STATE REPORT MT HEALTH VIOLATIONS: 28

Montana Home Safety Profiles by ZIP

405 ZIP codes · 97 water systems · IPC plumbing code

Data: ZipCheckup Home Safety Score model 4.0.0; EPA SDWIS, UCMR 5, EPA radon zones, EPA AirData, NWS, State plumbing boards, Rewiring America

ZipCheckup tracks drinking-water and home-safety data for 405 ZIP codes across Montana, covering 97 public water systems that serve about 530,174 people. 54 ZIP codes are mapped to at least one water system with an EPA violation on record.

405
ZIP Codes
97
Water Systems
54
ZIPs with Violations
IPC
Plumbing Code
C · 65
Avg Safety Score
1
ZIPs Mapped to a System Above the Lead Action Level
88%
EPA Radon Zone 1 (county-level potential)
#42
of 50 States
16%
ZIPs Rated A or B
81%
ZIPs with Violations
C
Montana average: 65/100 - ranked #42 of 50 states. 8 points below the national average (73). Water systems mapped to 81% of ZIP codes have recorded violations.

For the state of Montana, the average of ZIP-level scores falls short of a B on ZipCheckup's A-F scale.

Score Distribution

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

0
A
5
B
23
C
3
D
1
F
85-10070-8455-6940-540-39

Home Safety Scores by State

Loading map…
F (0-39) D (40-54) C (55-69) B (70-84) A (85+)

Model 4.0.0 inputs: EPA SDWIS, UCMR5 PFAS, EPA radon zones, annual county AQI •

Top 10 ZIP Codes by Home Safety Score in Montana

Highest Home Safety Scores in the state.

#ZIP CodeCityCountyScoreGrade
1 59102 BillingsYellowstone 83 B
2 59044 LaurelYellowstone 82 B
3 59105 BillingsYellowstone 80 B
4 59106 BillingsYellowstone 73 B
5 59101 BillingsYellowstone 72 B
6 59270 SidneyRichland 67 C
7 59725 DillonBeaverhead 67 C
8 59812 MissoulaMissoula 67 C
9 59834 FrenchtownMissoula 67 C
10 59840 HamiltonRavalli 67 C

10 Lowest-Scoring ZIP Codes in Montana

#ZIP CodeCityCountyScoreGradeViolations
1 59901 KalispellFlathead 35 F 38
2 59937 WhitefishFlathead 50 D 1
3 59602 HelenaLewis and Clark 50 D 133
4 59601 HelenaLewis and Clark 51 D 41
5 59923 LibbyLincoln 57 C 25
6 59912 Columbia FallsFlathead 59 C 23
7 59808 MissoulaMissoula 60 C 21
8 59860 PolsonLake 63 C 9
9 59714 BelgradeGallatin 63 C 10
10 59801 MissoulaMissoula 65 C 1

County Rankings

Water quality breakdown by county. 56 counties with data in Montana.

Loading county map…
F (0-39) D (40-54) C (55-69) B (70-84) A (85+)

County-level aggregation of measured ZIP Home Safety Scores • EPA SDWIS, UCMR 5 PFAS, EPA radon zones, EPA AirData

