Know Your Environment. Protect Your Health.

UTILITY

Hemlock Mutual Water Company

location

Los Angeles County, California

serves

686

source

Groundwater

data

2015-2023

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 California State Water Resources Control Board, 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

Arsenic

Potential Effect: cancer

This Utility: 1.09 ppb

271x

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 271 times above EWG's Health Guideline.

EWG Health Guideline

0.004 ppb or less

This Utility

1.09 ppb

Legal Limit

10 ppb

National Average

0.624 ppb

State Average

0.899 ppb

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 billion

Pollution Sources

Agriculture

Industry

Naturally Occurring

Filtering Options

Reverse Osmosis

Ion Exchange

Bromodichloromethane

Potential Effect: cancer

This Utility: 1.05 ppb

18x

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 18 times above EWG's Health Guideline.

EWG Health Guideline

0.06 ppb or less

This Utility

1.05 ppb

National Average

5.89 ppb

State Average

5.64 ppb

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.

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

Potential Effect: cancer

This Utility: 1.18 ppb

2.9x

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 2.9 times above EWG's Health Guideline.

EWG Health Guideline

0.4 ppb or less

This Utility

1.18 ppb

National Average

16.2 ppb

State Average

10.5 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

Chromium (hexavalent)

Potential Effect: cancer

This Utility: 0.433 ppb

22x

EWG's Health Guideline: 0.02 ppb

Chromium (hexavalent)

Chromium (hexavalent) is a carcinogen that commonly contaminates American drinking water. Chromium (hexavalent) in drinking water may be due to industrial pollution or natural occurrences in mineral deposits and groundwater. Read more about chromium (hexavalent).

Chromium (hexavalent) was found at 22 times above EWG's Health Guideline.

EWG Health Guideline

0.02 ppb or less

This Utility

0.433 ppb

National Average

0.44 ppb

State Average

0.812 ppb

Health Risks

The EWG Health Guideline of 0.02 ppb for chromium (hexavalent) 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.

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

Reverse Osmosis

Ion Exchange

Dibromoacetic acid

Potential Effect:

This Utility: 0.375 ppb

13x

EWG's Health Guideline: 0.03 ppb

Dibromoacetic acid

Dibromoacetic acid, one of the group of five haloacetic acids regulated by federal standards, is formed when chlorine or other disinfectants are used to treat drinking water. Haloacetic acids and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Dibromoacetic acid was found at 13 times above EWG's Health Guideline.

EWG Health Guideline

0.03 ppb or less

This Utility

0.375 ppb

National Average

1.13 ppb

State Average

1.94 ppb

Health Risks

The EWG Health Guideline of 0.03 ppb for dibromoacetic acid was defined by 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

Dibromochloromethane

Potential Effect: cancer

This Utility: 1.28 ppb

13x

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 13 times above EWG's Health Guideline.

EWG Health Guideline

0.1 ppb or less

This Utility

1.28 ppb

National Average

3.55 ppb

State Average

6.38 ppb

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.

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

Haloacetic acids (HAA5)

Potential Effect: cancer

This Utility: 36.2 ppb

362x

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 362 times above EWG's Health Guideline.

EWG Health Guideline

0.1 ppb or less

This Utility

36.2 ppb

Legal Limit

60 ppb

National Average

19.8 ppb

State Average

35.5 ppb

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 billion

Pollution Sources

Treatment Byproducts

Filtering Options

Activated Carbon

Reverse Osmosis

Nitrate

Potential Effect: cancer

This Utility: 1.06 ppm

7.5x

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 7.5 times above EWG's Health Guideline.

EWG Health Guideline

0.14 ppm or less

This Utility

1.06 ppm

Legal Limit

10 ppm

National Average

0.824 ppm

State Average

1.21 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

Perfluorodecanoic acid (PFDA)

Potential Effect:

This Utility: 0.114 ppt

19x

EWG's Health Guideline: 0.006 ppt

Perfluorodecanoic acid (PFDA)

Perfluorodecanoic acid (PFDA) is a member of a group of perfluorinated chemicals used in many consumer products. PFDA and other perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.

Perfluorodecanoic acid (PFDA) was found at 19 times above EWG's Health Guideline.

