Montana Drinking Water Compliance Records
803 water systems serving 790,601 people. 29,601 historical EPA violation records in the Q2 2026 snapshot.
TapScore Compliance-History Grades
A
503
63%
B
150
19%
C
114
14%
D
26
3%
F
10
1%
803
Water Systems
790,601
Population Served
29,601
Historical Records
2,108
Health-Based (All Years)
Systems With the Most Recent EPA Records
BITTERROOT GATEWAY MB PK LOLO
130 served410 historical records109 recent
C
MONTANA STATE PRISON
2,100 served110 historical records96 recent
C
WIBAUX TOWN OF
550 served119 historical records88 recent
D
RIDERS TRAILER COURT
100 served137 historical records67 recent
C
DENTON TOWN OF
255 served109 historical records63 recent
F
WINNETT TOWN OF
187 served133 historical records55 recent
C
BAKER CITY OF
1,858 served132 historical records51 recent
C
GORE HILL COUNTY WATER DIST
500 served95 historical records50 recent
C
HARLEM CITY OF
820 served179 historical records50 recent
F
WINIFRED TOWN OF
274 served120 historical records50 recent
D
Large Systems With No Recent Records
BILLINGS CITY OF
114,000 served4 historical records
A
MISSOULA WATER
68,200 served5 historical records
A
GREAT FALLS CITY OF
60,000 served10 historical records
A
BOZEMAN CITY OF
56,000 served9 historical records
A
KALISPELL PUBLIC WORKS
25,000 served66 historical records
A
BELGRADE CITY OF
10,460 served114 historical records
A
WHITEFISH CITY OF
10,418 served36 historical records
A
WEST YELLOWSTONE TOWN OF
9,899 served88 historical records
A
LIVINGSTON CITY OF
7,500 served319 historical records
A
BIGFORK COUNTY WATER AND SEWER
6,100 served15 historical records
A
Largest Water Systems in Montana
| Water System | Grade | Population | Historical Records |
|---|---|---|---|
| BILLINGS CITY OF | A | 114,000 | 4 |
| MISSOULA WATER | A | 68,200 | 5 |
| GREAT FALLS CITY OF | A | 60,000 | 10 |
| BOZEMAN CITY OF | A | 56,000 | 9 |
| BUTTE SILVERBOW WATER DEPT | C | 33,000 | 78 |
| HELENA WATER SYSTEM | D | 32,091 | 23 |
| KALISPELL PUBLIC WORKS | A | 25,000 | 66 |
| BILLINGS HEIGHTS CO WATER DIST OF | C | 12,000 | 7 |
| BELGRADE CITY OF | A | 10,460 | 114 |
| WHITEFISH CITY OF | A | 10,418 | 36 |
| HAVRE CITY OF | C | 9,921 | 19 |
| WEST YELLOWSTONE TOWN OF | A | 9,899 | 88 |
| MILES CITY CITY OF | D | 9,565 | 20 |
| MALMSTROM AIR FORCE BASE | C | 8,850 | 24 |
| FLATHEAD COUNTY WATER AND SEWER | B | 7,775 | 10 |
| LIVINGSTON CITY OF | A | 7,500 | 319 |
| ANACONDA WATER DEPARTMENT | B | 6,750 | 42 |
| LAUREL MUNICIPAL WATER SYSTEM | C | 6,339 | 47 |
| BIGFORK COUNTY WATER AND SEWER | A | 6,100 | 15 |
| LEWISTOWN CITY OF | A | 5,923 | 147 |
Contaminants in Montana
Lead in MontanaArsenic in MontanaNitrate in MontanaFluoride in MontanaPFOS in MontanaPFOA in MontanaTHMs in MontanaHAA5 in Montana
Cities in Montana
BILLINGS(52)MISSOULA(81)GREAT FALLS(30)BOZEMAN(38)HELENA(59)KALISPELL(96)BUTTE(2)BELGRADE(16)WHITEFISH(20)HAVRE(8)MILES CITY(5)WEST YELLOWSTONE(4)ANACONDA(7)COLUMBIA FALLS(29)MALMSTROM AIR FORCE BASE(1)BIGFORK(17)LIVINGSTON(8)GLENDIVE(9)EAST HELENA(21)LAUREL(6)HAMILTON(16)BIG SKY(16)POLSON(11)LEWISTOWN(5)LIBBY(9)SIDNEY(4)DILLON(8)DEER LODGE(2)SHELBY(6)CUT BANK(11)LOLO(7)GLASGOW(3)CULBERTSON(2)HARDIN(3)CONRAD(5)RONAN(5)EUREKA(7)ROUNDUP(3)STEVENSVILLE(9)TROY(4)MANHATTAN(8)TOWNSEND(4)COLSTRIP(1)HARLOWTON(4)THOMPSON FALLS(4)LAKESIDE(11)FORSYTH(1)RED LODGE(3)BLACK EAGLE(4)PABLO(1)FRENCHTOWN(8)COLUMBUS(5)BAKER(3)CHOTEAU(3)THREE FORKS(1)MALTA(2)BIG TIMBER(3)HINGHAM(1)CHESTER(8)PLENTYWOOD(1)PLAINS(1)FORT BENTON(3)LINCOLN(4)WEST GLACIER(3)OREM(3)ENNIS(2)SEELEY LAKE(1)WHITEHALL(1)VIRGINIA CITY(1)CLANCY(9)SOMERS(5)BOULDER(1)CHINOOK(2)PHILIPSBURG(1)FORT HARRISON(1)SUPERIOR(2)WORDEN(2)GARDINER(5)FAIRFIELD(2)HUNGRY HORSE(1)DARBY(2)ABSAROKEE(1)WHITE SULPHUR SPRINGS(2)GALLATIN GATEWAY(7)ASHLAND(2)SUNBURST(5)SCOBEY(1)CIRCLE(2)FAIRVIEW(1)DALLAS(4)FORT PECK(2)BRADY(2)BALLANTINE(2)HARLEM(2)VALIER(4)BOCA RATON(1)BRIDGER(2)PINESDALE(1)ST IGNATIUS(2)POWER(3)