Data: EPA SDWIS, NWS, State plumbing boards, Rewiring America Last verified: 2026-06-03

Recent compliance reports place Montana below the national average for public water safety.

Score Distribution

How Montana's 405 ZIP codes are distributed across safety grades.

Top 10 Safest ZIP Codes in Montana

Highest Home Safety Scores in the state.

10 Lowest-Scoring ZIP Codes in Montana

County Rankings

Water quality breakdown by county. 55 counties with data in Montana.

Most Common Contaminants in Montana

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Overview

We track water quality, weather alerts, plumbing regulations, and energy rebates for 405 ZIP codes across Montana, covering 442 community water systems that serve approximately 640,439 people.

212 of 405 ZIP codes (52%) have recorded EPA violations. 431 health-based violations have been documented.

Plumbing Regulations

Montana follows the International Plumbing Code (2021 edition).

• Plumbing code: IPC (2021)
• Homeowner DIY: Allowed with permit
• Water heater permit: Required
• Annual backflow test: Required

Full Montana regulations →

Areas with Most Violations

Areas with No Violations

Home Safety Score

Average Home Safety Score for Montana: C (55/100)

Lead & Copper

• Average lead level (90th percentile): 0.0034 mg/L (EPA action level: 0.015 mg/L)
• 3 ZIP codes exceed the EPA lead action level

Radon Risk

• High risk (Zone 1): 355 ZIP codes (88%)
• Moderate risk (Zone 2): 50 ZIP codes
• Low risk (Zone 3): 0 ZIP codes