EWG Health Guideline

0.006 ppt or less

This Utility

0.114 ppt

National Average

0.008 ppt

State Average

0.01 ppt

Health Risks

The EWG Health Guideline of 0.006 ppt for PFDA was defined by EPA's toxicity value published in the Integrated Risk Information System’s toxicological review. This health guideline protects against harm to the immune system and harm to fetal growth and child 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 2018-2024.

ppt = parts per trillion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Perfluorohexane sulfonate (PFHXS)

Potential Effect:

This Utility: 2.36 ppt

2,363x

EWG's Health Guideline: 0.001 ppt

Perfluorohexane sulfonate (PFHXS)

Perfluorohexane sulfonate is a member of a group of perfluorinated chemicals used in many consumer products. Perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.

Perfluorohexane sulfonate (PFHXS) was found at 2,363 times above EWG's Health Guideline.

EWG Health Guideline

0.001 ppt or less

This Utility

2.36 ppt

Legal Limit

10 ppt

National Average

0.523 ppt

State Average

0.755 ppt

Health Risks

The EWG Health Guideline of 0.001 ppt for perfluorohexane sulfonate was defined by EPA's toxicity value published in the Integrated Risk Information System's toxicological review. This health guideline harm to the developing immune system.

Understanding the Data

The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2024.

ppt = parts per trillion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Perfluorooctane sulfonate (PFOS)

Potential Effect:

This Utility: 10.8 ppt

36x

EWG's Health Guideline: 0.3 ppt

Perfluorooctane sulfonate (PFOS)

Perfluorooctane sulfonate (PFOS) is a member of a group of perfluorinated chemicals used in many consumer products. PFOS and other perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.

Perfluorooctane sulfonate (PFOS) was found at 36 times above EWG's Health Guideline.

EWG Health Guideline

0.3 ppt or less

This Utility

10.8 ppt

Proposed Legal Limit

4 ppt

National Average

1.15 ppt

State Average

1.5 ppt

Health Risks

The EWG Health Guideline of 0.3 ppt for PFOS was defined by EPA's final toxicity value from the Office of Water’s Final Human Health Toxicity Assessment. This health guideline protects againat cardiovascular harm and harm to fetal growth.

Understanding the Data

The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2024.

ppt = parts per trillion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Perfluorooctanoic acid (PFOA)

Potential Effect: cancer

This Utility: 2.95 ppt

33x

EWG's Health Guideline: 0.09 ppt

Perfluorooctanoic acid (PFOA)

Perfluorooctanoic acid (PFOA) is a member of a group of perfluorinated chemicals used in many consumer products. PFOA and other perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.

Perfluorooctanoic acid (PFOA) was found at 33 times above EWG's Health Guideline.

EWG Health Guideline

0.09 ppt or less

This Utility

2.95 ppt

Proposed Legal Limit

4 ppt

National Average

0.796 ppt

State Average

0.771 ppt

Health Risks

The EWG Health Guideline of 0.09 ppt for PFOA was was defined by EPA's final toxicity value from the Office of Water’s Final Human Health Toxicity Assessment. This health guideline protects againat cardiovascular harm and harm to fetal growth.

Understanding the Data

The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2024.

ppt = parts per trillion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Perfluoropentane sulfonic acid (PFPeS)

Potential Effect:

This Utility: 4.38 ppt

4.4x

EWG's Health Guideline: 1 ppt

Perfluoropentane sulfonic acid (PFPeS)

Perfluoropentane sulfonic acid (PFPeS) is a member of a group of perfluorinated chemicals used in many consumer products. PFPeS and other perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.

Perfluoropentane sulfonic acid (PFPeS) was found at 4.4 times above EWG's Health Guideline.

EWG Health Guideline

1 ppt or less

This Utility

4.38 ppt

National Average

0.026 ppt

State Average

0.043 ppt

Health Risks

The EWG Health Guideline of 1 ppt for PFPeS was defined by EWG as based on studies by Phillipe Grandjean of Harvard University and many other independent researchers who found reduced effectiveness of vaccines and adverse impacts on mammary gland development from exposure to PFOA and PFOS, the two PFAS most widely detected in drinking water.

Legal Limit

None

Understanding the Data

The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2018-2024.

ppt = parts per trillion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Total trihalomethanes (TTHMs)

Potential Effect: cancer

This Utility: 3.85 ppb

26x

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 26 times above EWG's Health Guideline.

