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Arizona Water Quality
333
Utilities in database
7.2M
Residents served
18%
On private wells
4
Key contaminants tracked
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.
Utilities in Arizona
Detailed utility pages for Arizona are being prepared and will go live soon. Browse available states →
Key Contaminant Concerns in Arizona
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.
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.
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.
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.
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Top Contaminants in AZ
Data source: Utility data from EPA SDWIS. 333 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2025-01-10