ZIP Code Reports for Montana

Largest Communities

Lowest Safety Scores

Highest Safety Scores

All 405 ZIP Codes in Montana

• 59001 (Absarokee) [C] — 2 violations
• 59002 (Acton) [D]
• 59820 (Alberton) [C] — 4 violations ⚠
• 59710 (Alder) [C] — 6 violations
• 59311 (Alzada) [D]
• 59711 (Anaconda) [C] — 8 violations
• 59312 (Angela) [D]
• 59211 (Antelope) [C] — 6 violations
• 59821 (Arlee) [D]
• 59003 (Ashland) [F] — 31 violations ⚠
• 59004 (Ashland) [F] — 31 violations ⚠
• 59410 (Augusta) [C] — 2 violations
• 59713 (Avon) [D]
• 59411 (Babb) [C] — 5 violations
• 59212 (Bainville) [C] — 3 violations
• 59313 (Baker) [C] — 10 violations
• 59006 (Ballantine) [D]
• 59631 (Basin) [C] — 9 violations ⚠
• 59007 (Bearcreek) [D]
• 59008 (Belfry) [B]
• 59714 (Belgrade) [C] — 21 violations
• 59412 (Belt) [C] — 3 violations
• 59314 (Biddle) [D]
• 59910 (Big Arm) [D]
• 59520 (Big Sandy) [C] — 2 violations
• 59716 (Big Sky) [B] — 1 violation
• 59011 (Big Timber) [B]
• 59911 (Bigfork) [C] — 1 violation
• 59010 (Bighorn) [D]
• 59101 (Billings) [C] — 34 violations ⚠
• 59102 (Billings) [B] — 34 violations ⚠
• 59103 (Billings) [B] — 34 violations ⚠
• 59104 (Billings) [B] — 34 violations ⚠
• 59105 (Billings) [B] — 34 violations ⚠
• 59106 (Billings) [B] — 34 violations ⚠
• 59107 (Billings) [B] — 34 violations ⚠
• 59108 (Billings) [B] — 34 violations ⚠
• 59111 (Billings) [B] — 34 violations ⚠
• 59112 (Billings) [B] — 34 violations ⚠
• 59114 (Billings) [B] — 34 violations ⚠
• 59115 (Billings) [B] — 34 violations ⚠
• 59116 (Billings) [B] — 34 violations ⚠
• 59117 (Billings) [B] — 34 violations ⚠
• 59012 (Birney) [D]
• 59414 (Black Eagle) [C] — 7 violations ⚠
• 59315 (Bloomfield) [D]
• 59823 (Bonner) [B]
• 59632 (Boulder) [D] — 2 violations ⚠
• 59521 (Box Elder) [D]
• 59013 (Boyd) [D]
• 59316 (Boyes) [D]
• 59715 (Bozeman) [C] — 3 violations
• 59717 (Bozeman) [C] — 3 violations
• 59718 (Bozeman) [C] — 3 violations
• 59719 (Bozeman) [C] — 3 violations
• 59771 (Bozeman) [C] — 3 violations
• 59772 (Bozeman) [C] — 3 violations
• 59773 (Bozeman) [C] — 3 violations
• 59416 (Brady) [C] — 9 violations ⚠
• 59014 (Bridger) [C] — 2 violations
• 59317 (Broadus) [C] — 3 violations
• 59015 (Broadview) [C] — 3 violations
• 59213 (Brockton) [D]
• 59214 (Brockway) [D]
• 59417 (Browning) [D]
• 59318 (Brusett) [D]
• 59418 (Buffalo) [D]
• 59016 (Busby) [D]
• 59701 (Butte) [C] — 8 violations
• 59702 (Butte) [C] — 8 violations
• 59703 (Butte) [C] — 8 violations
• 59707 (Butte) [C] — 8 violations
• 59750 (Butte) [C] — 8 violations
• 59419 (Bynum) [C] — 6 violations
• 59720 (Cameron) [D]
• 59633 (Canyon Creek) [D]
• 59319 (Capitol) [D]
• 59721 (Cardwell) [D]
• 59420 (Carter) [D] — 8 violations
• 59421 (Cascade) [B]
• 59824 (Charlo) [D] — 3 violations
• 59522 (Chester) [C] — 15 violations ⚠
• 59523 (Chinook) [D] — 6 violations ⚠
• 59422 (Choteau) [C] — 3 violations
• 59215 (Circle) [C] — 5 violations
• 59634 (Clancy) [D] — 11 violations
• 59825 (Clinton) [D]
• 59018 (Clyde Park) [C] — 4 violations
• 59424 (Coffee Creek) [D]
• 59322 (Cohagen) [D]
• 59323 (Colstrip) [C] — 5 violations ⚠
• 59912 (Columbia Falls) [C] — 2 violations
• 59019 (Columbus) [C] — 10 violations
• 59826 (Condon) [D]
• 59827 (Conner) [D]
• 59425 (Conrad) [C] — 8 violations ⚠
• 59020 (Cooke City) [C] — 6 violations
• 59913 (Coram) [C] — 3 violations
• 59828 (Corvallis) [B]