EWG Health Guideline

0.15 ppb or less

This Utility

3.85 ppb

Legal Limit

80 ppb

National Average

29.1 ppb

State Average

27.1 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

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.


† 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.

Barium

This Utility: 76.5 ppb

EWG's Health Guideline: 700 ppb

Barium

Barium is a mineral present in rocks, soil and water. High concentrations of barium in drinking water increase the risk of cardiovascular disease and hypertension.

How your levels compare

EWG Health Guideline

700 ppb or less

This Utility

76.5 ppb

Legal Limit

2,000 ppb

National Average

39.5 ppb

State Average

31 ppb

Health Risks

The EWG Health Guideline of 700 ppb for barium was defined by EWG as benchmark that protects against harm to the kidneys and the cardiovascular 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

Naturally Occurring

Filtering Options

Reverse Osmosis

Ion Exchange

Bromoform

This Utility: 0.625 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

0.625 ppb

National Average

1.44 ppb

State Average

3.85 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

Dichloroacetic acid

This Utility: 0.300 ppb

EWG's Health Guideline: 0.2 ppb

Dichloroacetic acid

Dichloroacetic acid, one of the group of five haloacetic acids regulated by federal standards, is formed when chlorine or other disinfectants are used to treat drinking water. Haloacetic acids 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

0.2 ppb or less

This Utility

0.3 ppb

National Average

8 ppb

State Average

4.69 ppb

Health Risks

The EWG Health Guideline of 0.2 ppb for dichloroacetic acid was defined by 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 reproduction and child 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

Fluoride

This Utility: 0.160 ppm

No EWG Health Guideline

Fluoride

Fluoride occurs naturally in surface and groundwater and is also added to drinking water by many water systems to prevent cavities and support oral health in people.

In 2015, the Department of Health and Human Services updated its recommendation of an optimal level of 0.7 parts per million, or ppm, added to drinking water based on the health benefits of tooth decay prevention. Studies have shown that fluoride added to community water systems at this level reduces dental cavities, especially in children.

And studies have conclusively shown that fluoride in toothpaste and mouthwash can also provide these benefits.

How your levels compare

This Utility

0.16 ppm

Legal Limit

4 ppm

National Average

0.49 ppm

State Average

0.47 ppm

EWG Health Guideline

Not yet determined

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

Industry

Treatment Byproducts

Naturally Occurring

Filtering Options

Reverse Osmosis

Perfluorobutane sulfonate (PFBS)

This Utility: 2.28 ppt

EWG's Health Guideline: 2,000 ppt

Perfluorobutane sulfonate (PFBS)

Perfluorobutane sulfonate (PFBS) is a member of a group of perfluorinated chemicals used in many consumer products. PFOS and other perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.

How your levels compare

EWG Health Guideline

2,000 ppt or less

This Utility

2.28 ppt

National Average

0.679 ppt

State Average

0.415 ppt

Health Risks

The EWG Health Guideline of 2,000 ppt for perfluorobutane sulfonate was defined by EPA’s Human Health toxicity value. This health guideline hormone disruption and harm to fetal growth and child 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 2013-2024.

ppt = parts per trillion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Perfluorobutanoic Acid (PFBA)

This Utility: 6.18 ppt

EWG's Health Guideline: 1,000 ppt

Perfluorobutanoic Acid (PFBA)

Perfluorobutanoic acid (PFBA) is a member of a group of perfluorinated chemicals used in many consumer products. PFOS and other perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.

How your levels compare

EWG Health Guideline

1,000 ppt or less

This Utility

6.18 ppt

National Average

1.64 ppt

State Average

0.628 ppt

Health Risks

The EWG Health Guideline of 1,000 ppt for perfluorobutanoic acid was defined by EPA's recommended application of the toxicity value for PFHxA published in the Integrated Risk Information System’s toxicological review. This health guideline protects against harm to fetal growth and child 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 2018-2024.

ppt = parts per trillion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Perfluoroheptanoic acid (PFHPA)

This Utility: 1.59 ppt

EWG's Health Guideline: 1,000 ppt

Perfluoroheptanoic acid (PFHPA)

Perfluoroheptanoic acid is a member of a group of perfluorinated chemicals used in many consumer products. Perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.

