Know Your Environment. Protect Your Health.

UTILITY

Skyline Water System Inc.

location

Grant County, Washington

serves

293

source

Groundwater

data

2018-2023

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 Washington State Department of Health, 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 compliance with federal health-based drinking water standards.

Contaminants Detected

Nitrate

Potential Effect: cancer

This Utility: 0.825 ppm

5.9x

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 5.9 times above EWG's Health Guideline.

EWG Health Guideline

0.14 ppm or less

This Utility

0.825 ppm

Legal Limit

10 ppm

National Average

0.824 ppm

State Average

0.848 ppm

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 million

Pollution Sources

Agriculture

Runoff & Sprawl

Naturally Occurring

Filtering Options

Reverse Osmosis

Ion Exchange

Radium, combined (-226 and -228)

Potential Effect: cancer

This Utility: 1.93 pCi/L

39x

EWG's Health Guideline: 0.05 pCi/L

Radium, combined (-226 and -228)

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 and -228) was found at 39 times above EWG's Health Guideline.

EWG Health Guideline

0.05 pCi/L or less

This Utility

1.93 pCi/L

Legal Limit

5 pCi/L

National Average

0.33 pCi/L

State Average

0.27 pCi/L

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.

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 liter

Pollution Sources

Industry

Naturally Occurring

Filtering Options

Reverse Osmosis

Ion Exchange

Total trihalomethanes (TTHMs)

Potential Effect: cancer

This Utility: 0.465 ppb

3.1x

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 3.1 times above EWG's Health Guideline.

EWG Health Guideline

0.15 ppb or less

This Utility

0.465 ppb

Legal Limit

80 ppb

National Average

29.1 ppb

State Average

18 ppb

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 billion

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Trichloroethylene

Potential Effect: harm to the developing fetus and damage to the immune system

This Utility: 1.37 ppb

3.4x

EWG's Health Guideline: 0.4 ppb

Trichloroethylene

Trichloroethylene, an industrial solvent and common groundwater pollutant, damages the immune system, harms the developing fetus and causes cancer.

Trichloroethylene was found at 3.4 times above EWG's Health Guideline.

EWG Health Guideline

0.4 ppb or less

This Utility

1.37 ppb

Legal Limit

5 ppb

National Average

0.0154 ppb

State Average

0.015 ppb

Health Risks

The EWG Health Guideline of 0.4 ppb for trichloroethylene was defined by the state of Minnesota as health risk limit, the concentration of a contaminant that can be consumed with little or no risk to health. This health guideline protects against harm to the developing fetus and damage to the immune system.

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 billion

Pollution Sources

Industry

Filtering Options

Activated Carbon

Reverse Osmosis

Includes 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.

1,2,4-Trimethylbenzene

This Utility: 4.12 ppb

No EWG Health Guideline

1,2,4-Trimethylbenzene

1,2,4-Trimethylbenzene is a chemical intermediate, industrial solvent and component of gasoline, coal tar and petroleum products. In laboratory animal studies, it harms the adrenal glands.

How your levels compare

This Utility

4.12 ppb

National Average

0.000939 ppb

State Average

0.000172 ppb

EWG Health Guideline

Not yet determined

Legal Limit

None

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 billion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

1,3,5-Trimethylbenzene

This Utility: 1.45 ppb

No EWG Health Guideline

1,3,5-Trimethylbenzene

1,3,5-trimethylbenzene is a neurotoxic, volatile chemical found in gasoline, and used as a solvent and paint thinner.

How your levels compare

This Utility

1.45 ppb

National Average

0.000263 ppb

State Average

0.00006 ppb

EWG Health Guideline

Not yet determined

Legal Limit

None

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 billion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Bromoform

This Utility: 0.136 ppb

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.

How your levels compare

EWG Health Guideline

0.5 ppb or less

This Utility

0.136 ppb

National Average

1.44 ppb

State Average

0.267 ppb

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 .

Legal Limit

None

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 billion

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Chloroform

This Utility: 0.236 ppb

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.

