been formally resolved in the federal database. Check individual utility pages for current status.

Open Health-Based Violations in Arizona

Records sourced from EPA SDWIS. A record may be under review or resolved at the utility level but not yet updated in federal records. Water Utility Report does not determine whether water is safe to drink.

Drinking Water in Arizona

Arizona's water supply depends heavily on the Colorado River (delivered via the Central Arizona Project) and local groundwater. Naturally occurring arsenic is a significant issue in rural areas — Arizona has some of the highest naturally occurring arsenic levels in the U.S. Hard water and PFAS contamination near military installations are also documented. ADEQ holds primary enforcement authority.

Highest Risk Utilities

Arizona systems with open health-based violations in EPA records.

Safest Large Utilities

Arizona systems with no open health violations serving 10,000+ residents.

Utilities in Arizona

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Key Contaminant Concerns in Arizona

These contaminants appear most frequently in Arizona utility records or pose elevated risk in this region based on EPA data.

high

PFAS

Per- and polyfluoroalkyl substances (PFAS) are a class of over 12,000 synthetic chemicals characterized by strong carbon-fluorine bonds that resist degradation. The two most studied — PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid) — have been phased out of U.S. manufacturing but persist widely in the environment.

EPA limit: 4 ppt

moderate

DBPs

When utilities add chlorine to water to kill pathogens, it reacts with dissolved organic matter — leaves, algae, soil — to produce disinfection byproducts (DBPs). Over 600 DBPs have been identified. The EPA regulates two groups: total trihalomethanes (TTHMs, including chloroform) and haloacetic acids (HAA5). DBP levels tend to be highest in surface water systems and in warm months when organic matter is elevated.

EPA limit: 80 µg/L (TTHMs) / 60 µg/L (HAA5)

moderate

Arsenic

Arsenic (As) occurs naturally in rock and soil, dissolving into groundwater through natural weathering processes. Inorganic arsenic — the form found in drinking water — is a known human carcinogen. The western United States has particularly arsenic-rich geological formations, but elevated levels have been found in 48 states. Arsenic is tasteless and odorless.

EPA limit: 10 ppb

low

Hard Water

Water hardness is a measure of dissolved calcium (Ca²⁺) and magnesium (Mg²⁺) ions, expressed in milligrams per liter (mg/L) as calcium carbonate (CaCO₃) or grains per gallon (gpg). Water below 60 mg/L is considered soft; 61–120 mg/L is moderately hard; 121–180 mg/L is hard; above 180 mg/L is very hard. The Colorado River, which supplies water to much of the Southwest, is among the hardest source waters in the U.S.

EPA limit: No federal limit

City Water Reports in Arizona

Tap water quality pages for Arizona cities — violations, PFAS records, utility profiles, and official source links.

Arizona PFAS Watchlist — all utilities with official records

Independent Water Testing

Find a certified lab in Arizona

Utility compliance records show what water systems report to the EPA. An independent test from a certified laboratory confirms what's actually in your tap water. Arizona labs can test for PFAS, lead, nitrates, bacteria, and dozens of other contaminants.

Explore Water Quality in Arizona

Common Questions About Arizona Drinking Water

Arizona Water FAQs

Data sources: Utility compliance and violation data from EPA SDWIS (Safe Drinking Water Information System). PFAS monitoring records from EPA UCMR 5 (Unregulated Contaminant Monitoring Rule 5, 2023–2025). Contaminant data from EPA and ATSDR public references. This page summarizes public records — it is not a compliance determination. Methodology →

Last updated: 2025-01-10