How your levels compare

EWG Health Guideline

1,000 ppt or less

This Utility

1.59 ppt

National Average

0.249 ppt

State Average

0.168 ppt

Health Risks

The EWG Health Guideline of 1,000 ppt for perfluoroheptanoic acid was defined by EPA's recommended application of the toxicity value for PFHxA published in the Integrated Risk Information System’s toxicological review. This health guideline harm to fetal growth and child 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 2013-2024.

ppt = parts per trillion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Perfluorohexanoic Acid (PFHxA)

This Utility: 4.90 ppt

EWG's Health Guideline: 1,000 ppt

Perfluorohexanoic Acid (PFHxA)

Perfluorohexanoic acid is a member of a group of perfluorinated chemicals used in many consumer products. Perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.

How your levels compare

EWG Health Guideline

1,000 ppt or less

This Utility

4.9 ppt

National Average

1.05 ppt

State Average

0.743 ppt

Health Risks

The EWG Health Guideline of 1,000 ppt for perfluorohexanoic acid was defined by EPA's toxicity value published in the Integrated Risk Information System's toxicological review. This health guideline protects against harm to fetal growth and child 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 2018-2024.

ppt = parts per trillion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Perfluoropentanoic Acid (PFPeA)

This Utility: 9.95 ppt

EWG's Health Guideline: 1,000 ppt

Perfluoropentanoic Acid (PFPeA)

Perfluoropentanoic Acid (PFPeA) is a member of a group of perfluorinated chemicals used in many consumer products. PFOS and other perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.

How your levels compare

EWG Health Guideline

1,000 ppt or less

This Utility

9.95 ppt

National Average

1.28 ppt

State Average

0.786 ppt

Health Risks

The EWG Health Guideline of 1,000 ppt for PFPeA was defined by EPA's recommended application of the toxicity value for PFHxA published in the Integrated Risk Information System’s toxicological review. This health guideline protects against harm to fetal growth and child 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 2018-2024.

ppt = parts per trillion

Pollution Sources

Industry

Runoff & Sprawl

Filtering Options

Activated Carbon

Reverse Osmosis

Strontium

This Utility: 0.325 ppb

EWG's Health Guideline: 1,500 ppb

Strontium

Strontium is a metal that accumulates in the bones. Radioactive strontium-90 can cause bone cancer and leukemia, and any form of strontium at high doses can harm bone health.

How your levels compare

EWG Health Guideline

1,500 ppb or less

This Utility

0.325 ppb

National Average

0.488 ppb

State Average

0.695 ppb

Health Risks

The EWG Health Guideline of 1,500 ppb for strontium was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against harm to bones.

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

Reverse Osmosis

Ion Exchange

Uranium

This Utility: 0.31 pCi/L

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.

How your levels compare

EWG Health Guideline

0.43 pCi/L or less

This Utility

0.31 pCi/L

Legal Limit

20 pCi/L

National Average

1.03 pCi/L

State Average

1.91 pCi/L

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 liter

Pollution Sources

Industry

Naturally Occurring

Filtering Options

Reverse Osmosis

Ion Exchange

Vanadium

This Utility: 0.810 ppb

EWG's Health Guideline: 21 ppb

Vanadium

Vanadium is a metal used in steels and other alloys. People are commonly exposed to vanadium in water and food. Excessive exposure can be toxic during pregnancy and childhood.

How your levels compare

EWG Health Guideline

21 ppb or less

This Utility

0.81 ppb

National Average

1.54 ppb

State Average

3.25 ppb

Health Risks

The EWG Health Guideline of 21 ppb for vanadium was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against change in blood chemistry.

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

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

Chemicals tested for but not detected:

