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 Montana 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 compliance with 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: 0.333 ppb
Legal Limit: 10 ppb
83x
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 83 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
Bromochloroacetic acid
Potential Effect:

This Utility: 2.55 ppb
No Legal Limit
127x
EWG's Health Guideline: 0.02 ppb
Bromochloroacetic acid
Bromochloroacetic acid is formed when chlorine or other disinfectants are used to treat drinking water. Bromochloroacetic acid and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy.
Bromochloroacetic acid was found at 127 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 0.02 ppb for bromochloroacetic acid was defined in a peer-reviewed scientific study by EWG and represents a on-in-a-million lifetime cancer risk level. 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 2021-2023.
ppb = parts per billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Bromodichloromethane
Potential Effect: cancer

This Utility: 7.26 ppb
No Legal Limit
121x
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 121 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.
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 billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Chloroform
Potential Effect: cancer

This Utility: 21.6 ppb
No Legal Limit
54x
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 54 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.
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 billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Dibromoacetic acid
Potential Effect:

This Utility: 0.348 ppb
No Legal Limit
12x
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 12 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
National Average
State Average
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 billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Dibromochloromethane
Potential Effect: cancer

This Utility: 1.50 ppb
No Legal Limit
15x
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 15 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.
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 billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Dichloroacetic acid
Potential Effect: cancer

This Utility: 11.2 ppb
No Legal Limit
56x
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.
Dichloroacetic acid was found at 56 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
National Average
State Average
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 billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Haloacetic acids (HAA5)
Potential Effect: cancer

This Utility: 26.5 ppb
Legal Limit: 60 ppb
265x
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 265 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 and nitrite
Potential Effect: cancer

This Utility: 0.447 ppm
Legal Limit: 10 ppm
3.2x
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 3.2 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)
Potential Effect: cancer

This Utility: 30.5 ppb
Legal Limit: 80 ppb
203x
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 203 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
Trichloroacetic acid
Potential Effect: cancer

This Utility: 11.6 ppb
No Legal Limit
116x
EWG's Health Guideline: 0.1 ppb
Trichloroacetic acid
Trichloroacetic 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.
Trichloroacetic acid was found at 116 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 trichloroacetic 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 billionPollution 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.
Lithium

This Utility: 42.8 ppb
No Legal Limit
No EWG Health Guideline
Lithium
Lithium occurs naturally in soil and rock. It is a pollutant from mining and industrial manufacturing of metals, ceramics and batteries. Ingesting too much lithium can lead to symptoms like abdominal pain, diarrhea, nausea and vomiting.
How your levels compare
This Utility
National Average
State Average
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 2018-2024.
ppb = parts per billionPollution Sources
Industry
Runoff & Sprawl
Naturally Occurring
Filtering Options
Reverse Osmosis
Ion Exchange
Manganese

This Utility: 32.0 ppb
No Legal Limit
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
This Utility
National Average
State Average
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 billionPollution Sources
Industry
Naturally Occurring
Filtering Options
Ion Exchange
Monobromoacetic acid

This Utility: 0.267 ppb
No Legal Limit
EWG's Health Guideline: 25 ppb
Monobromoacetic acid
Monobromoacetic 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
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 25 ppb for monobromoacetic 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 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 billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Monochloroacetic acid

