Overview
EWG's drinking water quality report shows results of tests conducted by the water utility and provided to the Environmental Working Group by the Arizona Department of Environmental Quality, as well as information from the U.S. EPA Enforcement and Compliance History database (ECHO). For the latest quarter assessed by the U.S. EPA (April 2024 - June 2024), tap water provided by this water utility was in serious violation federal health-based drinking water standards.
Legal does not necessarily equal safe.
Getting a passing grade from the federal government does not mean the water meets the latest health guidelines.
Legal limits for contaminants in tap water have not been updated in almost 20 years.
The best way to ensure clean tap water is to keep pollution out of source water in the first place.
Contaminants Detected
Arsenic
Potential Effect: cancer
This Utility: 4.15 ppb
Legal Limit: 10 ppb
1,036x
EWG's Health Guideline: 0.004 ppb
Arsenic
Arsenic is a potent carcinogen and common contaminant in drinking water. Arsenic causes thousands of cases of cancer each year in the U.S. Click here to read more about arsenic.
Arsenic was found at 1,036 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
Legal Limit
National Average
State Average
Health Risks
The EWG Health Guideline of 0.004 ppb for arsenic was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2021-2023.
ppb = parts per billionPollution Sources
Agriculture
Industry
Naturally Occurring
Filtering Options
Reverse Osmosis
Ion Exchange
Bromodichloromethane
Potential Effect: cancer
This Utility: 30.8 ppb
No Legal Limit
514x
EWG's Health Guideline: 0.06 ppb
Bromodichloromethane
Bromodichloromethane, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Bromodichloromethane and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.
Bromodichloromethane was found at 514 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 0.06 ppb for bromodichloromethane was based on the California Office of Environmental Health Hazard Assessment's public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer and harm to fetal growth and development.
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2021-2023.
ppb = parts per billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Bromoform
Potential Effect: cancer
This Utility: 7.96 ppb
No Legal Limit
16x
EWG's Health Guideline: 0.5 ppb
Bromoform
Bromoform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Bromoform and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.
Bromoform was found at 16 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 0.5 ppb for bromoform is based on the California Office of Environmental Health Hazard Assessment's public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer, harm to reproduction and child development, and change to fetal growth and development .
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2021-2023.
ppb = parts per billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Chloroform
Potential Effect: cancer
This Utility: 38.2 ppb
No Legal Limit
96x
EWG's Health Guideline: 0.4 ppb
Chloroform
Chloroform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Chloroform and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy.
Chloroform was found at 96 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 0.4 ppb for chloroform was based on the California Office of Environmental Health Hazard Assessment's public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer and harm to fetal growth and development.
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2021-2023.
ppb = parts per billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Dibromochloromethane
Potential Effect: cancer
This Utility: 31.7 ppb
No Legal Limit
317x
EWG's Health Guideline: 0.1 ppb
Dibromochloromethane
Dibromochloromethane, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Dibromochloromethane and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.
Dibromochloromethane was found at 317 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 0.1 ppb for dibromochloromethane was based on the California Office of Environmental Health Hazard Assessment's public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer and harm to fetal growth and development.
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2021-2023.
ppb = parts per billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Haloacetic acids (HAA5)
Potential Effect: cancer
This Utility: 22.9 ppb
Legal Limit: 60 ppb
229x
EWG's Health Guideline: 0.1 ppb
Haloacetic acids (HAA5)
Haloacetic acids are formed when disinfectants such as chlorine are added to tap water. The group of five haloacetic acids regulated by federal standards includes monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid.
Haloacetic acids (HAA5) was found at 229 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
Legal Limit
National Average
State Average
Health Risks
The EWG Health Guideline of 0.1 ppb for the group of five haloacetic acids, or HAA5, was defined in a peer-reviewed scientific study by EWG and represents a one-in-a-million lifetime cancer risk level. This health guideline protects against cancer.
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2021-2023.
ppb = parts per billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Nitrate
Potential Effect: cancer
This Utility: 1.14 ppm
Legal Limit: 10 ppm
8.1x
EWG's Health Guideline: 0.14 ppm
Nitrate
Nitrate, a fertilizer chemical, frequently contaminates drinking water due to agricultural and urban runoff, and discharges from municipal wastewater treatment plants and septic tanks. Excessive nitrate in water can cause oxygen deprivation in infants and increase the risk of cancer. Click here to read more about nitrate.
