Montana Water Systems

Compiled by PlainEnviro Editorial, Environmental Data Editorial Team · July 13, 2026

809 community water systems in Montana, ranked by violation count. Data from EPA Safe Drinking Water Information System (SDWIS).

Water Systems

809

Total Violations

1,430

Health Violations

198 systems

Population Served

814,186

Montana operates 809 community water systems regulated by the EPA Safe Drinking Water Information System (SDWIS) under the Safe Drinking Water Act. Together these utilities serve an estimated 814,186 residents, each filing compliance results with the state's primacy agency and, for federally listed contaminants, with the U.S. Environmental Protection Agency.

Across the state, SDWIS records contain 1,430 total violations, of which 198 systems carry at least one active health-based violation, a Maximum Contaminant Level (MCL) exceedance or treatment-technique failure. That represents roughly 24% of Montana systems.

Violation counts reflect both infrastructure realities and reporting diligence, a state with more small rural systems will accumulate more monitoring-type violations without necessarily delivering worse water. Health-based violations are the stronger safety signal. A past violation does not itself indicate current unsafe water; utilities must notify customers, remediate, and publish an annual Consumer Confidence Report. All numbers below draw directly from the federal SDWIS record.

Which water systems have violations? (138)

#	System Name	City	Source	Violations	Pop. Served	Health
1	DENTON TOWN OF Denton	Denton	Surface Water	155	255	Yes
2	FORT BELKNAP AGENCY WATER SYSTEM Harlem	Harlem	Surface Water	125	2,100	Yes
3	WHITEHALL TOWN OF Whitehall	Whitehall	Groundwater	87	1,500	Yes
4	HARLEM CITY OF Harlem	Harlem	Surface Water	68	820	Yes
5	ST LABRE INDIAN SCHOOL Ashland	Ashland	Groundwater	59	650	Yes
6	CROW AGENCY WATER SYSTEM Crow Agency	Crow Agency	Surface Water	36	1,300	Yes
7	NCMRWA TIBER SERVICE AREA Helena	Helena	Surface Water	29	200	Yes
8	PHILIPSBURG TOWN OF Philipsburg	Philipsburg	Surface Water	25	1,360	Yes
9	BLUE SKY HEIGHTS WUA CLANCY Clancy	Clancy	Groundwater	20	250	Yes
10	RIVERVIEW COLONY Chester	Chester	Surface Water	20	130	Yes
11	HYSHAM TOWN OF Hysham	Hysham	Surface Water	19	262	Yes
12	BEE HIVE HOMES MSLA Missoula	Missoula	Groundwater	19	106	Yes
13	TIBER COUNTY WATER DISTRICT Brady	Brady	Surface Water	17	750	Yes
14	CRYSTAL SPRINGS WATER SYSTEM Billings	Billings	Groundwater	15	225	Yes
15	HELENA WATER SYSTEM Helena	Helena	Surface Water	12	32,091	Yes
16	LIBBY CITY OF Libby	Libby	Surface Water	12	4,892	Yes
17	OILMONT COUNTY WATER DISTRICT Sunburst	Sunburst	Groundwater	11	300	Yes
18	BIRNEY VILLAGE Lame Deer	Lame Deer	Groundwater	11	96	Yes
19	HAVRE CITY OF Havre	Havre	Surface Water	10	9,921	Yes
20	MILES CITY CITY OF Miles City	Miles City	Surface Water	10	9,565	Yes
21	WORDEN BALLANTINE YELLOWSTONE Fort Smith	Fort Smith	Surface Water	9	800	Yes
22	RYEGATE TOWN OF Ryegate	Ryegate	Groundwater	8	270	Yes
23	PABLO LAKE COUNTY WATER AND SEWER DIST Pablo	Pablo	Groundwater	7	2,175	Yes
24	VIRGINIA CITY WATER DEPT Virginia City	Virginia City	Groundwater	7	1,500	Yes
25	CHINOOK CITY OF Chinook	Chinook	Surface Water	7	1,300	Yes
26	HEART BUTTE SCHOOL Heart Butte	Heart Butte	Surface Water	7	250	Yes
27	SOUTH WIND WATER AND SEWER DISTRICT Great Falls	Great Falls	Groundwater	7	200	Yes
28	LAME DEER WATER SYSTEM Lame Deer	Lame Deer	Groundwater	6	2,605	Yes
29	COLSTRIP CITY OF Colstrip	Colstrip	Surface Water	6	2,350	Yes
30	FORT PECK RURAL COUNTY WATER DISTRICT Ft. Peck	Ft. Peck	Surface Water	6	663	Yes
31	MT ELLIS ACADEMY Bozeman	Bozeman	Groundwater	6	106	Yes