This Utility: 2.92 ppb
No Legal Limit
EWG's Health Guideline: 53 ppb
Monochloroacetic acid
Monochloroacetic 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
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 53 ppb for monochloroacetic 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.a public health goal. This health guideline protects against 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 billionPollution Sources
Treatment Byproducts
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
✕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-Dibromo-3-chloropropane (DBCP), 1,2-Dichloroethane, 1,2-Dichloropropane, 1,3,5-Trimethylbenzene, 1,3-Dichloropropane, 1,3-Dichloropropene, 11-chloroeicosafluoro-3-oxaundecane-1-sulfonic aci, 17-beta-Estradiol, 2,2-Dichloropropane, 2,4,5-TP (Silvex), 2,4-D, 2,4-DB, 3-Hydroxycarbofuran, 4,8-dioxa-3H-perfluorononanoic acid (ADONA), 4-Androstene-3,17-dione, 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 (, Alachlor (Lasso), Aldicarb, Aldicarb sulfone, Aldicarb sulfoxide, Aldrin, Antimony, Asbestos, Atrazine, Barium, Benzene, Benzo[a]pyrene, Beryllium, Bromobenzene, Bromochloromethane, Bromoform, Bromomethane, Butachlor, Butanoic acid, 2,2,3,3,4,4-hexafluoro-4-(trifluoro, Cadmium, Carbaryl, Carbofuran, Carbon tetrachloride, Chlordane, Chloroethane, Chloromethane, Chromium (total), cis-1,2-Dichloroethylene, Combined uranium, Cyanide, Dalapon, Di(2-ethylhexyl) adipate, Di(2-ethylhexyl) phthalate, Dibromomethane, Dicamba, Dichlorodifluoromethane, Dichloromethane (methylene chloride), Dichlorprop, Dieldrin, Dinoseb, Diquat, Endothall, Endrin, Equilin, Estriol, Estrone, Ethinyl estradiol, Ethylbenzene, Ethylene dibromide, Glyphosate, Heptachlor, Heptachlor epoxide, Hexachlorobenzene (HCB), Hexachlorobutadiene, Hexachlorocyclopentadiene, Hexafluoropropylene oxide dimer acid (HFPO-DA), Isopropylbenzene, Lindane, m-Dichlorobenzene, Mercury (inorganic), Methomyl, Methoxychlor, Metolachlor, Metribuzin, Monochlorobenzene (chlorobenzene), n-Butylbenzene, N-ethyl perfluorooctane sulfonamido acetic acid (N, N-methyl perfluorooctanesulfonamidoacetic acid, n-Propylbenzene, Naphthalene, Nonafluoro-3,6-dioxaheptanoic acid, o-Chlorotoluene, o-Dichlorobenzene, Oxamyl (Vydate), p-Chlorotoluene, p-Dichlorobenzene, p-Isopropyltoluene, Pentachlorophenol, Perfluoro(2-ethoxyethane)sulfonic acid, Perfluorobutane sulfonate (PFBS), Perfluorobutanoic acid (PFBA), Perfluorodecanoic acid (PFDA), Perfluorododecanoic acid (PFDoA), Perfluoroheptane sulfonic acid (PFHpS), Perfluoroheptanoic acid (PFHPA), Perfluorohexane sulfonate (PFHXS), Perfluorohexanoic Acid (PFHxA), Perfluorononanoic acid (PFNA), Perfluorooctane sulfonate (PFOS), Perfluorooctanoic acid (PFOA), Perfluoropentane sulfonic acid (PFPeS), Perfluoropentanoic acid (PFPeA), Perfluorotetradecanoic acid (PFTA), Perfluorotridecanoic acid (PFTrDA), Perfluoroundecanoic acid (PFUnA), Picloram, Polychlorinated biphenyls (PCBs), Propachlor, Propanoic acid, 2,2,3,3-tetrafluoro-3-(trifluorome, Radium, combined (-226 & -228), sec-Butylbenzene, Selenium, Simazine, Styrene, tert-Butylbenzene, Testosterone, Tetrachloroethylene (perchloroethylene), Thallium, Toluene, Toxaphene, trans-1,2-Dichloroethylene, Trichloroethylene, Trichlorofluoromethane, Vinyl chloride, Xylenes (total)
Find A Filter
Utility:
Lockwood Water and Sewer DistrictCarbon Filters
FILTERS 9 contaminants exceeding guidelines (+2 others)
Can reduce the levels of many common contaminants.
pros
- Lower upfront cost
- Reduced maintenance
cons
- Does not remove all contaminants
Reverse Osmosis
FILTERS 11 contaminants exceeding guidelines (+3 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 | |||
| Bromochloroacetic acid | |||
| Bromodichloromethane | |||
| Chloroform | |||
| Dibromoacetic acid | |||
| Dibromochloromethane | |||
| Dichloroacetic acid | |||
| Haloacetic acids (HAA5) | |||
| Nitrate & nitrite | |||
| Total trihalomethanes (TTHMs) | |||
| Trichloroacetic acid | |||
| OTHER CONTAMINANTS DETECTED | activated carbon | reverse osmosis | ion exchange |
| Lithium | |||
| Manganese | |||
| Monobromoacetic acid | |||
| Monochloroacetic acid |
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