Nitrate was found at 8.1 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
Legal Limit
National Average
State Average
Health Risks
The EWG health guideline of 0.14 parts per million, or ppm, for nitrate and nitrite is based on the equivalent health guideline for nitrate, as defined in a peer-reviewed scientific study by EWG. This guideline represents a one-in-one-million annual cancer risk level.
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2021-2023.
ppm = parts per millionPollution Sources
Agriculture
Runoff & Sprawl
Naturally Occurring
Filtering Options
Reverse Osmosis
Ion Exchange
Nitrate and nitrite
Potential Effect: cancer
This Utility: 2.80 ppm
Legal Limit: 10 ppm
20x
EWG's Health Guideline: 0.14 ppm
Nitrate and nitrite
Nitrate and nitrite enter water from fertilizer runoff, septic tanks and urban runoff. These contaminants can cause oxygen deprivation for infants and increase the risk of cancer. Nitrite is significantly more toxic than nitrate. Click here to read more about nitrate.
Nitrate and nitrite was found at 20 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
Legal Limit
National Average
State Average
Health Risks
The EWG health guideline of 0.14 parts per million, or ppm, for nitrate and nitrite is based on the equivalent health guideline for nitrate, as defined in a peer-reviewed scientific study by EWG. This guideline represents a one-in-one-million annual cancer risk level.
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2021-2023.
ppm = parts per millionPollution Sources
Agriculture
Runoff & Sprawl
Naturally Occurring
Filtering Options
Reverse Osmosis
Ion Exchange
Total trihalomethanes (TTHMs)
Over Legal Limit
This Utility: 101.0 ppb
Legal Limit: 80 ppb
EWG's Health Guideline: 0.15 ppb
Total trihalomethanes (TTHMs)
Trihalomethanes are cancer-causing contaminants that form during water treatment with chlorine and other disinfectants. The total trihalomethanes group includes four chemicals: chloroform, bromodichloromethane, dibromochloromethane and bromoform.
Total trihalomethanes (TTHMs) was found at 674 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
Legal Limit
National Average
State Average
Health Risks
The health guideline of 0.15 parts per billion, or ppb, for the group of four trihalomethanes, or THM4/TTHM, was defined in a peer-reviewed scientific study by EWG and represents a one-in-one-million lifetime cancer risk level.
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2021-2023.
ppb = parts per billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Uranium
Potential Effect: cancer
This Utility: 18.96 pCi/L
Legal Limit: 20 pCi/L
44x
EWG's Health Guideline: 0.43 pCi/L
Uranium
Uranium is a known human carcinogen. The federal legal limit for uranium is set at 30 micrograms per liter (corresponding to parts per billion), but utilities can also report uranium in picocuries per liter (pCi/L), which is a measure of radioactivity in water. EWG translated all uranium results to pCi/L using a conversion factor developed by the EPA. With this conversion approach, the limit of 30 ppb corresponds to 20 pCi/L. Drinking water with this much uranium would cause more than 4.6 cancer cases in a population of 100,000. California set a public health goal for uranium of 0.43 pCi/L.
Uranium was found at 44 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
Legal Limit
National Average
State Average
Health Risks
The EWG Health Guideline of 0.43 pCi/L for uranium was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. Three most common uranium isotopes are U-234, U-235 and U-238. All isotopes of uranium are radioactive, and the total radioactivity depends on the ratio of isotopes. This health guideline protects against cancer.
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2018-2023.
pCi/L = picocuries per literPollution Sources
Industry
Naturally Occurring
Filtering Options
Reverse Osmosis
Ion Exchange
Includes chemicals detected in 2021-2023 for which annual utility averages exceeded the federal Maximum Contaminant Level (MCL); chemicals detected in 2021-2023 for which annual utility averages exceeded an EWG-selected health guideline established by a federal or state public health authority; radiological contaminants detected between 2018 and 2023.
† HAA5 is a contaminant group that includes monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid. HAA9 is a contaminant group that includes the chemicals in HAA5 and bromochloroacetic acid, bromodichloroacetic acid, chlorodibromoacetic acid and tribromoacetic acid. TTHM is a contaminant group that includes bromodichloromethane, bromoform, chloroform and dibromochloromethane.
Other Contaminants Tested
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| CONTAMINANTS ABOVE HEALTH GUIDELINES | activated carbon | reverse osmosis | ion exchange |
| Arsenic | |||
| Bromodichloromethane | |||
| Bromoform | |||
| Chloroform | |||
| Dibromochloromethane | |||
| Haloacetic acids (HAA5) | |||
| Nitrate | |||
| Nitrate & nitrite | |||
| Total trihalomethanes (TTHMs) | |||
| Uranium, combined (pCi/L) |
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