Water Quality in Montana
792 water systems • 193 cities • EPA SDWIS Data
792
Water Systems
20,202
Total Violations
1,220
Health-Based Violations
789,179
Population Served
Overview
Montana has 792 active community water systems serving 789,179 people. These systems have accumulated 20,202 EPA Safe Drinking Water Act violations on record, of which 1,220 are health-based violations (meaning a contaminant exceeded safe levels).
Common contaminants found in violations: Fecal Coliform, Total Haloacetic Acids (HAA5), Disinfection Byproducts, E. coli, TTHM, Chlorine Dioxide, Nitrate-Nitrite, Barium, Haloacetic Acids, Gross Alpha.
Cities with Most Violations in Montana
| # | City | Violations | Health-Based | Water Systems | Population |
|---|---|---|---|---|---|
| 1 | Missoula | 1,134 | 47 | 75 | 79,904 |
| 2 | Bozeman | 969 | 8 | 27 | 66,478 |
| 3 | Kalispell | 778 | 12 | 70 | 39,933 |
| 4 | Helena | 775 | 79 | 38 | 39,611 |
| 5 | Great Falls | 739 | 19 | 18 | 65,624 |
| 6 | Malta | 545 | 0 | 2 | 1,847 |
| 7 | Billings | 496 | 27 | 37 | 139,577 |
| 8 | East Helena | 493 | 12 | 18 | 6,797 |
| 9 | West Yellowstone | 383 | 8 | 4 | 10,239 |
| 10 | Belgrade | 363 | 3 | 13 | 17,300 |
Largest Cities in Montana
| # | City | Population | Violations | Water Systems |
|---|---|---|---|---|
| 1 | Billings | 139,577 | 496 | 37 |
| 2 | Missoula | 79,904 | 1,134 | 75 |
| 3 | Bozeman | 66,478 | 969 | 27 |
| 4 | Great Falls | 65,624 | 739 | 18 |
| 5 | Kalispell | 39,933 | 778 | 70 |
| 6 | Helena | 39,611 | 775 | 38 |
| 7 | Butte | 33,090 | 27 | 2 |
| 8 | Belgrade | 17,300 | 363 | 13 |
| 9 | Whitefish | 14,046 | 35 | 7 |
| 10 | Miles City | 10,388 | 201 | 5 |
All Cities in Montana
| City | Population | Violations | Health Violations | Contaminants |
|---|---|---|---|---|
| Billings | 139,577 | 496 | 27 | Chlorine Dioxide, Disinfection Byproducts, Nitrate-Nitrite |
| Missoula | 79,904 | 1,134 | 47 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| Bozeman | 66,478 | 969 | 8 | Disinfection Byproducts, E. coli |
| Great Falls | 65,624 | 739 | 19 | Barium, Chlorine Dioxide, Disinfection Byproducts +2 more |
| Kalispell | 39,933 | 778 | 12 | Disinfection Byproducts, E. coli |
| Helena | 39,611 | 775 | 79 | Barium, Disinfection Byproducts, E. coli +3 more |
| Butte | 33,090 | 27 | 1 | Fecal Coliform |
| Belgrade | 17,300 | 363 | 3 | Chlorine Dioxide, E. coli, Gross Alpha |
| Whitefish | 14,046 | 35 | 0 | |
| Miles City | 10,388 | 201 | 23 | Fecal Coliform, Lead |
| Havre | 10,263 | 102 | 10 | Bromate, E. coli |
| West Yellowstone | 10,239 | 383 | 8 | E. coli |