• 59217 (Crane) [D]
• 59022 (Crow Agency) [D]
• 59218 (Culbertson) [C] — 2 violations
• 59024 (Custer) [C]
• 59427 (Cut Bank) [C] — 2 violations
• 59219 (Dagmar) [D]
• 59829 (Darby) [C] — 9 violations ⚠
• 59914 (Dayton) [D]
• 59830 (De Borgia) [D]
• 59025 (Decker) [D]
• 59722 (Deer Lodge) [C] — 8 violations
• 59724 (Dell) [D]
• 59430 (Denton) [D] — 61 violations ⚠
• 59725 (Dillon) [C] — 11 violations
• 59727 (Divide) [D]
• 59831 (Dixon) [D]
• 59524 (Dodson) [C] — 22 violations ⚠
• 59832 (Drummond) [D]
• 59432 (Dupuyer) [D]
• 59433 (Dutton) [C] — 7 violations ⚠
• 59434 (East Glacier Park) [D]
• 59635 (East Helena) [C] — 6 violations ⚠
• 59026 (Edgar) [D]
• 59324 (Ekalaka) [C] — 9 violations
• 59728 (Elliston) [D]
• 59915 (Elmo) [D]
• 59027 (Emigrant) [C] — 5 violations
• 59729 (Ennis) [B] — 1 violation
• 59916 (Essex) [D]
• 59435 (Ethridge) [C] — 2 violations
• 59917 (Eureka) [C] — 6 violations
• 59436 (Fairfield) [C] — 3 violations
• 59221 (Fairview) [C] — 2 violations
• 59326 (Fallon) [D]
• 59028 (Fishtail) [D]
• 59222 (Flaxville) [C] — 11 violations
• 59833 (Florence) [C] — 1 violation
• 59440 (Floweree) [D]
• 59441 (Forest Grove) [D]
• 59327 (Forsyth) [B]
• 59442 (Fort Benton) [C] — 4 violations
• 59636 (Fort Harrison) [C] — 6 violations
• 59223 (Fort Peck) [B] — 1 violation
• 59443 (Fort Shaw) [B]
• 59035 (Fort Smith) [F] — 36 violations ⚠
• 59918 (Fortine) [C] — 2 violations
• 59225 (Frazer) [D]
• 59834 (Frenchtown) [C] — 1 violation
• 59226 (Froid) [C]
• 59029 (Fromberg) [C] — 14 violations ⚠
• 59444 (Galata) [D] — 2 violations
• 59730 (Gallatin Gateway) [B] — 1 violation
• 59030 (Gardiner) [B] — 1 violation
• 59731 (Garrison) [D]
• 59031 (Garryowen) [D]
• 59446 (Geraldine) [C] — 6 violations ⚠
• 59447 (Geyser) [C]
• 59525 (Gildford) [C] — 1 violation
• 59230 (Glasgow) [F] — 42 violations
• 59732 (Glen) [D]
• 59330 (Glendive) [C] — 5 violations
• 59240 (Glentana) [D]
• 59733 (Gold Creek) [D]
• 59835 (Grantsdale) [D]
• 59032 (Grass Range) [C] — 4 violations
• 59401 (Great Falls) [C] — 13 violations ⚠
• 59403 (Great Falls) [D] — 13 violations ⚠
• 59404 (Great Falls) [D] — 13 violations ⚠
• 59405 (Great Falls) [C] — 13 violations ⚠
• 59406 (Great Falls) [C] — 13 violations ⚠
• 59033 (Greycliff) [B]
• 59837 (Hall) [D]
• 59840 (Hamilton) [B] — 1 violation
• 59332 (Hammond) [D]
• 59034 (Hardin) [C] — 19 violations
• 59526 (Harlem) [D] — 31 violations ⚠
• 59036 (Harlowton) [B] — 10 violations
• 59735 (Harrison) [D]
• 59333 (Hathaway) [D]
• 59842 (Haugan) [C] — 2 violations
• 59501 (Havre) [D] — 14 violations ⚠
• 59527 (Hays) [D]
• 59448 (Heart Butte) [D]
• 59601 (Helena) [D] — 36 violations ⚠
• 59602 (Helena) [F] — 36 violations ⚠
• 59604 (Helena) [D] — 36 violations ⚠
• 59620 (Helena) [F] — 36 violations ⚠
• 59623 (Helena) [F] — 36 violations ⚠
• 59624 (Helena) [F] — 36 violations ⚠
• 59625 (Helena) [F] — 36 violations ⚠
• 59626 (Helena) [F] — 36 violations ⚠
• 59843 (Helmville) [D]
• 59844 (Heron) [C] — 1 violation
• 59450 (Highwood) [C] — 20 violations ⚠
• 59451 (Hilger) [D]
• 59528 (Hingham) [C]
• 59241 (Hinsdale) [D] — 4 violations ⚠
• 59452 (Hobson) [C] — 2 violations
• 59529 (Hogeland) [D]
• 59242 (Homestead) [D]
• 59845 (Hot Springs) [D] — 2 violations
• 59919 (Hungry Horse) [C] — 4 violations
• 59037 (Huntley) [B] — 1 violation
• 59846 (Huson) [B] — 1 violation
• 59038 (Hysham) [C] — 17 violations ⚠