32	GREAT FALLS CITY OF Great Falls	Great Falls	Surface Water	5	60,000	Yes
33	PINESDALE TOWN OF Pinesdale	Pinesdale	Surface Water	5	800	Yes
34	BUSBY COMMUNITY WATER SYSTEM Lame Deer	Lame Deer	Groundwater	5	535	Yes
35	COZY NORTHERN HOMES, LLC Livingston	Livingston	Groundwater	5	156	Yes
36	BLACK EAGLE CASCADE COUNTY WATER SEWER Black Eagle	Black Eagle	Surface Water	4	1,233	Yes
37	FROMBERG TOWN OF Fromberg	Fromberg	Groundwater	4	500	Yes
38	HEART BUTTE WATER SYSTEM Browning	Browning	Groundwater	4	400	Yes
39	WILSALL WATER DISTRICT Wilsall	Wilsall	Surface Water	4	250	Yes
40	HIGH QUALITY H2O Missoula	Missoula	Groundwater	4	200	Yes
41	OPHEIM TOWN OF Opheim	Opheim	Surface Water	4	111	Yes
42	BIG BEND RANCH SUBDIVISION Great Falls	Great Falls	Groundwater	4	100	Yes
43	LAUREL MUNICIPAL WATER SYSTEM Laurel	Laurel	Surface Water	3	6,339	Yes
44	TOWN OF BROWNING Browning	Browning	Surface Water	3	4,671	Yes
45	TWO MEDICINE WATER - EAST GLACIER Browning	Browning	Surface Water	3	1,504	Yes
46	BOULDER CITY OF Boulder	Boulder	Groundwater	3	1,400	Yes
47	TEN MILE AND PLEASANT VALLEY WUA Helena	Helena	Groundwater	3	750	Yes
48	ST IGNATIUS TOWN OF St Ignatius	St Ignatius	Groundwater	3	700	Yes
49	WIBAUX TOWN OF Wibuax	Wibuax	Groundwater	3	550	Yes
50	SKYVIEW WATER AND SEWER UTILITY East Helena	East Helena	Groundwater	3	400	Yes
51	COOKE CITY WATER DISTRICT Cooke City	Cooke City	Groundwater	3	300	Yes
52	NASHUA TOWN OF Nashua	Nashua	Surface Water	3	300	Yes
53	ASHLAND COMMUNITY WATER SYSTEM Lame Deer	Lame Deer	Groundwater	3	265	Yes
54	WYOLA WATER SYSTEM Crow Agency	Crow Agency	Groundwater	3	261	Yes
55	GERALDINE TOWN OF Geraldine	Geraldine	Groundwater	3	260	Yes
56	GRANITE PARK WATER ASSOCIATION Billings	Billings	Groundwater	3	250	Yes
57	MNIHNAPA WATER SYSTEM Harlem	Harlem	Groundwater	3	220	Yes
58	BASIN COUNTY WATER AND SEWER DIST Basin	Basin	Groundwater	3	200	Yes
59	WEST YELLOWSTONE TOWN OF West Yellowstone	West Yellowstone	Groundwater	2	9,899	Yes
60	MALMSTROM AIR FORCE BASE Malmstrom Air Force Base	Malmstrom Air Force Base	Surface Water	2	8,850	Yes
61	LEWISTOWN CITY OF Lewistown	Lewistown	Groundwater	2	5,923	Yes
62	RONAN CITY OF Ronan	Ronan	Surface Water	2	2,483	Yes
63	EUREKA TOWN OF Eureka	Eureka	Surface Water	2	1,995	Yes
64	BIG TIMBER CITY OF Big Timber	Big Timber	Surface Water	2	1,650	Yes
65	FAIRVIEW TOWN OF Fairview	Fairview	Groundwater	2	1,000	Yes
66	DARBY TOWN OF Darby	Darby	Groundwater	2	850	Yes
67	JEFFERSON HILLS WUA Helena	Helena	Groundwater	2	780	Yes
68	BEDROCKBABB WATER SYSTEM Browning	Browning	Groundwater	2	645	Yes
69	HOMESTEAD ACRES COUNTY WATER AND SEWER Great Falls	Great Falls	Groundwater	2	500	Yes
70	ALBERTON TOWN OF Alberton	Alberton	Groundwater	2	495	Yes
71	BAXTER CREEK NO 2 HOA Belgrade	Belgrade	Groundwater	2	450	Yes
72	PRYOR WATER SYSTEM Crow Agency	Crow Agency	Groundwater	2	406	Yes
73	ASHLAND WATER AND SEWER DIST Ashland	Ashland	Groundwater	2	400	Yes
74	LOWER PIONEER MOUNTAIN WATER SYSTEM Big Sky	Big Sky	Groundwater	2	350	Yes
75	DUTTON TOWN OF Dutton	Dutton	Groundwater	2	338	Yes
76	SEVILLE WATER SYSTEM Browning	Browning	Surface Water	2	300	Yes
77	STARR SCHOOL WATER SYSTEM Browning	Browning	Groundwater	2	250	Yes
78	HINSDALE WATER DEPARTMENT Hinsdale	Hinsdale	Groundwater	2	250	Yes
79	RYAN DAM WATER SYSTEM Helena	Helena	Groundwater	2	230	Yes
80	HILLTOP TERRACE SUBDIVISION Kalispell	Kalispell	Groundwater	2	230	Yes
81	FLATHEAD COUNTY WATER DIST 101 Columbia Falls	Columbia Falls	Groundwater	2	210	Yes
82	GOODAN KEIL CO WATER DIST Missoula	Missoula	Groundwater	2	207	Yes
83	STILL RIVER ESTATES SUBDIVISION Billings	Billings	Groundwater	2	188	Yes
84	SAND COULEE WATER USERS DISTRICT Sand Coulee	Sand Coulee	Groundwater	2	180	Yes
