Montana Water Quality — 115 Cities Tested

Analysis

Montana water quality overview

Montana's drinking water quality is fair overall, with an average score of 65.7 out of 100 across 115 cities tested. The median score is 68.3, serving a total population of 801,651 residents. 38% of cities scored a D or F, pointing to significant water quality challenges in parts of the state. PFAS "forever chemicals" were detected in 21 of 115 cities tested (18%). 2 cities exceed the 2024 EPA maximum contaminant levels. 1 city has lead levels exceeding the EPA action level of 15 ppb, often indicating aging infrastructure with lead service lines or lead solder. The state relies on a mix of water sources: 76 cities use groundwater while 39 draw from surface water such as rivers, lakes, and reservoirs.

Key Concerns

Issues to watch in Montana

21 cities

PFAS Detected

18% of tested cities have PFAS in their water supply.

1 cities

Lead Exceedances

Lead levels above the EPA action level of 15 ppb (90th percentile).

99 cities

Health Violations

37,407 total violations recorded, 113 with unresolved issues.

19 cities

Failing Systems

Received a grade of F, indicating serious water quality issues.

Contaminant Data

Explore contaminants in Montana

Lead in Montana → Ranked by 90th percentile level (ppb) PFAS in Montana → Ranked by compounds detected Copper in Montana → Ranked by 90th percentile level (mg/L)

More contaminants tested in Montana

HAA5 → Chromium-6 → Arsenic → Nitrate → Strontium → 1,4-Dioxane → Manganese → Vanadium → Chlorate → Molybdenum → Lithium → NDMA →

State context

19

Superfund sites in Montana

EPA National Priorities List

31.4%

of Montana residents on fluoridated water

CDC, 2020

59,106

lbs released to surface water

Top 10 TRI facilities, 2023

18.4%

of Montana domestic wells exceed EPA arsenic limit

USGS, 4,200 samples · 10 µg/L MCL

Domestic well chemistry

Private-well water in Montana

Based on USGS Powell Domestic-Well Database — 3,678 private wells sampled across Montana. These wells are not regulated by the EPA; if you draw your tap from a private well, the public-system grade above does not apply to you.

1.8 µg/L

Median arsenic in domestic wells

P90 22.8 µg/L · max 676.0 µg/L

58 µg/L

Median manganese in domestic wells

30.1% exceed 300 µg/L aesthetic limit

Industrial pollution

Top industrial water polluters in Montana

Industrial polluters nearby

The 10 facilities reporting the most pounds released to surface water in Montana, 2023.

Total reported releases to surface water: 59,106 lbs

Facility	Top chemical	To surface water (lbs/yr)
CHS INC. LAUREL REFINERY Petroleum · CHS INC LAUREL, MT59044	Nitrate compounds (water dissociable; reportable only when in aqueous solution)	46,755
PAR MONTANA BILLINGS REFINERY Petroleum · PAR PACIFIC HOLDINGS INC BILLINGS, MT59101	Ammonia	6,227
WESTERN SUGAR COOPERATIVE.130130 Food · WESTERN SUGAR COOPERATIVE BILLINGS, MT59101	Ammonia	5,957
PHILLIPS 66 CO BILLINGS REFINERY Petroleum · PHILLIPS 66 CO BILLINGS, MT59101	Phenol	165
JUPITER SULPHUR LLC Chemicals · TESSENDERLO KERLEY INC BILLINGS, MT59101	Ammonia	1

+ 1 more facility

Source: EPA Toxic Release Inventory (TRI) 2023

Test your own tap

Get your Montana water tested

City-level data shows the source and infrastructure picture — but lead and other home-plumbing issues only show up at your tap. Find a state-certified lab, see what to test for, and what it costs.

Grade Distribution

How Montana cities scored

A: 19 B: 35 C: 17 D: 25 F: 19

Best Cities

Worst Cities

City Map

Water quality across Montana

Each dot is a city, colored by its water quality grade. Size reflects population served. Click any city to view its full water report.

