Montana Water Systems

Compiled by PlainEnviro · August 25, 2026

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

Water Systems

818

Health-Based Violation Records

1,604

Health Violations

201 systems

Population Served

816,767

Montana community water systems are regulated by the EPA Safe Drinking Water Information System (SDWIS) under the Safe Drinking Water Act; each utility files compliance results with the state's primacy agency and, for federally listed contaminants, with the U.S. Environmental Protection Agency directly. PlainEnviro's health-based SDWIS extract above counts health-based exceedances only -- monitoring and reporting violations are not present in these figures.

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? (137)

#	System Name	City	Source	Violations	Pop. Served	Health
1	FORT BELKNAP AGENCY WATER SYSTEM Harlem	Harlem	Surface Water	211	2,600	Yes
2	DENTON TOWN OF Denton	Denton	Surface Water	162	255	Yes
3	WHITEHALL TOWN OF Whitehall	Whitehall	Groundwater	91	1,500	Yes
4	HARLEM CITY OF Harlem	Harlem	Surface Water	71	820	Yes
5	ST LABRE INDIAN SCHOOL Ashland	Ashland	Groundwater	60	650	Yes
6	CROW AGENCY WATER SYSTEM Crow Agency	Crow Agency	Surface Water	53	2,057	Yes
7	PHILIPSBURG TOWN OF Philipsburg	Philipsburg	Surface Water	30	1,360	Yes
8	NCMRWA TIBER SERVICE AREA Helena	Helena	Surface Water	29	200	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	LIBBY CITY OF Libby	Libby	Surface Water	13	4,892	Yes
16	HELENA WATER SYSTEM Helena	Helena	Surface Water	12	32,091	Yes
17	CHINOOK CITY OF Chinook	Chinook	Surface Water	11	1,300	Yes
18	OILMONT COUNTY WATER DISTRICT Sunburst	Sunburst	Groundwater	11	300	Yes
19	BIRNEY VILLAGE Lame Deer	Lame Deer	Groundwater	11	96	Yes
20	HAVRE CITY OF Havre	Havre	Surface Water	10	9,921	Yes
21	MILES CITY CITY OF Miles City	Miles City	Surface Water	10	9,565	Yes
22	VIRGINIA CITY WATER DEPT Virginia City	Virginia City	Groundwater	9	1,500	Yes
23	WORDEN BALLANTINE YELLOWSTONE Ballantine	Ballantine	Surface Water	9	800	Yes
24	RYEGATE TOWN OF Ryegate	Ryegate	Groundwater	8	270	Yes
25	PABLO LAKE COUNTY WATER AND SEWER DIST Pablo	Pablo	Groundwater	7	2,175	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	FROMBERG TOWN OF Fromberg	Fromberg	Groundwater	6	498	Yes
32	WILSALL WATER DISTRICT Wilsall	Wilsall	Surface Water	6	250	Yes
33	MT ELLIS ACADEMY Bozeman	Bozeman	Groundwater	6	106	Yes
34	GREAT FALLS CITY OF Great Falls	Great Falls	Surface Water	5	60,000	Yes
35	TWO MEDICINE WATER - EAST GLACIER Browning	Browning	Surface Water	5	1,504	Yes
36	PINESDALE TOWN OF Pinesdale	Pinesdale	Surface Water	5	800	Yes
37	BUSBY COMMUNITY WATER SYSTEM Lame Deer	Lame Deer	Groundwater	5	535	Yes
38	WYOLA WATER SYSTEM Crow Agency	Crow Agency	Groundwater	5	281	Yes
39	BLACK EAGLE CASCADE COUNTY WATER SEWER Black Eagle	Black Eagle	Surface Water	4	1,233	Yes
40	HEART BUTTE WATER SYSTEM Browning	Browning	Groundwater	4	400	Yes
41	GRANITE PARK WATER ASSOCIATION Billings	Billings	Groundwater	4	250	Yes
42	HIGH QUALITY H2O Missoula	Missoula	Groundwater	4	200	Yes
43	OPHEIM TOWN OF Opheim	Opheim	Surface Water	4	111	Yes