85	ELK MEADOWS RANCHETTES Huson	Huson	Groundwater	2	175	Yes
86	PINEWOOD VILLAGE Libby	Libby	Groundwater	2	160	Yes
87	ARLEE Pablo	Pablo	Groundwater	2	124	Yes
88	DODSON TOWN OF Dodson	Dodson	Groundwater	2	120	Yes
89	BIRCH CREEK COLONY Valier	Valier	Groundwater	2	120	Yes
90	WETTINGTON WATER DISTRICT INC Kalispell	Kalispell	Groundwater	2	119	Yes
91	WOODSIDE PARK COUNTY WATER AND SEWER DIS Thoimpson Falls	Thoimpson Falls	Groundwater	2	115	Yes
92	WINDMILL TRAILER PARK WELL 1 Livingston	Livingston	Groundwater	2	110	Yes
93	SWEETGRASS WATER USERS ASSN Sweet Grass	Sweet Grass	Surface Water	2	100	Yes
94	GODFREY CANYON ESTATES Manhattan	Manhattan	Groundwater	2	100	Yes
95	CAMROSE COLONY Ledger	Ledger	Surface Water	2	95	Yes
96	BUTTE SILVERBOW WATER DEPT Butte	Butte	Surface Water	1	33,000	Yes
97	BELGRADE CITY OF Belgrade	Belgrade	Groundwater	1	10,460	Yes
98	POPLAR, CITY OF Poplar	Poplar	Surface Water	1	3,025	Yes
99	EAST HELENA CITY OF East Helena	East Helena	Groundwater	1	2,114	Yes
100	ROCKY BOY'S RURAL WATER Box Elder	Box Elder	Groundwater	1	2,000	Yes
101	THREE FORKS CITY OF Three Forks	Three Forks	Groundwater	1	1,900	Yes
102	BAKER CITY OF Baker	Baker	Groundwater	1	1,858	Yes
103	ROCKY BOY AGENCY WATER SYSTEM Box Elder	Box Elder	Groundwater	1	1,442	Yes
104	HARLOWTON CITY OF Harlowton	Harlowton	Groundwater	1	1,050	Yes
105	WESTVIEW MOBILE HOME PARK Missoula	Missoula	Groundwater	1	947	Yes
106	HAYS/WHITE COW CANYON WS Harlem	Harlem	Groundwater	1	840	Yes
107	FRAZER WATER SYSTEM Wolf Point	Wolf Point	Surface Water	1	452	Yes
108	ANDESITE RIDGE WATER SYSTEM Big Sky	Big Sky	Groundwater	1	450	Yes
109	STANFORD TOWN OF Stanford	Stanford	Groundwater	1	425	Yes
110	BUSHARD WATER COMPANY Black Eagle	Black Eagle	Surface Water	1	425	Yes
111	BAINVILLE TOWN OF Bainville	Bainville	Surface Water	1	350	Yes
112	ROBERTS WUA CARBON CO WATER AND SEWER Roberts	Roberts	Groundwater	1	300	Yes
113	ANACONDA CCC Anaconda	Anaconda	Surface Water	1	290	Yes
114	WINIFRED TOWN OF Winifred	Winifred	Groundwater	1	274	Yes
115	ORLAND ESTATES MOBILE H.P. Billings	Billings	Groundwater	1	244	Yes
116	HUNTLEY YELLOWSTONE CO WATER AND SEWER Huntley	Huntley	Groundwater	1	230	Yes
117	NEIHART TOWN OF Neihart	Neihart	Surface Water	1	229	Yes
118	TURTLE LAKE WATER SYSTEM Pablo	Pablo	Groundwater	1	225	Yes
119	HOLMBERG VILLAGE ESTATES Helena	Helena	Groundwater	1	225	Yes
120	DIXON, TOWN OF Pablo	Pablo	Groundwater	1	216	Yes
121	ELMO WATER SYSTEM Pablo	Pablo	Groundwater	1	210	Yes
122	STOCKETT WATER AND SEWER DIST Stockett	Stockett	Groundwater	1	210	Yes
123	GLACIER POINT HO AND WUA Helena	Helena	Groundwater	1	210	Yes
124	WILDERNESS PLATEAU WATER AND SEWER DIST Troy	Troy	Groundwater	1	208	Yes
125	BELFRY CARBON CO WATER AND SEWER DIST Belfry	Belfry	Groundwater	1	205	Yes
126	BAIR CLARK PROPERTIES, LLC Missoula	Missoula	Groundwater	1	180	Yes
127	CINNABAR THE Gardiner	Gardiner	Groundwater	1	175	Yes
128	SPRING MEADOWS COUNTY WATER DISTRICT Missoula	Missoula	Groundwater	1	162	Yes
129	CARTER CHOUTEAU CO WATER DIST Carter	Carter	Surface Water	1	150	Yes
130	NORTHWOODS WATER SYSTEM COOP INC Columbia Falls	Columbia Falls	Groundwater	1	135	Yes
131	SUNNY MEADOWS WATER AND SEWER DIST Missoula	Missoula	Groundwater	1	135	Yes
132	EMBARK AT FLATHEAD VALLEY Marion	Marion	Groundwater	1	130	Yes
133	HILDRETH SUBDIVISION NO 3 Dillon	Dillon	Groundwater	1	128	Yes
134	GOLDEN EAGLE WATER USERS ASSN Billings	Billings	Groundwater	1	125	Yes
135	KINGSBURY COLONY Valier	Valier	Groundwater	1	120	Yes
136	WHISPERING TREES MOBILE PARK Stevensville	Stevensville	Groundwater	1	100	Yes
137	PIEGAN BORDER STATION Helena	Helena	Surface Water	1	94	Yes
138	ROCKPORT COLONY Pendroy	Pendroy	Groundwater	1	92	Yes