All Cities

115 cities in Montana

Full rankings →

#	City	Grade	Score	Population	Violations
1	Cascade	A	94.3	650	8
2	Superior	A	93.2	1K	9
3	Three Forks	A	92.3	2K	74
4	West Glacier	A	91.1	2K	28
5	Gardiner	A	90.4	700	55
6	Big Sandy	A	90.4	608	28
7	Santa Rita	A-	89.9	628	27
8	Somers	A-	89.7	1K	25
9	Hot Springs	A-	89	600	45
10	Hungry Horse	A-	88.6	1K	29
11	Scobey	A-	88.1	1K	10
12	Bridger	A-	87.4	800	36
13	Bigfork	A-	87	7K	37
14	Circle	A-	86.9	644	20
15	Alberton	A-	86.6	738	71
16	Sun River	A-	86.2	630	53
17	Joliet	A-	85.5	600	89
18	Colstrip	A-	85.2	2K	56
19	Forsyth	A-	85.2	2K	177
20	Plains	B+	84.8	2K	126
21	Plentywood	B+	84.8	2K	2
22	Culbertson	B+	84.2	4K	34
23	Ennis	B+	83.9	2K	122
24	Belt	B+	83.8	745	49
25	Absarokee	B+	83.4	1K	136
26	Huntley	B+	83.2	705	75
27	Lakeside	B+	82.9	2K	72
28	Butte	B+	82.8	33K	89
29	Vaughn	B+	82.4	665	29
30	Seeley Lake	B+	82.1	2K	88
31	Fort Harrison	B+	82.1	1K	14
32	Big Timber	B+	81.8	2K	64
33	Boulder	B+	81.7	1K	87
34	Fort Benton	B+	81.2	2K	37
35	Thompson Falls	B+	80.6	2K	108
36	Troy	B+	80.5	3K	102
37	Fairview	B+	80.1	1K	155
38	Sunburst	B	79.9	748	96
39	Warm Springs	B	79.6	721	11
40	Townsend	B	79.5	2K	235
41	Pinesdale	B	79.5	800	202
42	Medicine Lake	B	79	600	47
43	Wolf Point	B	77.8	4K	110
44	Red Lodge	B	77.2	2K	196
45	Chinook	B	77	1K	31
46	St Ignatius	B	76.5	765	175
47	Valier	B	75.4	804	173
48	Black Eagle	B	75.2	2K	45
49	Poplar	B	75	5K	32
50	Fort Peck	B-	74.1	903	61
51	Choteau	B-	73.9	2K	157
52	Fairfield	B-	73.3	1K	209
53	Box Elder	B-	72.9	4K	225
54	Stevensville	B-	70.9	2K	124
55	Roundup	C+	69.8	2K	15
56	Harlowton	C+	68.5	2K	144
57	Virginia City	C+	68.4	2K	48
58	Corwin Springs	C+	68.3	700	95
59	Miles City	C+	67	10K	71
60	Frenchtown	C+	66.5	2K	303
61	Laurel	C+	65.3	7K	151
62	Ballantine	C+	65.2	800	114
63	Ballantine	C+	65.2	800	114
64	Glasgow	C+	65	3K	112
65	Fromberg	C	63.6	500	84
66	Darby	C	60.2	1K	246
67	Sheridan	C-	58.6	632	82
68	Stanford	C-	57.8	505	379
69	Eureka	C-	56.8	3K	232
70	Ronan	C-	56.5	3K	175
71	Sand Coulee	C-	55.6	590	507
72	Anaconda	D+	53.9	9K	342
73	Hamilton	D+	53	7K	450
74	Lolo	D+	52	4K	644
75	Whitehall	D+	52	2K	230
76	Polson	D+	51.2	6K	380
77	White Sulphur Springs	D+	51	1K	419
78	East Helena	D+	50	3K	941
79	Manhattan	D+	50	2K	369
80	Baker	D+	50	2K	251
81	Ashland	D+	50	1K	286
82	Wibaux	D+	50	550	139
83	Lewistown	D	49	6K	485
84	Cut Bank	D	49	4K	453
85	Crow Agency	D	49	2K	621
86	Deer Lodge	D	47.5	5K	162
87	West Yellowstone	D	47.2	10K	581
88	Livingston	D	47.2	8K	722
89	Shelby	D	47.2	5K	462
90	Harlem	D	47	4K	811
91	Chester	D	47	2K	178
92	Glendive	D	46.2	7K	615
93	Columbus	D	46	2K	224
94	Malta	D	46	2K	294
95	Columbia Falls	D	45.5	6K	449
96	Conrad	D	45	4K	240
97	Belgrade	F	44.5	16K	471
98	Hardin	F	44	4K	222
99	Lame Deer	F	44	4K	250
100	Big Sky	F	43.5	6K	593
101	Bozeman	F	43.4	69K	1652
102	Pablo	F	43	4K	542
103	Missoula	F	42.6	78K	4300
104	Havre	F	42.2	12K	495
105	Whitefish	F	42	16K	733
106	Clancy	F	42	1K	417
107	Philipsburg	F	42	1K	79
108	Sidney	F	41.2	5K	262
109	Dillon	F	41.2	5K	670
110	Browning	F	41	8K	263
111	Kalispell	F	40.1	42K	2471
112	Libby	F	40	5K	370
113	Billings	F	39.6	143K	1938
114	Helena	F	39.1	44K	2303
115	Great Falls	F	34.5	76K	1361