44	BIG BEND RANCH SUBDIVISION Great Falls	Great Falls	Groundwater	4	100	Yes
45	LAUREL MUNICIPAL WATER SYSTEM Laurel	Laurel	Surface Water	3	6,339	Yes
46	TOWN OF BROWNING Browning	Browning	Surface Water	3	4,671	Yes
47	BOULDER CITY OF Boulder	Boulder	Groundwater	3	1,400	Yes
48	TEN MILE AND PLEASANT VALLEY WUA Helena	Helena	Groundwater	3	750	Yes
49	ST IGNATIUS TOWN OF St Ignatius	St Ignatius	Groundwater	3	700	Yes
50	WIBAUX TOWN OF Wibuax	Wibuax	Groundwater	3	550	Yes
51	BAXTER CREEK NO 2 HOA Belgrade	Belgrade	Groundwater	3	450	Yes
52	SKYVIEW WATER AND SEWER UTILITY East Helena	East Helena	Groundwater	3	400	Yes
53	COOKE CITY WATER DISTRICT Cooke City	Cooke City	Groundwater	3	300	Yes
54	NASHUA TOWN OF Nashua	Nashua	Surface Water	3	300	Yes
55	GERALDINE TOWN OF Geraldine	Geraldine	Groundwater	3	260	Yes
56	STARR SCHOOL WATER SYSTEM Browning	Browning	Groundwater	3	250	Yes
57	MNIHNAPA WATER SYSTEM Harlem	Harlem	Groundwater	3	220	Yes
58	ASHLAND COMMUNITY WATER SYSTEM Lame Deer	Lame Deer	Groundwater	3	210	Yes
59	BASIN COUNTY WATER AND SEWER DIST Basin	Basin	Groundwater	3	200	Yes
60	DODSON TOWN OF Dodson	Dodson	Groundwater	3	120	Yes
61	SWEETGRASS WATER USERS ASSN Sweet Grass	Sweet Grass	Surface Water	3	100	Yes
62	WEST YELLOWSTONE TOWN OF West Yellowstone	West Yellowstone	Groundwater	2	9,899	Yes
63	MALMSTROM AIR FORCE BASE Malmstrom Air Force Base	Malmstrom Air Force Base	Surface Water	2	8,850	Yes
64	LEWISTOWN CITY OF Lewistown	Lewistown	Groundwater	2	5,923	Yes
65	RONAN CITY OF Ronan	Ronan	Surface Water	2	2,483	Yes
66	EUREKA TOWN OF Eureka	Eureka	Surface Water	2	1,995	Yes
67	BIG TIMBER CITY OF Big Timber	Big Timber	Surface Water	2	1,650	Yes
68	FAIRVIEW TOWN OF Fairview	Fairview	Groundwater	2	1,000	Yes
69	DARBY TOWN OF Darby	Darby	Groundwater	2	850	Yes
70	JEFFERSON HILLS WUA Helena	Helena	Groundwater	2	780	Yes
71	BEDROCKBABB WATER SYSTEM Browning	Browning	Groundwater	2	645	Yes
72	HOMESTEAD ACRES COUNTY WATER AND SEWER Great Falls	Great Falls	Groundwater	2	500	Yes
73	ALBERTON TOWN OF Alberton	Alberton	Groundwater	2	495	Yes
74	BUSHARD WATER COMPANY Black Eagle	Black Eagle	Surface Water	2	425	Yes
75	PRYOR WATER SYSTEM Crow Agency	Crow Agency	Groundwater	2	406	Yes
76	ASHLAND WATER AND SEWER DIST Ashland	Ashland	Groundwater	2	400	Yes
77	LOWER PIONEER MOUNTAIN WATER SYSTEM Big Sky	Big Sky	Groundwater	2	350	Yes
78	DUTTON TOWN OF Dutton	Dutton	Groundwater	2	338	Yes
79	SEVILLE WATER SYSTEM Browning	Browning	Surface Water	2	300	Yes
80	HINSDALE WATER DEPARTMENT Hinsdale	Hinsdale	Groundwater	2	250	Yes
81	RYAN DAM WATER SYSTEM Helena	Helena	Groundwater	2	230	Yes
82	HILLTOP TERRACE SUBDIVISION Kalispell	Kalispell	Groundwater	2	230	Yes
83	HOLMBERG VILLAGE ESTATES Helena	Helena	Groundwater	2	225	Yes
84	ELMO WATER SYSTEM Pablo	Pablo	Groundwater	2	220	Yes
85	FLATHEAD COUNTY WATER DIST 101 Columbia Falls	Columbia Falls	Groundwater	2	210	Yes
86	GOODAN KEIL CO WATER DIST Missoula	Missoula	Groundwater	2	207	Yes
87	DIXON, TOWN OF Pablo	Pablo	Groundwater	2	200	Yes
88	STILL RIVER ESTATES SUBDIVISION Billings	Billings	Groundwater	2	188	Yes