• 59039 (Ingomar) [D]
• 59530 (Inverness) [D]
• 59336 (Ismay) [D]
• 59736 (Jackson) [C] — 3 violations
• 59638 (Jefferson City) [D]
• 59041 (Joliet) [C] — 5 violations
• 59531 (Joplin) [D]
• 59337 (Jordan) [C] — 23 violations
• 59453 (Judith Gap) [B] — 1 violation
• 59901 (Kalispell) [C] — 4 violations
• 59903 (Kalispell) [C] — 4 violations
• 59904 (Kalispell) [C] — 4 violations
• 59454 (Kevin) [D]
• 59920 (Kila) [D]
• 59338 (Kinsey) [D]
• 59532 (Kremlin) [D]
• 59921 (Lake Mc Donald) [D]
• 59922 (Lakeside) [C]
• 59243 (Lambert) [D] — 10 violations
• 59043 (Lame Deer) [D]
• 59244 (Larslan) [D]
• 59044 (Laurel) [B] — 7 violations ⚠
• 59046 (Lavina) [D]
• 59456 (Ledger) [D] — 4 violations
• 59457 (Lewistown) [D] — 27 violations ⚠
• 59923 (Libby) [C] — 6 violations ⚠
• 59739 (Lima) [C]
• 59639 (Lincoln) [C] — 4 violations
• 59339 (Lindsay) [D]
• 59047 (Livingston) [C]
• 59535 (Lloyd) [D]
• 59050 (Lodge Grass) [C] — 4 violations
• 59847 (Lolo) [C] — 3 violations
• 59460 (Loma) [C]
• 59848 (Lonepine) [D]
• 59537 (Loring) [C]
• 59461 (Lothair) [D]
• 59402 (Malmstrom A F B) [D]
• 59538 (Malta) [C] — 12 violations
• 59741 (Manhattan) [C] — 10 violations
• 59925 (Marion) [B]
• 59926 (Martin City) [C]
• 59053 (Martinsdale) [C] — 2 violations
• 59640 (Marysville) [D]
• 59740 (Mc Allister) [D]
• 59052 (Mc Leod) [C]
• 59247 (Medicine Lake) [D]
• 59743 (Melrose) [D]
• 59054 (Melstone) [B] — 3 violations
• 59055 (Melville) [B]
• 59341 (Mildred) [D]
• 59301 (Miles City) [D] — 15 violations ⚠
• 59851 (Milltown) [C]
• 59801 (Missoula) [C] — 3 violations
• 59802 (Missoula) [C] — 3 violations
• 59803 (Missoula) [C] — 3 violations
• 59804 (Missoula) [C] — 3 violations
• 59806 (Missoula) [C] — 3 violations
• 59807 (Missoula) [C] — 3 violations
• 59808 (Missoula) [C] — 3 violations
• 59812 (Missoula) [C] — 3 violations
• 59462 (Moccasin) [D]
• 59057 (Molt) [D]
• 59463 (Monarch) [D]
• 59464 (Moore) [C] — 2 violations
• 59058 (Mosby) [D]
• 59059 (Musselshell) [B]
• 59248 (Nashua) [D] — 22 violations
• 59465 (Neihart) [C] — 2 violations
• 59745 (Norris) [D]
• 59853 (Noxon) [C]
• 59061 (Nye) [D]
• 59466 (Oilmont) [D]
• 59343 (Olive) [D]
• 59927 (Olney) [D]
• 59250 (Opheim) [C] — 1 violation ⚠
• 59062 (Otter) [D]
• 59252 (Outlook) [C] — 4 violations
• 59854 (Ovando) [D]
• 59855 (Pablo) [C] — 5 violations ⚠
• 59856 (Paradise) [C]
• 59063 (Park City) [C]
• 59253 (Peerless) [D]
• 59467 (Pendroy) [C]
• 59858 (Philipsburg) [F] — 15 violations ⚠
• 59841 (Pinesdale) [C]
• 59859 (Plains) [C] — 1 violation
• 59254 (Plentywood) [B]
• 59344 (Plevna) [C] — 2 violations
• 59746 (Polaris) [D]
• 59928 (Polebridge) [D]
• 59860 (Polson) [C] — 2 violations
• 59064 (Pompeys Pillar) [C]
• 59747 (Pony) [D]
• 59255 (Poplar) [D]
• 59345 (Powderville) [D]
• 59468 (Power) [C] — 4 violations
• 59065 (Pray) [C]
• 59929 (Proctor) [D]
• 59066 (Pryor) [D]
• 59641 (Radersburg) [D]
• 59748 (Ramsay) [C] — 7 violations
• 59067 (Rapelje) [C] — 1 violation
• 59863 (Ravalli) [D]
• 59256 (Raymond) [D]
• 59469 (Raynesford) [D]
• 59068 (Red Lodge) [C] — 3 violations
• 59257 (Redstone) [D]
• 59069 (Reed Point) [C]
• 59258 (Reserve) [D]
• 59930 (Rexford) [C]
• 59259 (Richey) [C] — 4 violations
• 59260 (Richland) [D]
• 59642 (Ringling) [D]
• 59070 (Roberts) [B] — 1 violation
• 59931 (Rollins) [C] — 2 violations
• 59864 (Ronan) [C] — 10 violations
• 59071 (Roscoe) [D]