| Anaconda | 9,080 | 17 | 1 | Fecal Coliform |
| Malmstrom Air Force Base | 8,850 | 18 | 2 | Total Haloacetic Acids (HAA5) |
| Columbia Falls | 8,805 | 271 | 5 | Chlorine Dioxide, Gross Alpha |
| Bigfork | 8,028 | 358 | 3 | Disinfection Byproducts, Gross Alpha |
| Livingston | 7,850 | 74 | 2 | Disinfection Byproducts |
| Glendive | 6,803 | 339 | 11 | TTHM |
| Laurel | 6,799 | 24 | 3 | E. coli |
| East Helena | 6,797 | 493 | 12 | Barium, Disinfection Byproducts, E. coli |
| Hamilton | 6,458 | 44 | 2 | Disinfection Byproducts |
| Polson | 6,390 | 94 | 1 | E. coli |
| Lewistown | 6,078 | 239 | 38 | Gross Alpha, Nitrate-Nitrite |
| Big Sky | 5,574 | 154 | 2 | Disinfection Byproducts, E. coli |
| Libby | 5,533 | 341 | 19 | Bromate, Chlorine Dioxide, E. coli +2 more |
| Dillon | 5,245 | 186 | 30 | Barium, E. coli |
| Sidney | 5,130 | 75 | 25 | TTHM |
| Deer Lodge | 5,000 | 15 | 0 | |
| Cut Bank | 4,336 | 249 | 2 | Barium, Nitrate-Nitrite |
| Shelby | 4,120 | 85 | 2 | TTHM, Total Haloacetic Acids (HAA5) |
| Glasgow | 3,883 | 237 | 0 | |
| Culbertson | 3,719 | 10 | 0 | |
| Lolo | 3,710 | 25 | 0 | |
| Hardin | 3,550 | 97 | 0 | |
| Ronan | 3,081 | 90 | 4 | E. coli, Fecal Coliform |
| Roundup | 3,075 | 12 | 0 | |
| Conrad | 2,722 | 23 | 0 | |
| Eureka | 2,550 | 72 | 4 | Disinfection Byproducts, E. coli, Fecal Coliform |
| Stevensville | 2,533 | 75 | 1 | Disinfection Byproducts |
| Troy | 2,458 | 56 | 1 | E. coli |
| Orem | 2,417 | 10 | 1 | Fecal Coliform |
| Manhattan | 2,388 | 110 | 2 | Nitrate-Nitrite |
| Colstrip | 2,350 | 28 | 6 | Fecal Coliform, TTHM |
| Forsyth | 2,260 | 2 | 0 | |
| Red Lodge | 2,236 | 163 | 0 | |
| Thompson Falls | 2,230 | 12 | 0 | |
| Townsend | 2,225 | 194 | 0 | |
| Pablo | 2,175 | 21 | 7 | E. coli |
| Baker | 2,055 | 194 | 1 | E. coli |
| Columbus | 2,025 | 96 | 0 | |
| Lakeside | 1,987 | 17 | 0 | |
| Choteau | 1,935 | 37 | 2 | Chlorine Dioxide, Disinfection Byproducts |
| Three Forks | 1,900 | 3 | 1 | Barium |
| Malta | 1,847 | 545 | 0 | |
| Hingham | 1,720 | 2 | 0 | |
| Big Timber | 1,710 | 4 | 2 | Disinfection Byproducts, Fecal Coliform |
| Plains | 1,700 | 2 | 0 | |
| Plentywood | 1,700 | 2 | 0 | |
| Black Eagle | 1,658 | 11 | 5 | Chlorine Dioxide, Total Haloacetic Acids (HAA5) |
| Lincoln | 1,630 | 54 | 0 | |
| West Glacier | 1,620 | 10 | 0 | |
| Ennis | 1,595 | 54 | 0 | |
| Fort Benton | 1,580 | 5 | 0 | |
| Seeley Lake | 1,575 | 5 | 0 | |
| Chester | 1,502 | 112 | 24 | Fecal Coliform, TTHM, Total Haloacetic Acids (HAA5) |
| Virginia City | 1,500 | 38 | 7 | Chlorine Dioxide |
| Whitehall | 1,500 | 101 | 87 | HAA5, Haloacetic Acids |
