Montana Water Quality — 110 Cities Tested

Analysis

Montana water quality overview

Montana's drinking water quality is fair overall, with an average score of 65.2 out of 100 across 110 cities tested. The median score is 65.3, serving a total population of 754,610 residents. 40% 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 110 cities tested (19%). 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: 73 cities use groundwater while 37 draw from surface water such as rivers, lakes, and reservoirs.

Key Concerns

Issues to watch in Montana

21 cities

PFAS Detected

19% 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).

95 cities

Health Violations

36,868 total violations recorded, 109 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: 17 B: 34 C: 15 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

110 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	Somers	A-	89.7	765	25
8	Hot Springs	A-	89	600	45
9	Hungry Horse	A-	88.6	1K	29
10	Scobey	A-	88.1	1K	10
11	Bridger	A-	87.4	800	36
12	Bigfork	A-	87	7K	37
13	Circle	A-	86.9	644	20
14	Alberton	A-	86.6	613	71
15	Joliet	A-	85.5	600	89
16	Colstrip	A-	85.2	2K	56
17	Forsyth	A-	85.2	2K	177
18	Plains	B+	84.8	2K	126
19	Plentywood	B+	84.8	2K	2
20	Culbertson	B+	84.2	4K	34
21	Ennis	B+	83.9	2K	122
22	Belt	B+	83.8	745	49
23	Absarokee	B+	83.4	1K	136
24	Huntley	B+	83.2	705	75
25	Lakeside	B+	82.9	2K	72
26	Butte	B+	82.8	33K	89
27	Vaughn	B+	82.4	585	29
28	Seeley Lake	B+	82.1	2K	88
29	Fort Harrison	B+	82.1	1K	14
30	Big Timber	B+	81.8	2K	64
31	Boulder	B+	81.7	1K	87
32	Fort Benton	B+	81.2	2K	37
33	Thompson Falls	B+	80.6	2K	108
34	Troy	B+	80.5	2K	102
35	Fairview	B+	80.1	1K	155
36	Sunburst	B	79.9	673	96
37	Warm Springs	B	79.6	721	11
38	Townsend	B	79.5	2K	235
39	Pinesdale	B	79.5	800	202
40	Medicine Lake	B	79	600	47
41	Wolf Point	B	77.8	4K	110
42	Red Lodge	B	77.2	2K	196
43	Chinook	B	77	1K	31
44	St Ignatius	B	76.5	765	175
45	Valier	B	75.4	804	173
46	Black Eagle	B	75.2	1K	45
47	Poplar	B	75	5K	32
48	Choteau	B-	73.9	2K	157
49	Fairfield	B-	73.3	718	209
50	Box Elder	B-	72.9	4K	225
51	Stevensville	B-	70.9	2K	124
52	Roundup	C+	69.8	2K	15
53	Harlowton	C+	68.5	1K	144
54	Virginia City	C+	68.4	2K	48
55	Miles City	C+	67	10K	71
56	Laurel	C+	65.3	7K	151
57	Ballantine	C+	65.2	800	114
58	Worden	C+	65.2	800	114
59	Glasgow	C+	65	3K	112
60	Fromberg	C	63.6	500	84
61	Darby	C	60.2	1K	246
62	Sheridan	C-	58.6	632	82
63	Stanford	C-	57.8	505	379
64	Eureka	C-	56.8	3K	232
65	Ronan	C-	56.5	3K	175
66	Sand Coulee	C-	55.6	510	507
67	Anaconda	D+	53.9	9K	342
68	Hamilton	D+	53	6K	450
69	Lolo	D+	52	4K	644
70	Whitehall	D+	52	2K	230
71	Polson	D+	51.2	6K	380
72	White Sulphur Springs	D+	51	1K	419
73	East Helena	D+	50	3K	941
74	Manhattan	D+	50	2K	369
75	Baker	D+	50	2K	251
76	Ashland	D+	50	1K	286
77	Wibaux	D+	50	550	139
78	Lewistown	D	49	6K	485
79	Cut Bank	D	49	4K	453
80	Crow Agency	D	49	2K	621
81	Deer Lodge	D	47.5	5K	162
82	West Yellowstone	D	47.2	10K	581
83	Livingston	D	47.2	8K	722
84	Shelby	D	47.2	4K	462
85	Harlem	D	47	4K	811
86	Chester	D	47	1K	178
87	Glendive	D	46.2	7K	615
88	Columbus	D	46	2K	224
89	Malta	D	46	2K	294
90	Columbia Falls	D	45.5	6K	449
91	Conrad	D	45	3K	240
92	Belgrade	F	44.5	15K	471
93	Hardin	F	44	4K	222
94	Lame Deer	F	44	4K	250
95	Big Sky	F	43.5	5K	593
96	Bozeman	F	43.4	66K	1652
97	Pablo	F	43	4K	542
98	Missoula	F	42.6	77K	4300
99	Havre	F	42.2	10K	495
100	Whitefish	F	42	14K	733
101	Clancy	F	42	1K	417
102	Philipsburg	F	42	1K	79
103	Dillon	F	41.2	5K	670
104	Sidney	F	41.2	5K	262
105	Browning	F	41	8K	263
106	Kalispell	F	40.1	39K	2471
107	Libby	F	40	5K	370
108	Billings	F	39.6	139K	1938
109	Helena	F	39.1	38K	2303
110	Great Falls	F	34.5	65K	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 6 cities · avg 71 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 2 cities · avg 70 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 3 cities · avg 58.9 Musselshell 1 city · avg 69.8 Park 2 cities · avg 68.8 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 1 city · avg 65 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+ (65.2/100). 46% of cities scored an A or B, while 40% 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 110 cities tested positive for PFAS "forever chemicals" (19%). 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