Systems with No Violations (362)

362 water systems in Montana have zero recorded violations. Showing the 50 largest by population served.

BILLINGS CITY OF (114,000) MISSOULA WATER (68,200) BOZEMAN CITY OF (56,000) KALISPELL PUBLIC WORKS (25,000) CO WATER DIST OF BILLINGS HEIGHTS (12,000) WHITEFISH CITY OF (10,418) FLATHEAD COUNTY WATER AND SEWER (7,775) LIVINGSTON CITY OF (7,500) ANACONDA WATER DEPARTMENT (6,750) BIGFORK COUNTY WATER AND SEWER (6,100) LOCKWOOD WATER AND SEWER DISTRICT (5,900) HAMILTON CITY OF (5,585) POLSON CITY OF (5,300) SIDNEY CITY OF (5,000) GLENDIVE CITY OF (4,873) COLUMBIA FALLS CITY OF (4,450) NORTH STAR ZOOT WATER (4,323) DILLON CITY OF (4,300) RIVER ROCK COUNTY WATER AND SEWER DIST (4,200) BIG SKY COUNTY WATER AND SEWER DIST 363 (4,132) SHELBY CITY OF (3,970) HARDIN CITY OF (3,500) LOLO WATER AND SEWER DIST (3,315) GLASGOW CITY OF (3,253) CUT BANK CITY OF (3,105) DRY PRAIRIE RURAL WATER AUTHORITY (3,005) WOLF POINT CITY OF (3,000) DEER LODGE CITY OF (2,900) CONRAD WATER DEPT (2,500) BIG MOUNTAIN WATER COMPANY (2,435) FORSYTH CITY OF (2,260) RAE WATER AND SEWER DIST 313 (2,220) MONTANA STATE PRISON (2,100) TROY CITY OF (2,100) STEVENSVILLE TOWN OF (2,090) RED LODGE WATER DEPT (2,000) TOWNSEND CITY OF (2,000) EASTGATE VILLAGE SEWER AND WATER (2,000) FAIRMONT HOT SPRINGS RESORT (1,965) THOMPSON FALLS CITY OF (1,950) COLUMBUS TOWN OF (1,900) ROUNDUP WATER DEPARTMENT (1,900) MALTA CITY OF (1,800) MANHATTAN TOWN OF (1,800) SUN PRAIRIE VILLAGE COUNTY (1,800) ASSINIBOINE & SIOUX RURAL WATER SYSTEM (1,726) HILL COUNTY WATER DISTRICTS (1,720) PLAINS TOWN OF (1,700) PLENTYWOOD WATER DEPARTMENT (1,700) CHOTEAU CITY OF (1,691) +312 more