How your levels compare

EWG Health Guideline

0.4 ppb or less

This Utility

0.236 ppb

National Average

16.2 ppb

State Average

14.6 ppb

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.

Legal Limit

None

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 billion

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Chloromethane

This Utility: 0.122 ppb

EWG's Health Guideline: 2.69 ppb

Chloromethane

Chloromethane is an industrial solvent, aerosol propellant and a refrigerant. It also forms as a byproduct of water disinfection. The EPA classifies chloromethane as possibly carcinogenic to humans.

How your levels compare

EWG Health Guideline

2.69 ppb or less

This Utility

0.122 ppb

National Average

0.0113 ppb

State Average

0.00867 ppb

Health Risks

The EWG Health Guideline of 2.69 ppb for chloromethane was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against cancer.

Legal Limit

None

Understanding the Data

The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2023.

ppb = parts per billion

Pollution Sources

Industry

Treatment Byproducts

Naturally Occurring

Filtering Options

Activated Carbon

Reverse Osmosis

Ethylbenzene

This Utility: 0.195 ppb

EWG's Health Guideline: 300 ppb

Ethylbenzene

Ethylbenzene, a component of petroleum, is a volatile cancer-causing chemical primarily used for production of plastics and rubber. Ethylbenzene is also released from gasoline fuel emissions.

How your levels compare

EWG Health Guideline

300 ppb or less

This Utility

0.195 ppb

Legal Limit

700 ppb

National Average

0.00591 ppb

State Average

0.00608 ppb

Health Risks

The EWG Health Guideline of 300 ppb for ethylbenzene 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 harm to internal organs.

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 billion

Pollution Sources

Agriculture

Industry

Filtering Options

Activated Carbon

Reverse Osmosis

Isopropylbenzene

This Utility: 0.263 ppb

No EWG Health Guideline

Isopropylbenzene

Isopropylbenzene, also called cumene, is an intermediate in industrial chemical production, and is also used as a thinner for paints and enamels. The National Toxicology Program classifies isopropylbenzene as a "reasonably anticipated" human carcinogen.

How your levels compare

This Utility

0.263 ppb

National Average

0.000051 ppb

State Average

0.000006 ppb

EWG Health Guideline

Not yet determined

Legal Limit

None

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 billion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Manganese

This Utility: 7.60 ppb

EWG's Health Guideline: 100 ppb

Manganese

Manganese is a naturally occurring element that is common in food and drinking water. Excessive manganese exposures may impair children's attention, memory and intellectual capacity. Click here to read more about manganese.

How your levels compare

EWG Health Guideline

100 ppb or less

This Utility

7.6 ppb

National Average

8.66 ppb

State Average

11.2 ppb

Health Risks

The EWG Health Guideline of 100 ppb for manganese was defined by the state of Minnesota as a health risk limit, the concentration of a contaminant that can be consumed with little or no risk to health. This health guideline protects against harm to the brain and nervous system.

Legal Limit

None

Understanding the Data

The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2023.

ppb = parts per billion

Pollution Sources

Industry

Naturally Occurring

Filtering Options

Ion Exchange

n-Butylbenzene

This Utility: 0.675 ppb

No EWG Health Guideline

n-Butylbenzene

n-Butylbenzene is an industrial chemical.

How your levels compare

This Utility

0.675 ppb

National Average

0.000101 ppb

State Average

0.00003 ppb

EWG Health Guideline

Not yet determined

Legal Limit

None

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 billion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

n-Propylbenzene

This Utility: 0.552 ppb

No EWG Health Guideline

n-Propylbenzene

n-Propylbenzene is a constituent of petroleum and coal, used for chemical manufacturing and in textile dyeing and printing.

How your levels compare

This Utility

0.552 ppb

National Average

0.000208 ppb

State Average

0.000023 ppb

EWG Health Guideline

Not yet determined

Legal Limit

None

Understanding the Data

The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2023.

ppb = parts per billion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

p-Isopropyltoluene

This Utility: 0.375 ppb

No EWG Health Guideline

p-Isopropyltoluene

p-Isopropyltoluene is a volatile solvent derived from coal distillation and petrochemical processing.