89	SAND COULEE WATER USERS DISTRICT Sand Coulee	Sand Coulee	Groundwater	2	180	Yes
90	ELK MEADOWS RANCHETTES Huson	Huson	Groundwater	2	175	Yes
91	PINEWOOD VILLAGE Libby	Libby	Groundwater	2	160	Yes
92	CARTER CHOUTEAU CO WATER DIST Carter	Carter	Surface Water	2	150	Yes
93	ARLEE Pablo	Pablo	Groundwater	2	124	Yes
94	BIRCH CREEK COLONY Valier	Valier	Groundwater	2	120	Yes
95	WETTINGTON WATER DISTRICT INC Kalispell	Kalispell	Groundwater	2	119	Yes
96	BIG ARM WATER SYSTEM Pablo	Pablo	Groundwater	2	116	Yes
97	WOODSIDE PARK COUNTY WATER AND SEWER DIS Thoimpson Falls	Thoimpson Falls	Groundwater	2	115	Yes
98	WINDMILL TRAILER PARK WELL 1 Livingston	Livingston	Groundwater	2	110	Yes
99	GUERNSEY LAKE MOBILE HOME COMMUNITY Stevensville	Stevensville	Groundwater	2	100	Yes
100	GODFREY CANYON ESTATES Manhattan	Manhattan	Groundwater	2	100	Yes
101	CAMROSE COLONY Ledger	Ledger	Surface Water	2	95	Yes
102	BUTTE SILVERBOW WATER DEPT Butte	Butte	Surface Water	1	33,000	Yes
103	BELGRADE CITY OF Belgrade	Belgrade	Groundwater	1	10,460	Yes
104	POPLAR, CITY OF Poplar	Poplar	Surface Water	1	3,025	Yes
105	EAST HELENA CITY OF East Helena	East Helena	Groundwater	1	2,114	Yes
106	ROCKY BOY'S RURAL WATER Box Elder	Box Elder	Groundwater	1	2,000	Yes
107	THREE FORKS CITY OF Three Forks	Three Forks	Groundwater	1	1,900	Yes
108	BAKER CITY OF Baker	Baker	Groundwater	1	1,858	Yes
109	ROCKY BOY AGENCY WATER SYSTEM Box Elder	Box Elder	Groundwater	1	1,442	Yes
110	HARLOWTON CITY OF Harlowton	Harlowton	Groundwater	1	1,050	Yes
111	WESTVIEW MOBILE HOME PARK Missoula	Missoula	Groundwater	1	947	Yes
112	HAYS/WHITE COW CANYON WS Harlem	Harlem	Groundwater	1	840	Yes
113	FRAZER WATER SYSTEM Wolf Point	Wolf Point	Surface Water	1	452	Yes
114	ANDESITE RIDGE WATER SYSTEM Big Sky	Big Sky	Groundwater	1	450	Yes
115	STANFORD TOWN OF Stanford	Stanford	Groundwater	1	425	Yes
116	BAINVILLE TOWN OF Bainville	Bainville	Surface Water	1	350	Yes
117	ROBERTS WUA CARBON CO WATER AND SEWER Roberts	Roberts	Groundwater	1	300	Yes
118	ANACONDA CCC Anaconda	Anaconda	Surface Water	1	290	Yes
119	WINIFRED TOWN OF Winifred	Winifred	Groundwater	1	274	Yes
120	ORLAND ESTATES MOBILE H.P. Billings	Billings	Groundwater	1	244	Yes
121	HUNTLEY YELLOWSTONE CO WATER AND SEWER Huntley	Huntley	Groundwater	1	230	Yes
122	NEIHART TOWN OF Neihart	Neihart	Surface Water	1	229	Yes
123	TURTLE LAKE WATER SYSTEM Pablo	Pablo	Groundwater	1	225	Yes
124	STOCKETT WATER AND SEWER DIST Stockett	Stockett	Groundwater	1	210	Yes
125	GLACIER POINT HO AND WUA Helena	Helena	Groundwater	1	210	Yes
126	WILDERNESS PLATEAU WATER AND SEWER DIST Troy	Troy	Groundwater	1	208	Yes
127	BELFRY CARBON CO WATER AND SEWER DIST Belfry	Belfry	Groundwater	1	205	Yes
128	BAIR CLARK PROPERTIES, LLC Missoula	Missoula	Groundwater	1	180	Yes
129	CINNABAR THE Gardiner	Gardiner	Groundwater	1	175	Yes
130	SPRING MEADOWS COUNTY WATER DISTRICT Missoula	Missoula	Groundwater	1	162	Yes
131	NORTHWOODS WATER SYSTEM COOP INC Columbia Falls	Columbia Falls	Groundwater	1	135	Yes
132	SUNNY MEADOWS WATER AND SEWER DIST Missoula	Missoula	Groundwater	1	135	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

