The Power of Information

National Drinking Water Database


753 systems serving 4,995,854 people

This drinking water quality report shows results of tests conducted by water utilities in Arizona, provided to the Environmental Working Group (EWG) by the Arizona Department of Environmental Quality. It is part of EWG's national database that includes 47,667 drinking water utilities and 20 million test results from 45 states and the District of Columbia. Water utilities nationwide detected more than 300 pollutants between 2004 and 2009. More than half of these chemicals are unregulated, legal in any amount. Despite this widespread contamination, the federal government invests few resources in protecting rivers, reservoirs, and groundwater from pollution in the first place. The information below summarizes drinking water quality for this state.

Water Utilities
Population Served
Detected Chemicals
Exceed health guidelines*
Exceed Legal Limits*
Unregulated chemicals detected
* Water utilities are noted as exceeding the legal limit if any test is above the maximum contaminant level (MCL). Most MCLs are based on annual averages so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.

37 Contaminants Exceeding Health Based Limits

Contaminants detected in Arizona drinking water above health guidelines, according to an Environmental Working Group analysis of data obtained from state water authorities

Number of Systems
At Any Level Above Health Limits At Any Level Above Health Limits
Arsenic (total)4,596,8724,596,872501501
Total haloacetic acids (HAAs)4,361,8924,281,536186175
Alpha particle activity (excl radon and uranium)3,845,8013,845,8016666
Di(2-ethylhexyl) phthalate3,325,6803,325,6804343
Total trihalomethanes (TTHMs)4,633,5703,102,899286105
Lead (total)2,704,5932,704,593380380
Dichloroacetic acid2,441,5512,441,5517070

Water Utilities in Arizona Reporting Chemicals Exceeding Health Guidelines

Water utilities in Arizona reporting chemicals exceeding health guidelines, according to an Environmental Working Group analysis of data obtained from state water authorities, include:

Chemicals tested
Chemicals found
Chemicals exceeding
health guidelines
Town of Gilbert100,0001192818
City of Meza Utilities Department350,000972917
City of Chandler180,0001013717
City of Peoria86,0001043115
Metropolitan Dwid43,4331172713
City of Tempe160,0001121913
City of Scottsdale180,000973113
City of Flagstaff41,200891913
City of Lake Havasu43,000901912
City of Glendale180,000932112
City of Avondale22,0001292712
Adot Airport Grand Canyon3,750881912
City of Yuma103,264862011
Sherman Pines Water Co90902211
Ponderosa Park Water Impr500911911
Tucson Water675,000902511
AZ American Water - Anthem Water System3,000822111
Goodyear, Munic Water Dep16,3081102011
City of Page9,750821611
Rio Lindo62481610

Sources of Arizona Drinking Water Contaminants

The contaminants identified in Arizona drinking water come from a wide variety of sources, including agriculture, industry, water treatment plants, and polluted storm runoff from urban areas.

68Total Contaminants Detected (2004 - 2009)
17Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Arsenic (total), Cyanide, Nitrate & nitrite, Nitrate, Nitrite, Selenium (total), Dalapon, Diquat, Simazine, Dinoseb, Atrazine, 2,4-D, 1,2-Dibromo-3-chloropropane (DBCP), Ethylene dibromide (EDB), Chlordane, p-Dichlorobenzene, Ethylbenzene

18Sprawl and Urban Pollutants
(road runoff, lawn pesticides, human waste)

Nitrate, Copper, Nitrate & nitrite, Lead (total), Arsenic (total), Tetrachloroethylene, Nitrite, Xylenes (total), Dalapon, Cadmium (total), Antimony (total), Mercury (total inorganic), Cyanide, p-Dichlorobenzene, 2,4-D, Chlordane, Benzo[a]pyrene, 2,3,7,8-TCDD (Dioxin)

43Industrial Pollutants

Arsenic (total), Chlorite, Barium (total), Cadmium (total), Chromium (total), Cyanide, Lead (total), Mercury (total inorganic), Nitrate & nitrite, Nitrate, Nitrite, Selenium (total), Antimony (total), Beryllium (total), Thallium (total), Asbestos, Di(2-ethylhexyl) phthalate, Hexachlorocyclopentadiene, 2,3,7,8-TCDD (Dioxin), Hexachlorobenzene (HCB), Pentachlorophenol, cis-1,2-Dichloroethylene, Ethylene dibromide (EDB), Xylenes (total), p-Dichlorobenzene, Vinyl chloride, 1,1-Dichloroethylene, 1,1-Dichloroethane, Trichloroethylene, Tetrachloroethylene, Toluene, Ethylbenzene, Styrene, Alpha particle activity (excl radon and uranium), Alpha particle activity (incl. radon & uranium), Combined Uranium (mg/L), Uranium-234, Uranium-235, Uranium-238, Combined Radium (-226 & -228), Radium-226, Radium-228, Combined Uranium (pCi/L)

18Water Treatment and Distribution Byproducts
(pipes and fixtures, treatment chemicals and byproducts)

Total trihalomethanes (TTHMs), Total haloacetic acids (HAAs), Chloroform, Bromodichloromethane, Dibromochloromethane, Dichloroacetic acid, Trichloroacetic acid, Bromoform, Dibromoacetic acid, Monochloroacetic acid, Monobromoacetic acid, Chlorite, Di(2-ethylhexyl) phthalate, Cadmium (total), Bromate, Vinyl chloride, Asbestos, Benzo[a]pyrene

22Naturally Occurring
(naturally present but increased for lands denuded by sprawl, agriculture, or industrial development)

Nitrate, Copper, Nitrate & nitrite, Barium (total), Lead (total), Arsenic (total), Radium-228, Radium-226, Alpha particle activity (excl radon and uranium), Combined Radium (-226 & -228), Combined Uranium (pCi/L), Chromium (total), Alpha particle activity (incl. radon & uranium), Combined Uranium (mg/L), Selenium (total), Nitrite, Radon, Mercury (total inorganic), Cyanide, Uranium-238, Uranium-234, Uranium-235

5Unregulated Contaminants
EPA has not established a maximum legal limit in tapwater for these contaminants

Lead (total), 1,1-Dichloroethane, Radon, Uranium-234 (pCi/L), Uranium-238 (pCi/L)

Testing Summary for Arizona

The federal government has set standards for some of the pollutants found in tap water supplies.

Contaminants reported as tested by water suppliers in Arizona156
 Contaminants tested due to federal law: 99
 Contaminants tested in addition to those required by federal law: 57

Violation Summary for Arizona

Data from the U.S. Environmental Protection Agency includes the following violations of federal standards in Arizona since 2004

Violation TypeNumber of Violations
Failure to monitor regularly6,280
Monitoring and Reporting Disinfection Byproduct Rule5,411
Failure to monitor, Routine Major (Coliform bacteria)2,963
Failure to report information to the public or state agency in the Consumer Confidence Report1,871
Follow-up and Routine Tap Sampling918
Failure to monitor, Routine Minor (Coliform bacteria)852
Failure to monitor, Repeat Major (Coliform bacteria)428
Maximum contaminant level, Monthly (Coliform bacteria)304
Over maximum contaminant level, Average271
Initial Tap Sampling for Lead and Copper262
Failure to monitor, Repeat Minor (Coliform bacteria)98
Over maximum contaminant level, Single Sample86
Filter Turbidity Reporting81
Failure to monitor: Check/Repeat/Confirmation sampling28
Maximum contaminant level, Acute (Coliform bacteria)9
Non-Acute maximum residual disinfectant level9
Treatment Technique (Surface Water Treatment Rule)2
Excess Turbidity at 1 NTU1
Inadequate reporting of information to the public1