Montana Water Quality
According to EPA Safe Drinking Water Information System (SDWIS), Montana has 818 active community water systems in this extract. PlainEnviro's health-based slice lists 1,604 violation records across 50 systems with at least one such row. These are historical EPA registry counts, not a statewide drinkability score.
Health-based violation records for 818 community water systems in Montana. Source: EPA Safe Drinking Water Information System (SDWIS).
Water Systems with Most Health-Based Records
| # | Water System | Health-Based Records | Health |
|---|---|---|---|
| 1 | FORT BELKNAP AGENCY WATER SYSTEM Harlem | 211 | Yes |
| 2 | DENTON TOWN OF Denton | 162 | Yes |
| 3 | WHITEHALL TOWN OF Whitehall | 91 | Yes |
| 4 | HARLEM CITY OF Harlem | 71 | Yes |
| 5 | BEAVERHEAD JACKSON WATER AND SEWER DIST Jackson | 62 | Yes |
| 6 | ST LABRE INDIAN SCHOOL Ashland | 60 | Yes |
| 7 | CROW AGENCY WATER SYSTEM Crow Agency | 53 | Yes |
| 8 | KING RANCH COLONY Lewistown | 38 | Yes |
| 9 | PHILIPSBURG TOWN OF Philipsburg | 30 | Yes |
| 10 | NCMRWA TIBER SERVICE AREA Helena | 29 | Yes |
| 11 | RICHLAND CO VALLEY VIEW WUA Sidney | 28 | Yes |
| 12 | CLARKS LOOKOUT Dillon | 26 | Yes |
| 13 | BLUE CLOUD SUBDIVISION Helena | 26 | Yes |
| 14 | ARROW CREEK TRAILER COURT Ballantine | 22 | Yes |
| 15 | BLUE SKY HEIGHTS WUA CLANCY Clancy | 20 | Yes |
| 16 | TURNER COLONY Turner | 20 | Yes |
| 17 | RIVERVIEW COLONY Chester | 20 | Yes |
| 18 | HYSHAM TOWN OF Hysham | 19 | Yes |
| 19 | BEE HIVE HOMES MSLA Missoula | 19 | Yes |
| 20 | TIBER COUNTY WATER DISTRICT Brady | 17 | Yes |
| 21 | CRYSTAL SPRINGS WATER SYSTEM Billings | 15 | Yes |
| 22 | PINNACLE ESTATES OF GLENDIVE Glendive | 14 | Yes |
| 23 | PALISADES APARTMENTS Miles City | 13 | Yes |
| 24 | LIBBY CITY OF Libby | 13 | Yes |
| 25 | HELENA WATER SYSTEM Helena | 12 | Yes |
| 26 | MILFORD COLONY INC Wolf Creek | 12 | Yes |
| 27 | ELK CREEK COLONY Augusta | 12 | Yes |
| 28 | BIRNEY VILLAGE Lame Deer | 11 | Yes |
| 29 | COZY NORTHERN HOMES, LLC Livingston | 11 | Yes |
| 30 | CHINOOK CITY OF Chinook | 11 | Yes |
| 31 | TAMARACK COURT Missoula | 11 | Yes |
| 32 | OILMONT COUNTY WATER DISTRICT Sunburst | 11 | Yes |
| 33 | MILES CITY CITY OF Miles City | 10 | Yes |
| 34 | HAVRE CITY OF Havre | 10 | Yes |
| 35 | FISHERMANS VILLAGE SUBDIVISION West Yellowstone | 10 | Yes |
| 36 | WORDEN BALLANTINE YELLOWSTONE Ballantine | 9 | Yes |
| 37 | VIRGINIA CITY WATER DEPT Virginia City | 9 | Yes |
| 38 | RYEGATE TOWN OF Ryegate | 8 | Yes |
| 39 | TWIN HILLS COLONY INC Carter | 8 | Yes |
| 40 | HEART BUTTE SCHOOL Heart Butte | 7 | Yes |
| 41 | SOUTH WIND WATER AND SEWER DISTRICT Great Falls | 7 | Yes |
| 42 | FLAXVILLE TOWN OF Flaxville | 7 | Yes |
| 43 | DUCK CREEK MOBILE HOME PARK Billings | 7 | Yes |
| 44 | PABLO LAKE COUNTY WATER AND SEWER DIST Pablo | 7 | Yes |
| 45 | LAME DEER WATER SYSTEM Lame Deer | 6 | Yes |
| 46 | COLSTRIP CITY OF Colstrip | 6 | Yes |
| 47 | FROMBERG TOWN OF Fromberg | 6 | Yes |
| 48 | WILSALL WATER DISTRICT Wilsall | 6 | Yes |
| 49 | MT ELLIS ACADEMY Bozeman | 6 | Yes |
| 50 | FORT PECK RURAL COUNTY WATER DISTRICT Ft. Peck | 6 | Yes |
Most Common Contaminants in Montana
| Contaminant | Violations | Systems Affected |
|---|---|---|
| TTHM | 307 | 15 |
| Long Term 2 Enhanced Surface Water Treatment Rule | 160 | 10 |
| Groundwater Rule | 148 | 49 |
| Revised Total Coliform Rule | 139 | 69 |
| Total Haloacetic Acids (HAA5) | 135 | 16 |
| Nitrate-Nitrite | 131 | 18 |
| CARBON, TOTAL | 129 | 2 |
| Arsenic | 118 | 10 |
| Combined Uranium | 107 | 2 |
| Surface Water Treatment Rule | 95 | 22 |
| Lead and Copper Rule | 56 | 38 |
| Combined Radium (-226 and -228) | 24 | 1 |
| Interim Enhanced Surface Water Treatment Rule | 22 | 5 |
| Coliform (TCR) | 14 | 11 |
| Fluoride | 13 | 1 |
Cities with Water Quality Issues
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About This Data
Water quality data is from the EPA Safe Drinking Water Information System (SDWIS). Health-based violations include Maximum Contaminant Level (MCL) and Treatment Technique (TT) violations. Only community water systems (CWS) in Montana are included.
Source: U.S. Environmental Protection Agency, SDWIS Federal Reporting Services
Read our methodology - how this data is sourced, computed, and verified.