National Drinking Water Database
Montana
684 systems serving 712,991 people
This drinking water quality report shows results of tests conducted by water utilities in Montana, provided to the Environmental Working Group (EWG) by the Montana Department of Environmental Quality. It is part of EWG's national database that includes 47,667 drinking water utilities and 20 million test results from 45 states and the District of Columbia. Water utilities nationwide detected more than 300 pollutants between 2004 and 2009. More than half of these chemicals are unregulated, legal in any amount. Despite this widespread contamination, the federal government invests few resources in protecting rivers, reservoirs, and groundwater from pollution in the first place. The information below summarizes drinking water quality for this state.
Chemicals |
Water Utilities |
Population Served |
|
|---|---|---|---|
| Detected Chemicals | 67 |
684 |
712,611 |
Exceed health guidelines* | 30 |
657 |
695,214 |
Exceed Legal Limits* | 17 |
81 |
211,553 |
Unregulated chemicals detected | 13 |
142 |
384,277 |
| * Water utilities are noted as exceeding the legal limit if any test is above the maximum contaminant level (MCL). Most MCLs are based on annual averages so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance. | |||
30 Contaminants Exceeding Health Based Limits
Contaminants detected in Montana drinking water above health guidelines, according to an Environmental Working Group analysis of data obtained from state water authorities
| Contaminant | Population |
Number of Systems |
||
|---|---|---|---|---|
| At Any Level | Above Health Limits | At Any Level | Above Health Limits | |
| Total haloacetic acids (HAAs) | 568,674 | 553,372 | 214 | 192 |
| Bromodichloromethane | 541,827 | 541,827 | 171 | 171 |
| Lead (total) | 504,440 | 504,440 | 541 | 541 |
| Dichloroacetic acid | 489,939 | 489,939 | 131 | 131 |
| Arsenic (total) | 456,405 | 456,405 | 241 | 241 |
| Dibromochloromethane | 518,882 | 445,023 | 163 | 156 |
| Total trihalomethanes (TTHMs) | 571,260 | 426,534 | 229 | 130 |
| Chloroform | 545,531 | 406,375 | 183 | 99 |
| Trichloroacetic acid | 462,046 | 332,719 | 136 | 34 |
| Bromoform | 320,003 | 320,003 | 84 | 84 |
Water Utilities in Montana Reporting Chemicals Exceeding Health Guidelines
Water utilities in Montana reporting chemicals exceeding health guidelines, according to an Environmental Working Group analysis of data obtained from state water authorities, include:
| System | Population |
Chemicals tested |
Chemicals found |
Chemicals exceeding health guidelines |
|---|---|---|---|---|
| Town of Hysham | 262 | 119 | 20 | 15 |
| Forest Park Water Users Association | 400 | 123 | 22 | 12 |
| Town of Flaxville | 82 | 115 | 17 | 12 |
| Mountain Water Company | 56,335 | 123 | 21 | 12 |
| Town of Melstone | 170 | 118 | 19 | 12 |
| Laurel Municipal Water System | 6,339 | 106 | 16 | 12 |
| Helena Water System | 31,005 | 117 | 18 | 12 |
| Town of Geraldine | 300 | 29 | 19 | 12 |
| City of Forsyth | 1,944 | 120 | 20 | 12 |
| Town of Chester | 950 | 112 | 20 | 12 |
| Stock Farm The | 100 | 120 | 16 | 11 |
| City of Wolf Point | 3,915 | 117 | 16 | 11 |
| Wilsall Water District | 250 | 114 | 15 | 11 |
| City of Glendive | 4,806 | 112 | 16 | 11 |
| Gardiner Park Co Water Dist | 700 | 112 | 17 | 11 |
| City of Colstrip | 2,000 | 118 | 15 | 11 |
| Brady County Water and Sewer District | 225 | 115 | 18 | 11 |
| Red Cliff Estates Hoa | 36 | 104 | 18 | 10 |
| North Havre County Water Dist | 90 | 106 | 15 | 10 |
| Seville Colony | 110 | 116 | 16 | 10 |
Sources of Montana Drinking Water Contaminants
The contaminants identified in Montana drinking water come from a wide variety of sources, including agriculture, industry, water treatment plants, and polluted storm runoff from urban areas.
Testing Summary for Montana
The federal government has set standards for some of the pollutants found in tap water supplies.
| Contaminants reported as tested by water suppliers in Montana | 152 | |
| Contaminants tested due to federal law: | 86 | |
| Contaminants tested in addition to those required by federal law: | 66 | |
Violation Summary for Montana
Data from the U.S. Environmental Protection Agency includes the following violations of federal standards in Montana since 2004
| Violation Type | Number of Violations |
|---|---|
| Failure to monitor regularly | 3,609 |
| Failure to monitor, Routine Major (Coliform bacteria) | 475 |
| Failure to report information to the public or state agency in the Consumer Confidence Report | 374 |
| Monitoring and Reporting Disinfection Byproduct Rule | 373 |
| Maximum contaminant level, Monthly (Coliform bacteria) | 317 |
| Follow-up and Routine Tap Sampling | 257 |
| Initial Tap Sampling for Lead and Copper | 132 |
| Failure to monitor or report, Routine/Repeat (Indicators of microbial or virus contamination) | 105 |
| Initial Water Quality Parameter Monitoring and Reporting | 92 |
| Over maximum contaminant level, Average | 89 |
| Over maximum contaminant level, Single Sample | 75 |
| Filter Turbidity Reporting | 62 |
| Failure to monitor, Routine Minor (Coliform bacteria) | 55 |
| Treatment Technique (Surface Water Treatment Rule) | 51 |
| Inadequate reporting of information to the public | 50 |
| Excess Turbidity at 0.3 NTU | 47 |
| Excess Turbidity at 1 NTU | 43 |
| Failure to monitor or report, Routine/Repeat (Indicators of microbial or virus contamination) | 33 |
| Failure to monitor, Repeat Major (Coliform bacteria) | 30 |
| Maximum contaminant level, Acute (Coliform bacteria) | 13 |
| Optimal Corrosion Control Treatment Study Recommendation | 12 |
| Public Education | 11 |
| Initial, Follow-up, or Routine Source Water Treatment Monitoring and Reporting | 7 |
| Failure to monitor, Repeat Minor (Coliform bacteria) | 4 |
| Failure to Filter (Surface Water Treatment Rule) | 1 |
| Public Notification Violation for National Primary Drinking Water Regulations | 1 |
| Treatment Technique (Filter Backwash Reporting Rule)? 41 H "Treatment Technique (Surface Water Treatment Rule) | 1 |