| Clancy | 1,470 | 160 | 20 | Haloacetic Acids |
| Boulder | 1,400 | 50 | 3 | Disinfection Byproducts, Fecal Coliform |
| Chinook | 1,400 | 12 | 7 | Total Haloacetic Acids (HAA5) |
| Philipsburg | 1,360 | 34 | 25 | Fecal Coliform, Total Haloacetic Acids (HAA5) |
| Fort Smith | 1,325 | 172 | 30 | Chlorine Dioxide, Disinfection Byproducts, Fecal Coliform +1 more |
| Fort Harrison | 1,275 | 16 | 0 | |
| Harlowton | 1,246 | 46 | 1 | Disinfection Byproducts |
| Gardiner | 1,220 | 30 | 1 | Disinfection Byproducts |
| Hungry Horse | 1,135 | 6 | 0 | |
| Darby | 1,125 | 78 | 2 | Disinfection Byproducts |
| Absarokee | 1,100 | 8 | 0 | |
| Superior | 1,100 | 2 | 0 | |
| White Sulphur Springs | 1,087 | 135 | 0 | |
| Ashland | 1,050 | 313 | 61 | Chlorine Dioxide, E. coli, TTHM |
| Somers | 1,035 | 13 | 0 | |
| Scobey | 1,026 | 8 | 0 | |
| Circle | 1,009 | 16 | 0 | |
| Fairview | 1,000 | 13 | 2 | Disinfection Byproducts |
| Sunburst | 973 | 176 | 11 | Chlorine Dioxide |
| Dallas | 950 | 51 | 0 | |
| Brady | 894 | 79 | 17 | TTHM, Total Haloacetic Acids (HAA5) |
| Harlem | 862 | 137 | 68 | Bromate, E. coli, TTHM +1 more |
| Valier | 804 | 59 | 3 | Barium, Nitrate-Nitrite |
| Bridger | 800 | 9 | 0 | |
| Pinesdale | 800 | 12 | 5 | Total Haloacetic Acids (HAA5) |
| St Ignatius | 765 | 67 | 3 | Chlorine Dioxide |
| Power | 764 | 30 | 0 | |
| Warm Springs | 721 | 10 | 0 | |
| Belt | 720 | 19 | 0 | |
| Cascade | 720 | 4 | 1 | Chlorine Dioxide |
| Gallatin Gateway | 720 | 13 | 0 | |
| Fairfield | 718 | 38 | 0 | |
| Huntley | 705 | 23 | 1 | Disinfection Byproducts |
| Ft. Peck | 663 | 6 | 6 | TTHM |
| Joliet | 645 | 32 | 0 | |
| Sheridan | 632 | 11 | 0 | |
| Alberton | 613 | 11 | 2 | E. coli |
| Big Sandy | 608 | 9 | 0 | |
| Hot Springs | 600 | 8 | 0 | |
| Medicine Lake | 600 | 10 | 0 | |
| Vaughn | 585 | 16 | 0 | |
| Wibuax | 550 | 48 | 3 | E. coli, Gross Alpha |
| Fort Shaw | 525 | 23 | 0 | |
| Sand Coulee | 510 | 47 | 2 | Chlorine Dioxide |
| Stanford | 505 | 31 | 1 | Chlorine Dioxide |
| Fromberg | 500 | 179 | 4 | E. coli |
| Bend | 499 | 8 | 1 | E. coli |
| Vancouver | 490 | 5 | 0 | |
| Lodge Grass | 480 | 121 | 0 | |
| Broadus | 450 | 14 | 0 | |
| Charlo | 450 | 17 | 0 | |
| Coram | 450 | 4 | 0 | |
| Froid | 450 | 8 | 0 | |
| Coeur D'Alene | 438 | 7 | 0 | |
| Twin Bridges | 424 | 1 | 0 | |
| Ekalaka | 400 | 20 | 0 | |
| Noxon | 373 | 7 | 0 | |
| Ryegate | 370 | 38 | 8 | Chlorine Dioxide, Disinfection Byproducts |
| Frenchtown | 368 | 13 | 1 | E. coli |
| Jordan | 364 | 210 | 0 | |
| Geraldine | 360 | 39 | 3 | Chlorine Dioxide |
| Highwood | 360 | 280 | 2 | E. coli |