1,1,1,2-Tetrachloroethane, 1,1,1-Trichloroethane, 1,1,2,2-Tetrachloroethane, 1,1,2-Trichloroethane, 1,1-Dichloroethane, 1,1-Dichloroethylene, 1,1-Dichloropropene, 1,2,3-Trichlorobenzene, 1,2,3-Trichloropropane, 1,2,4-Trichlorobenzene, 1,2,4-Trimethylbenzene, 1,2-Dichloroethane, 1,2-Dichloropropane, 1,3,5-Trimethylbenzene, 1,3-Butadiene, 1,3-Dichloropropane, 1,3-Dichloropropene, 1,4-Dioxane, 11-chloroeicosafluoro-3-oxaundecane-1-sulfonic aci, 2,2-Dichloropropane, 2-Chloroethylvinyl ether, 4,8-dioxa-3H-perfluorononanoic acid (ADONA), 4:2 Fluorotelomer Sulfonic Acid (4:2 FTSA), 6:2 Fluorotelomer Sulfonic Acid (6:2 FTSA), 8:2 Fluorotelomer Sulfonic Acid (8:2 FTSA), 9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid (, Aluminum, Antimony, Benzene, Beryllium, Bromobenzene, Bromochloromethane, Bromomethane, Butanoic acid, 2,2,3,3,4,4-hexafluoro-4-(trifluoro, Cadmium, Carbon tetrachloride, Chlorate, Chlorodifluoromethane, Chloroethane, Chloromethane, Chromium (total), cis-1,2-Dichloroethylene, cis-1,3-Dichloropropene, Cobalt, Cyanide, Di(2-ethylhexyl) phthalate, Dibromomethane, Dichlorodifluoromethane, Dichloromethane (methylene chloride), Ethyl tert-butyl ether, Ethylbenzene, Germanium, Hexachlorobutadiene, Hexafluoropropylene oxide dimer acid (HFPO-DA), Isopropyl ether, Isopropylbenzene, m-Dichlorobenzene, Manganese, Mercury (inorganic), Methyl ethyl ketone, Methyl isobutyl ketone, Molybdenum, Monobromoacetic acid, Monochloroacetic acid, Monochlorobenzene (chlorobenzene), MTBE, n-Butylbenzene, N-ethyl perfluorooctane sulfonamido acetic acid (N, N-methyl perfluorooctanesulfonamidoacetic acid, n-Propylbenzene, Naphthalene, Nitrite, Nonafluoro-3,6-dioxaheptanoic acid, o-Chlorotoluene, o-Dichlorobenzene, p-Chlorotoluene, p-Dichlorobenzene, p-Isopropyltoluene, Perfluoro(2-ethoxyethane)sulfonic acid, Perfluorododecanoic acid (PFDoA), Perfluoroheptane sulfonic acid (PFHpS), Perfluorononanoic acid (PFNA), Perfluorotetradecanoic acid (PFTA), Perfluorotridecanoic acid (PFTrDA), Perfluoroundecanoic acid (PFUnA), Propanoic acid, 2,2,3,3-tetrafluoro-3-(trifluorome, Radium, combined (-226 & -228), sec-Butylbenzene, Selenium, Silver, Styrene, Tellurium, tert-Amyl methyl ether, tert-Butylbenzene, Tetrachloroethylene (perchloroethylene), Thallium, Toluene, trans-1,2-Dichloroethylene, trans-1,3-Dichloropropene, Trichloroacetic acid, Trichloroethylene, Trichlorofluoromethane, Trichlorotrifluoroethane, Vinyl chloride, Xylenes (total)

Find A Filter

Utility: 

Hemlock Mutual Water Company
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Carbon Filters

FILTERS 11 contaminants exceeding guidelines (+7 others)

Can reduce the levels of many common contaminants.

pros

  • Lower upfront cost
  • Reduced maintenance

cons

  • Does not remove all contaminants

Reverse Osmosis

FILTERS 14 contaminants exceeding guidelines (+11 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
Arsenic
Bromodichloromethane
Chloroform
Chromium (hexavalent)
Dibromoacetic acid
Dibromochloromethane
Haloacetic acids (HAA5)
Nitrate
Perfluorodecanoic acid (PFDA)
Perfluorohexane sulfonate (PFHXS)
Perfluorooctane sulfonate (PFOS)
Perfluorooctanoic acid (PFOA)
Perfluoropentane sulfonic acid (PFPeS)
Total trihalomethanes (TTHMs)
OTHER CONTAMINANTS DETECTED activated carbon reverse osmosis ion exchange
Barium
Bromoform
Dichloroacetic acid
Fluoride
Perfluorobutane sulfonate (PFBS)
Perfluorobutanoic acid (PFBA)
Perfluoroheptanoic acid (PFHPA)
Perfluorohexanoic Acid (PFHxA)
Perfluoropentanoic acid (PFPeA)
Strontium
Uranium, combined (pCi/L)
Vanadium
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