The Power of Information

National Drinking Water Database

Combined Uranium (mg/L) in Montana

Uranium is a radioactive element commonly found in most rocks; processed uranium ore is used for power generation and weapons manufacture. [read more]

The Most Polluted Communities in Montana

123 water utilities reported detecting Combined Uranium (mg/L) in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Combined Uranium (mg/L) level

RankSystem Population Served Positive test results of total reported tests Average Level
1Star Meadows
3213 of 1348.15 ppb
(36 to 60 ppb)
2Rocky Mountain Wua
Clancy, MT
3520 of 2545.12 ppb
(0 to 80 ppb)
3Bahny Brae Subdivision
East Helena, MT
354 of 425 ppb
(18 to 29 ppb)
4Forest Park Water Users Association
Clancy, MT
4005 of 520.8 ppb
(6 to 33 ppb)
5Ranch Headquarters
Gardiner, MT
854 of 419 ppb
(19 ppb)
6Bigfork County Water and Sewer
Bigfork, MT
2,5848 of 819 ppb
(5 to 29 ppb)
7Hangmans Tree Wua
Clancy, MT
1584 of 416.25 ppb
(7 to 30 ppb)
8Park Garden Estates
Great Falls, MT
644 of 416.25 ppb
(15 to 17 ppb)
9Worden Ballantine Yellowstone
Worden, MT
6931 of 113 ppb
(13 ppb)
10Wells Garden Estates
Billings, MT
2405 of 512.05 ppb
(10 to 13 ppb)

Health Based Limits for Combined Uranium (mg/L)

Maximum Contaminant Limit Goal (MCLG)A non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.0 ppb
California Public Health GoalsDefined by the State of California Office of Environmental Health Hazard Assessment (OEHHA) as the level of contaminant that is allowed in drinking water. For acutely toxic substances, levels are set at which scientific evidence indicates that no known or anticipated adverse effects on health will occur, plus an adequate margin-of safety. PHGs for carcinogens or other substances which can cause chronic disease shall be based solely on health effects without regard to cost impacts and shall be set at levels which OEHHA has determined do not pose any significant risk to health.0.5 ppb
Drinking Water Equivalent LevelA lifetime exposure concentration protective of adverse, noncarcinogenic health effects, that assumes all of the exposure to a contaminant is from drinking water. Source: U.S. Environmental Protection Agency.20 ppb
Maximum Contaminant Limit (MCL)The enforceable standard which defines the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to health-based limits (Maximum Contaminant Level Goals, or MCLGs) as feasible using the best available analytical and treatment technologies and taking cost into consideration. Source: U.S. Environmental Protection Agency.30 ppb

Violation Summary for Combined Uranium (mg/L) in Montana

Data from the U.S. Environmental Protection Agency includes the following violations of federal standards in Montana since 2004

Violation TypeNumber of Violations
Over maximum contaminant level, Average18
Failure to monitor regularly6
Over maximum contaminant level, Single Sample2