| Port Orchard | 355 | 321 | 3 | Gross Alpha, Nitrate |
| Bainville | 350 | 16 | 1 | Disinfection Byproducts |
| Trout Creek | 350 | 2 | 0 | |
| Martin City | 340 | 1 | 0 | |
| Dutton | 338 | 130 | 2 | E. coli |
| Galata | 325 | 7 | 0 | |
| Broadview | 314 | 16 | 0 | |
| Stockett | 310 | 140 | 1 | Chlorine Dioxide |
| Clyde Park | 300 | 212 | 0 | |
| Cooke City | 300 | 144 | 3 | Fecal Coliform |
| Nashua | 300 | 81 | 3 | TTHM |
| Roberts | 300 | 14 | 1 | Disinfection Byproducts |
| Kodak | 300 | 41 | 5 | Barium |
| Kevin | 290 | 11 | 0 | |
| Lima | 279 | 4 | 0 | |
| Winifred | 274 | 27 | 1 | E. coli |
| Hysham | 262 | 114 | 19 | E. coli, Fecal Coliform |
| Eagle | 260 | 10 | 0 | |
| Denton | 255 | 166 | 155 | Bromate, Chlorine Dioxide, Fecal Coliform +1 more |
| Hinsdale | 250 | 21 | 2 | E. coli |
| Wilsall | 250 | 12 | 4 | Fecal Coliform, Nitrate-Nitrite |
| Hailey | 250 | 286 | 0 | |
| Fort Peck | 240 | 23 | 0 | |
| Neihart | 229 | 14 | 1 | Disinfection Byproducts |
| Carter | 228 | 65 | 9 | Fecal Coliform, TTHM, Total Haloacetic Acids (HAA5) |
| Martinsdale | 225 | 12 | 0 | |
| Zortman | 219 | 30 | 0 | |
| Houston | 216 | 169 | 0 | |
| Belfry | 205 | 5 | 1 | Gross Alpha |
| Basin | 200 | 40 | 3 | Disinfection Byproducts |
| San Diego | 200 | 10 | 2 | Disinfection Byproducts |
| Sweet Grass | 200 | 45 | 2 | TTHM |
| Knoxville | 200 | 1 | 0 | |
| Paradise | 200 | 13 | 0 | |
| Loma | 200 | 4 | 0 | |
| Winnett | 187 | 138 | 0 | |
| Moore | 186 | 8 | 0 | |
| Richey | 180 | 18 | 0 | |
| Saco | 180 | 9 | 0 | |
| Emigrant | 180 | 7 | 0 | |
| Huson | 175 | 47 | 2 | Chlorine Dioxide, Disinfection Byproducts |
| Westby | 172 | 9 | 0 | |
| Melstone | 170 | 19 | 0 | |
| Grass Range | 160 | 30 | 1 | Chlorine Dioxide |
| Rexford | 160 | 3 | 0 | |
| Heron | 154 | 9 | 0 | |
| Lambert | 150 | 53 | 0 | |
| Gildford | 150 | 118 | 0 | |
| Melville | 150 | 61 | 0 | |
| Plevna | 130 | 13 | 0 | |
| Marion | 130 | 7 | 1 | Disinfection Byproducts |
| Judith Gap | 126 | 14 | 0 | |
| Geyser | 125 | 5 | 0 | |
| Yellowtail | 125 | 11 | 0 | |
| Hobson | 125 | 12 | 0 | |
| Dodson | 120 | 164 | 2 | Chlorine Dioxide, E. coli |
| Thoimpson Falls | 115 | 16 | 2 | E. coli |
| Corvallis | 115 | 0 | 0 | |
| Opheim | 111 | 36 | 4 | E. coli |
| Roy | 110 | 20 | 0 | |
| Fortine | 109 | 60 | 1 | Disinfection Byproducts |
| Sun River | 105 | 1 | 0 | |
| Ulm | 105 | 5 | 0 | |
| Bynum | 100 | 40 | 0 |
Data Sources
Drinking water data from the EPA Safe Drinking Water Information System (SDWIS). Only active community water systems (CWS) serving 100+ people are included.