How your levels compare

This Utility

0.375 ppb

National Average

0.000026 ppb

State Average

0.000017 ppb

EWG Health Guideline

Not yet determined

Legal Limit

None

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 billion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

sec-Butylbenzene

This Utility: 0.242 ppb

No EWG Health Guideline

sec-Butylbenzene

sec-Butylbenzene is an industrial chemical.

How your levels compare

This Utility

0.242 ppb

National Average

0.0157 ppb

State Average

0.000008 ppb

EWG Health Guideline

Not yet determined

Legal Limit

None

Understanding the Data

The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2023.

ppb = parts per billion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Toluene

This Utility: 0.490 ppb

EWG's Health Guideline: 150 ppb

Toluene

Toluene is a volatile solvent that harms the nervous and immune systems, damages the liver and may increase the risk of miscarriage and birth defects.

How your levels compare

EWG Health Guideline

150 ppb or less

This Utility

0.49 ppb

Legal Limit

1,000 ppb

National Average

0.00604 ppb

State Average

0.00152 ppb

Health Risks

The EWG Health Guideline of 150 ppb for toluene 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 harm to internal organs.

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 billion

Pollution Sources

Industry

Filtering Options

Activated Carbon

Reverse Osmosis

Xylenes (total)

This Utility: 2.77 ppb

EWG's Health Guideline: 1,800 ppb

Xylenes (total)

Xylenes are solvents used in industrial and consumer products, such as cleaning agents and paint thinners. Xylenes cause nervous system damage and may harm developing fetuses.

How your levels compare

EWG Health Guideline

1,800 ppb or less

This Utility

2.77 ppb

Legal Limit

10,000 ppb

National Average

0.059 ppb

State Average

0.154 ppb

Health Risks

The EWG Health Guideline of 1,800 ppb for xylenes 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 harm to the brain and nervous system.

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 billion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Includes chemicals detected in 2021-2023 for which annual utility averages were lower than an EWG-selected health guideline established by a federal or state public health authority.

Other Contaminants Tested

Find A Filter

Utility: 

Skyline Water System Inc.
view utility

Carbon Filters

FILTERS 2 contaminants exceeding guidelines (+13 others)

Can reduce the levels of many common contaminants.

pros

  • Lower upfront cost
  • Reduced maintenance

cons

  • Does not remove all contaminants

Reverse Osmosis

FILTERS 4 contaminants exceeding guidelines (+13 others)

Can reduce the levels of many common contaminants.

pros

  • Most effective

cons

  • Higher upfront cost
  • Requires more maintenance
  • Wastes water

Other Considerations

Ion Exchange

Pros: Softens hard water, Reduces some contaminants

Cons: Doesn’t remove all contaminants

Whole-House Filters

Pros: Useful for reducing radiologicals and TCE

Cons: Expensive to install and maintain, Risk of bacterial contamination

Distillation

Pros: Removes heavy metals and harmful microbes

Cons: Does not reduce most contaminants

Explore filter options for each contaminant. See which technologies are effective at reducing specific contaminants to help you make an informed decision on the best water treatment solution for your needs.

CONTAMINANTS ABOVE HEALTH GUIDELINES activated carbon reverse osmosis ion exchange
Nitrate
Radium, combined (-226 & -228)
Total trihalomethanes (TTHMs)
Trichloroethylene
OTHER CONTAMINANTS DETECTED activated carbon reverse osmosis ion exchange
1,2,4-Trimethylbenzene
1,3,5-Trimethylbenzene
Bromoform
Chloroform
Chloromethane
Ethylbenzene
Isopropylbenzene
Manganese
n-Butylbenzene
n-Propylbenzene
p-Isopropyltoluene
sec-Butylbenzene
Toluene
Xylenes (total)