Counties

Browse Montana counties

Beaverhead 1 city · avg 41.2 Big Horn 1 city · avg 44 Blaine 2 cities · avg 62 Broadwater 1 city · avg 79.5 Carbon 4 cities · avg 78.4 Cascade 7 cities · avg 73.1 Chouteau 2 cities · avg 85.8 Custer 1 city · avg 67 Daniels 1 city · avg 88.1 Dawson 1 city · avg 46.2 Deer Lodge 2 cities · avg 66.8 Fallon 1 city · avg 50 Fergus 1 city · avg 49 Flathead 7 cities · avg 68 Gallatin 5 cities · avg 55.5 Glacier 3 cities · avg 76.7 Granite 1 city · avg 42 Hill 1 city · avg 42.2 Jefferson 3 cities · avg 58.6 Judith Basin 1 city · avg 57.8 Lake 4 cities · avg 56.8 Lewis And Clark 3 cities · avg 57.1 Liberty 1 city · avg 47 Lincoln 3 cities · avg 59.1 Madison 4 cities · avg 63.6 Mccone 1 city · avg 86.9 Meagher 1 city · avg 51 Mineral 2 cities · avg 89.9 Missoula 4 cities · avg 60.8 Musselshell 1 city · avg 69.8 Park 3 cities · avg 68.6 Phillips 1 city · avg 46 Pondera 2 cities · avg 60.2 Powell 1 city · avg 47.5 Ravalli 4 cities · avg 65.9 Richland 2 cities · avg 60.6 Roosevelt 1 city · avg 84.2 Rosebud 3 cities · avg 73.5 Sanders 3 cities · avg 84.8 Sheridan 2 cities · avg 81.9 Silver Bow 1 city · avg 82.8 Stillwater 2 cities · avg 64.7 Sweet Grass 1 city · avg 81.8 Teton 2 cities · avg 73.6 Toole 2 cities · avg 63.6 Valley 2 cities · avg 69.5 Wheatland 1 city · avg 68.5 Wibaux 1 city · avg 50 Yellowstone 5 cities · avg 63.7

ZIP Codes

Browse Montana by ZIP code

Look up water quality by ZIP code to find the systems serving your area.

View all Montana ZIP codes →

FAQ

Frequently asked questions about Montana's water

Is Montana's tap water safe to drink?

Montana's water quality varies by city. The statewide average grade is C+ (65.7/100). 47% of cities scored an A or B, while 38% received a D or F. Check your specific city for detailed results.

Which Montana cities have the best water quality?

The top-rated cities are Cascade (A), Superior (A), Three Forks (A). These cities scored highest based on violation history, lead levels, PFAS contamination, and regulatory compliance.

Which Montana cities have the worst water quality?

The lowest-rated cities are Great Falls (F), Helena (F), Billings (F). We recommend residents in these areas consider water filtration and review their city's specific contaminant data.

How many Montana cities have PFAS in their water?

21 out of 115 cities tested positive for PFAS "forever chemicals" (18%). 2 cities exceed the 2024 EPA maximum contaminant levels. Reverse osmosis or activated carbon filters can help reduce PFAS exposure.

Do any Montana cities have dangerous lead levels?

1 city exceeds the EPA lead action level of 15 ppb. Lead contamination typically comes from aging pipes and lead service lines rather than the water source itself. An NSF 53-certified filter can effectively remove lead from tap water.

Montana Water Quality Report