All Water Systems in Montana (809)

Page 5 of 17, ordered by population served.

System	Population Served	Violations
ST IGNATIUS (MISSION) SO.SIDE	356	0
MT MOONLIGHT BASIN	355	0
CHERRY VIEW	352	0
BAINVILLE TOWN OF	350	1
SADDLE MOUNTAIN CORP CLANCY	350	0
WATER SERVICE INC TROUT CREEK	350	0
SUN PRAIRIE WATER DISTRICT	350	0
HIDDEN LAKE YELLOWSTONE COUNTY W AND S D	350	0
FIRELIGHT MEADOWS LLC	350	0
LOWER PIONEER MOUNTAIN WATER SYSTEM	350	2
RIVERSIDE WATER AND SEWER DIST	344	0
MARTIN CITY COUNTY WATER DISTRICT	340	0
DUTTON TOWN OF	338	2
IRON HORSE HOMEOWNERS ASSOC	335	0
NOXON WATER DISTRICT	330	0
FOREST PARK WATER USERS ASSOCIATION	323	0
EMERALD VIEW PARK	320	0
MOUNTAIN ACRES MB HM PK	320	0
SHILOH ROAD DEVELOPMENT	315	0
SOUTHSIDE PUBLIC WATER SUPPLY	306	0
SEVILLE WATER SYSTEM	300	2
CLYDE PARK WATER DEPT	300	0
COOKE CITY WATER DISTRICT	300	3
NASHUA TOWN OF	300	3
ROBERTS WUA CARBON CO WATER AND SEWER	300	1
OILMONT COUNTY WATER DISTRICT	300	11
MOUNTAIN MEADOWS ESTATES LLP	300	0
KELLER SUBDIVISION NO 2 HOA	300	0
HILDRETH SUBDIVISION NO 2	300	0
MOBILE CITY HOME PARK NO 2	300	0
NCMRWA NORTH SHELBY	300	0
JETTE LAKE LANDOWNERS ASSOCIATION	295	0
NORTHERN PINES COMMUNITY HOA	295	0
KEVIN TOWN OF	290	0
ANACONDA CCC	290	1
HIGHWOOD COUNTY WATER AND SEWER DISTRICT	280	0
AP WILLIAMS	280	0
RIDGEWOOD TERRACE MHP	280	0
LIMA TOWN OF	279	0
ROCKY MOUNTAIN HI RV PARK	275	0
TRAPPER CREEK JOB CORPS	275	0
GREAT FALLS RV PARK	274	0
WINIFRED TOWN OF	274	1
RYEGATE TOWN OF	270	8
ALPINE PACIFIC UTILITIES	270	0
ASHLAND COMMUNITY WATER SYSTEM	265	3
HYSHAM TOWN OF	262	19
WYOLA WATER SYSTEM	261	3
GERALDINE TOWN OF	260	3
COUNTRY LAKE HOMES WHITEFISH	260	0

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Frequently Asked Questions

How many water systems are in Montana?

Montana has 809 community water systems tracked by the EPA, serving a combined population of 814,186 people.

How many water systems in Montana have health violations?

198 water systems in Montana have health-based violations, which include Maximum Contaminant Level (MCL) and Treatment Technique (TT) violations. These represent 24% of all systems in the state.

What is the total number of water violations in Montana?

Montana water systems have accumulated 1,430 total violations across all 809 community water systems.

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About This Data

Water system data is from the EPA Safe Drinking Water Information System (SDWIS). Health-based violations include Maximum Contaminant Level (MCL) and Treatment Technique (TT) violations that may pose a direct risk to public health. Only community water systems (CWS) are included.

Source: U.S. Environmental Protection Agency, SDWIS Federal Reporting Services U.S. Environmental Protection Agency, SDWIS Federal Reporting Services

Read our methodology - how this data is sourced, computed, and verified.

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