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EWG's Tap Water Database — 2021 UPDATE

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Maricopa Mountain Domestic Water Improvement District 1

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 (January 2021 - March 2021), tap water provided by this water utility was in compliance with federal health-based drinking water standards.

Utility Details

  • Stanfield, Arizona
  • Serves: 450
  • Data available: 2014-2019
  • Source: Groundwater

Contaminants Detected

6

EXCEED
EWG HEALTH
GUIDELINES

10 Total Contaminants

  • 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.

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Contaminants Detected

Arsenic

Potential Effect: cancer375x EWG'S HEALTH GUIDELINE
THIS UTILITY1.50 ppb
EWG HEALTH GUIDELINE0.004 ppb
LEGAL LIMIT10 ppb
DETAILS
X

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 375 times above EWG's Health Guideline.

EWG Health Guideline

0.004 ppb or less

This Utility

1.5 ppb

Legal Limit

10 ppb

National Average

0.647 ppb

State Average

4.17 ppb
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

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.

Pollution Sources

Agriculture

Industry

Naturally Occurring

Filtering Options

Reverse Osmosis

Ion Exchange

Haloacetic acids (HAA5)†

Potential Effect: cancer28x EWG'S HEALTH GUIDELINE
THIS UTILITY2.80 ppb
EWG HEALTH GUIDELINE0.1 ppb
LEGAL LIMIT60 ppb
DETAILS
X

Haloacetic acids (HAA5)

more about
this contaminant

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 28 times above EWG's Health Guideline.

EWG Health Guideline

0.1 ppb or less

This Utility

2.8 ppb

Legal Limit

60 ppb

National Average

17.1 ppb

State Average

8.13 ppb
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

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.

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Nitrate

Potential Effect: cancer70x EWG'S HEALTH GUIDELINE
THIS UTILITY9.74 ppm
EWG HEALTH GUIDELINE0.14 ppm
LEGAL LIMIT10 ppm
DETAILS
X

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 70 times above EWG's Health Guideline.

EWG Health Guideline

0.14 ppm or less

This Utility

9.74 ppm

Legal Limit

10 ppm

National Average

0.935 ppm

State Average

2.48 ppm
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppm = parts per million

Health Risks

The EWG Health Guideline of 0.14 ppm for nitrate was defined by EWG . This health guideline protects against cancer and harm to fetal growth and development.

Pollution Sources

Agriculture

Runoff & Sprawl

Naturally Occurring

Filtering Options

Reverse Osmosis

Ion Exchange

Nitrate and nitrite

over legal limit
THIS UTILITY10.3 ppm
EWG HEALTH GUIDELINE0.14 ppm
LEGAL LIMIT10 ppm
DETAILS
X

Nitrate and nitrite

more about
this contaminant

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 74 times above EWG's Health Guideline.

EWG Health Guideline

0.14 ppm or less

This Utility

10.3 ppm

Legal Limit

10 ppm

National Average

0.888 ppm

State Average

2.69 ppm
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppm = parts per million

Health Risks

The 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.

Pollution Sources

Agriculture

Runoff & Sprawl

Naturally Occurring

Filtering Options

Reverse Osmosis

Ion Exchange

Total trihalomethanes (TTHMs)†

Potential Effect: cancer29x EWG'S HEALTH GUIDELINE
THIS UTILITY4.40 ppb
EWG HEALTH GUIDELINE0.15 ppb
LEGAL LIMIT80 ppb
DETAILS
X

Total trihalomethanes (TTHMs)

more about
this contaminant

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 29 times above EWG's Health Guideline.

EWG Health Guideline

0.15 ppb or less

This Utility

4.4 ppb

Legal Limit

80 ppb

National Average

29.7 ppb

State Average

30.5 ppb
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2017-2019.
ppb = parts per billion

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.

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Uranium

Potential Effect: cancer27x EWG'S HEALTH GUIDELINE
THIS UTILITY11.59 pCi/L
EWG HEALTH GUIDELINE0.43 pCi/L
LEGAL LIMIT20 pCi/L
DETAILS
X

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 27 times above EWG's Health Guideline.

EWG Health Guideline

0.43 pCi/L or less

This Utility

11.59 pCi/L

Legal Limit

20 pCi/L

National Average

1.04 pCi/L

State Average

2 pCi/L
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2014-2019.
pCi/L = picocuries per liter

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.

Pollution Sources

Industry

Naturally Occurring

Filtering Options

Reverse Osmosis

Ion Exchange

Includes chemicals detected in 2017-2019 for which annual utility averages exceeded the federal Maximum Contaminant Level (MCL); chemicals detected in 2017-2019 for which annual utility averages exceeded an EWG-selected health guideline established by a federal or state public health authority; radiological contaminants detected between 2014 and 2019.

† 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


Maricopa Mountain Domestic Water Improvement District 1 compliance with legally mandated federal standards:

  • From April 2019 to March 2021, Maricopa Mountain Domestic Water Improvement District 1 complied with health-based drinking water standards.
  • 9 QUARTERS
    in violation of any federal drinking water standard from April 2019 to March 2021
  • Over the last 3 years this water utility has spent
    2 QUARTERS
    in significant violation of federal drinking water standards

Information in this section on Maricopa Mountain Domestic Water Improvement District 1 comes from the U.S. EPA Enforcement and Compliance History Online database (ECHO).

LEARN MORE ABOUT THIS UTILITY

Water Filters That Can Reduce Contaminant Levels

ContaminantActivated Carbonactivated carbonReverse Osmosisreverse osmosisIon Exchangeion exchange
CONTAMINANTS ABOVE
HEALTH GUIDELINES
Arsenic
Haloacetic acids (HAA5)
Nitrate
Nitrate & nitrite
Total trihalomethanes (TTHMs)
Uranium, combined (pCi/L)
OTHER CONTAMINANTS
DETECTED
Barium
Chromium (total)
Fluoride
Selenium

Take Action

Contact Your Local Official

One of the best ways to push for cleaner water is to hold accountable the elected officials who have a say in water quality – from city hall and the state legislature to Congress all the way to the Oval Office – by asking questions and demanding answers.

LEARN MORE

Filter Out Contaminants

Check out our recommendations for filters to protect your water against the detected contaminants.

EWG’S WATER FILTER GUIDE