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EWG's Tap Water Database — 2021 UPDATE

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Preston, City of

EWG's drinking water quality report shows results of tests conducted by the water utility and provided to the Environmental Working Group by the Idaho 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

  • Preston, Idaho
  • Serves: 5,230
  • Data available: 2014-2019
  • Source: Groundwater

Contaminants Detected

3

EXCEED
EWG HEALTH
GUIDELINES

6 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.

Legal ≠ Safe

EWG Health Guidelines fill the gap in outdated government standards.

The federal government’s legal limits are not health-protective. The EPA has not set a new tap water standard in almost 20 years, and some standards are more than 40 years old.

Contaminants Detected

Arsenic

Potential Effect: cancer250x EWG'S HEALTH GUIDELINE
THIS UTILITY1.000 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 250 times above EWG's Health Guideline.

EWG Health Guideline

0.004 ppb or less

This Utility

1 ppb

Legal Limit

10 ppb

National Average

0.647 ppb

State Average

2.66 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 icon

Agriculture

industry icon

Industry

naturally occuring icon

Naturally Occurring

Filtering Options

reverse osmosis icon

Reverse Osmosis

ion exchange icon

Ion Exchange

Radium, combined (-226 & -228)

Potential Effect: cancer2.1x EWG'S HEALTH GUIDELINE
THIS UTILITY0.10 pCi/L
EWG HEALTH GUIDELINE0.05 pCi/L
LEGAL LIMIT5 pCi/L
DETAILS
X

Radium, combined (-226 & -228)

more about
this contaminant

Radium is a radioactive element that causes bone cancer and other cancers. It can occur naturally in groundwater, and oil and gas extraction activities such as hydraulic fracturing can elevate concentrations.

Radium, combined (-226 & -228) was found at 2.1 times above EWG's Health Guideline.

EWG Health Guideline

0.05 pCi/L or less

This Utility

0.1 pCi/L

Legal Limit

5 pCi/L

National Average

0.46 pCi/L

State Average

0.45 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

EWG applied the health guideline of 0.05 pCi/L, defined by the California Office of Environmental Health Hazard Assessment as a public health goal for radium-226, to radium-226 and radium-228 combined. This health guideline protects against cancer.

Pollution Sources

industry icon

Industry

naturally occuring icon

Naturally Occurring

Filtering Options

reverse osmosis icon

Reverse Osmosis

ion exchange icon

Ion Exchange

Total trihalomethanes (TTHMs)†

Potential Effect: cancer8.2x EWG'S HEALTH GUIDELINE
THIS UTILITY1.23 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 8.2 times above EWG's Health Guideline.

EWG Health Guideline

0.15 ppb or less

This Utility

1.23 ppb

Legal Limit

80 ppb

National Average

29.7 ppb

State Average

10.7 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

water treatment icon

Treatment Byproducts

Filtering Options

carbon filter icon

Activated Carbon

reverse osmosis icon

Reverse Osmosis

Includes 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


Preston, City of compliance with legally mandated federal standards:

  • From April 2019 to March 2021, Preston, City of complied with health-based drinking water standards.
  • 12 QUARTERS
    in violation of any federal drinking water standard from April 2019 to March 2021

Information in this section on Preston, City of 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
Radium, combined (-226 & -228)
Total trihalomethanes (TTHMs)
OTHER CONTAMINANTS
DETECTED
Barium
Chloroform
Uranium, combined (pCi/L)

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