• 59347 (Rosebud) [D]
• 59072 (Roundup) [D] — 1 violation
• 59073 (Roundup) [D] — 1 violation
• 59471 (Roy) [C] — 3 violations
• 59540 (Rudyard) [B] — 1 violation
• 59074 (Ryegate) [B] — 7 violations ⚠
• 59261 (Saco) [B] — 1 violation
• 59865 (Saint Ignatius) [D]
• 59231 (Saint Marie) [D]
• 59866 (Saint Regis) [D]
• 59075 (Saint Xavier) [C]
• 59867 (Saltese) [D]
• 59472 (Sand Coulee) [C] — 6 violations ⚠
• 59077 (Sand Springs) [D]
• 59076 (Sanders) [D]
• 59262 (Savage) [D]
• 59263 (Scobey) [D] — 1 violation
• 59868 (Seeley Lake) [C]
• 59078 (Shawmut) [C]
• 59474 (Shelby) [C] — 19 violations ⚠
• 59079 (Shepherd) [B] — 9 violations
• 59749 (Sheridan) [C] — 1 violation
• 59270 (Sidney) [D] — 18 violations ⚠
• 59081 (Silver Gate) [D]
• 59751 (Silver Star) [D]
• 59477 (Simms) [D]
• 59932 (Somers) [C] — 3 violations
• 59082 (Springdale) [D]
• 59479 (Stanford) [C] — 2 violations
• 59870 (Stevensville) [C] — 8 violations
• 59480 (Stockett) [C] — 3 violations
• 59933 (Stryker) [D]
• 59871 (Sula) [D]
• 59083 (Sumatra) [D]
• 59483 (Sun River) [C]
• 59482 (Sunburst) [C] — 8 violations ⚠
• 59872 (Superior) [B]
• 59484 (Sweet Grass) [F] — 8 violations ⚠
• 59084 (Teigen) [D]
• 59349 (Terry) [D]
• 59873 (Thompson Falls) [C] — 4 violations
• 59752 (Three Forks) [B] — 1 violation
• 59643 (Toston) [D]
• 59644 (Townsend) [C] — 2 violations
• 59934 (Trego) [D]
• 59874 (Trout Creek) [C]
• 59935 (Troy) [B]
• 59542 (Turner) [F] — 13 violations ⚠
• 59754 (Twin Bridges) [B]
• 59085 (Two Dot) [B] — 1 violation
• 59485 (Ulm) [B] — 1 violation
• 59486 (Valier) [C] — 6 violations
• 59273 (Vandalia) [D]
• 59487 (Vaughn) [C] — 6 violations
• 59875 (Victor) [D]
• 59274 (Vida) [D]
• 59755 (Virginia City) [C] — 13 violations ⚠
• 59351 (Volborg) [D]
• 59756 (Warm Springs) [D] — 9 violations
• 59936 (West Glacier) [C] — 1 violation
• 59758 (West Yellowstone) [C] — 4 violations
• 59275 (Westby) [C] — 1 violation
• 59645 (White Sulphur Springs) [C] — 8 violations
• 59937 (Whitefish) [C] — 1 violation
• 59759 (Whitehall) [D] — 22 violations ⚠
• 59276 (Whitetail) [D]
• 59544 (Whitewater) [D]
• 59545 (Whitlash) [D] — 4 violations
• 59353 (Wibaux) [C] — 17 violations ⚠
• 59354 (Willard) [D]
• 59760 (Willow Creek) [D]
• 59086 (Wilsall) [C] — 4 violations ⚠
• 59489 (Winifred) [C] — 4 violations ⚠
• 59087 (Winnett) [B] — 4 violations
• 59647 (Winston) [D]
• 59761 (Wisdom) [D]
• 59762 (Wise River) [D]
• 59648 (Wolf Creek) [F] — 29 violations ⚠
• 59201 (Wolf Point) [D]
• 59088 (Worden) [C]
• 59089 (Wyola) [D]
• 59546 (Zortman) [C] — 5 violations
• 59547 (Zurich) [D]

Data Sources

• Water quality: EPA Safe Drinking Water Information System (SDWIS)
• Regulations: State plumbing boards, ICC, IAPMO

Updated daily.

Frequently Asked Questions

Is the water safe to drink in Montana?

Montana has 442 community water systems serving 640,439 people across 405 ZIP codes. There are 2,102 recorded violations, including 431 health-based. 212 of 405 ZIP codes have at least one violation.

What plumbing code does Montana follow?

Montana follows the IPC plumbing code. DIY plumbing work is allowed for homeowners.

Is lead a concern in Montana's drinking water?

3 ZIP codes in Montana have lead levels exceeding the EPA action level of 0.015 mg/L.

What is the radon risk in Montana?

88% of ZIP codes in Montana fall in EPA Radon Zone 1 (highest risk).