Systems with No Violations (363)

363 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) BILLINGS HEIGHTS CO WATER DIST OF (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 (5,660) 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) RAE WATER AND SEWER DIST 313 (2,325) FORSYTH CITY OF (2,260) 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) +313 more

All Water Systems in Montana (818)

Page 4 of 17, ordered by population served.

System	Population Served	Violations
HOMESTEAD ACRES COUNTY WATER AND SEWER	500	2
HIGHLAND PARK UTILITIES ASSN	500	0
HEADQUARTERS APGAR	500	0
COVERED WAGON MB HM PARK	500	0
FROMBERG TOWN OF	498	6
ALBERTON TOWN OF	495	2
COUNTRY ESTATES WATER SUPPLY	490	0
TREASURE STATE ACRES WUA	483	0
LODGE GRASS TOWN OF	480	0
CUSTER CO WATER AND SEWER DIST	480	0
CUT BANK NORTH WATER DISTRICT	478	0
FLATHEAD CO WATER DISTRICT NO 8	475	0
PRYOR CREEK WATER ASSN	475	0
TRI COUNTY WATER DISTRICT	470	0
SUNBURST TOWN OF	459	0
INDIAN SPRINGS RANCH SUB	455	0
FRAZER WATER SYSTEM	452	1
VALIER TOWN OF	452	0
BROADUS TOWN OF	450	0
CONSOLIDATED CHARLO LAKE CO W AND S DIST	450	0
CORAM COUNTY WATER AND SEWER DISTRICT	450	0
FROID TOWN OF	450	0
GREENACRES COUNTY WATER AND SEWER DIST	450	0
BAXTER CREEK NO 2 HOA	450	3
NORTH VALLEY COUNTY WATER AND SEWER DIST	450	0
ANDESITE RIDGE WATER SYSTEM	450	1
FORT SMITH WATER AND SEWER DISTRICT	450	0
WILDERNESS CLUB THE	440	0
STANFORD TOWN OF	425	1
BUSHARD WATER COMPANY	425	2
TWIN BRIDGES TOWN OF	424	0
MEADOW MANOR	410	0
PRYOR WATER SYSTEM	406	2
LA CASA GRANDE WATER AND SEWER DISTRICT	404	0
HEART BUTTE WATER SYSTEM	400	4
EAGLEMAN COMMUNITY WATER	400	0
EKALAKA TOWN OF	400	0
ROUND BUTTE WATER COMPANY	400	0
ASHLAND WATER AND SEWER DIST	400	2
WYLIE CREEK ESTATES SUBDIVISION	400	0
SKYVIEW WATER AND SEWER UTILITY	400	3
GOLDEN ESTATES HOMEOWNERS ASSOCIATION	400	0
HIGHWOOD MOBILE HOME PARK	400	0
FOREST ACRES TR PK WHITEFISH	390	0
GRANT CREEK WATER USERS ASSOCIATION INC	380	0
SUNDANCE SUBDIVISION	378	0
STONE CREEK SUBDIVISION	378	0
BROCKTON, TOWN OF	375	0
JETTE MEADOWS LAKE CO W AND S DIST	375	0
DRY REDWATER REGIONAL WATER AUTHORITY	365	0

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Frequently Asked Questions

How many water systems are in Montana?

Montana has 818 community water systems tracked by the EPA, serving a combined population of 816,767 people.

How many water systems in Montana have health violations?

201 water systems in Montana have health-based violations, which include Maximum Contaminant Level (MCL) and Treatment Technique (TT) violations. These represent 25% of all systems in the state.

How many health-based violation records are in this extract for Montana?

PlainEnviro's health-based EPA SDWIS extract contains 1,604 records joined to 818 active community water systems in Montana. Monitoring and reporting records are not included.

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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

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

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