CountyAvg ScoreGradeZIPsBest ZIPWorst ZIP
30001 67 C 8 59725 (67) 59725 (67)
30003 N/A N/A 10 N/A N/A
30005 N/A N/A 7 N/A N/A
30007 N/A N/A 4 N/A N/A
30009 N/A N/A 10 N/A N/A
30011 N/A N/A 5 N/A N/A
30013 N/A N/A 19 N/A N/A
30015 N/A N/A 6 N/A N/A
30017 65 C 4 59301 (65) 59301 (65)
30019 N/A N/A 4 N/A N/A
30021 66 C 4 59330 (66) 59330 (66)
30023 N/A N/A 2 N/A N/A
30025 N/A N/A 3 N/A N/A
30027 66 C 10 59457 (66) 59457 (66)
30029 53 D 18 59911 (67) 59901 (35)
30031 65 C 14 59715 (66) 59714 (63)
30033 N/A N/A 5 N/A N/A
30035 N/A N/A 4 N/A N/A
30037 N/A N/A 2 N/A N/A
30039 N/A N/A 4 N/A N/A
30041 65 C 7 59501 (65) 59501 (65)
30043 N/A N/A 6 N/A N/A
30045 N/A N/A 5 N/A N/A
30047 63 C 11 59860 (63) 59860 (63)
30049 51 D 15 59601 (51) 59602 (50)
30051 N/A N/A 4 N/A N/A
30053 57 C 7 59923 (57) 59923 (57)
30055 N/A N/A 3 N/A N/A
30057 N/A N/A 11 N/A N/A
30059 N/A N/A 4 N/A N/A
30061 N/A N/A 5 N/A N/A
30063 65 C 18 59812 (67) 59808 (60)
30065 N/A N/A 4 N/A N/A
30067 N/A N/A 9 N/A N/A
30069 N/A N/A 2 N/A N/A
30071 N/A N/A 6 N/A N/A
30073 N/A N/A 5 N/A N/A
30075 N/A N/A 5 N/A N/A
30077 N/A N/A 7 N/A N/A
30079 N/A N/A 3 N/A N/A
30081 67 C 9 59840 (67) 59840 (67)
30083 67 C 5 59270 (67) 59270 (67)
30085 N/A N/A 6 N/A N/A
30087 N/A N/A 11 N/A N/A
30089 N/A N/A 9 N/A N/A
30091 N/A N/A 10 N/A N/A
30093 66 C 8 59701 (66) 59727 (66)
30095 N/A N/A 8 N/A N/A
30097 N/A N/A 3 N/A N/A
30099 N/A N/A 6 N/A N/A
30101 N/A N/A 8 N/A N/A
30103 N/A N/A 3 N/A N/A
30105 N/A N/A 11 N/A N/A
30107 N/A N/A 4 N/A N/A
30109 N/A N/A 1 N/A N/A
30111 78 B 23 59102 (83) 59101 (72)

Most Common Contaminants in Montana

Contaminant / RuleCategoryZIPs AffectedViolationsHealth Risk
Surface Water Treatment Rule Treatment Technique 31 83 No
Stage 1 DBP Rule Treatment Technique 24 58 Yes
Consumer Confidence Report Rule Reporting 23 44 Yes
Total Trihalomethanes (TTHM) Disinfection Byproducts 22 41 Yes
Arsenic Inorganic 18 32 Yes
Haloacetic Acids (HAA5) Disinfection Byproducts 17 21 Yes
Total Coliform Microbiological 12 18 No
PFOA PFAS 8 9 No

Overview

We track multi-source home safety signals for 405 ZIP records across Montana. Home Safety Score model 4.0.0 is published for 32 scored records; missing required evidence suppresses the score.

The EPA snapshots used for this build directly map water systems to 67 ZIP records, covering 97 community water systems that serve approximately 530,174 people.

54 of 67 ZIP codes with a reported violation count in the available EPA record (81%) have recorded EPA violations. 28 health-based violations appear in the available health breakdown.

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

ZIP Code City Home Safety Grade Violations Health-Based System
59602 Helena D 133 5 Helena Water System
59404 Great Falls — 82 2 City of Great Falls
59019 Columbus — 80 0 Country Haven Estates Whispering Pines
59069 Reed Point — 80 0 Country Haven Estates Whispering Pines
59601 Helena D 41 4 Helena Water System
59101 Billings B 38 2 City of Billings
59901 Kalispell F 38 2 Kalispell Public Works
59106 Billings B 34 2 City of Billings
59442 Fort Benton — 32 3 Tiber County Water District
59416 Brady — 28 3 Tiber County Water District

Areas with No Violations

ZIP Code City Home Safety Grade System Population
59037 Huntley — Lockwood Water and Sewer District 5,900
59047 Livingston — City of Livingston 7,500
59270 Sidney C City of Sidney 5,000
59401 Great Falls — City of Great Falls 60,000
59725 Dillon C City of Dillon 4,300
59812 Missoula C Missoula Water 68,200
59823 Bonner — Missoula Water 68,200
59834 Frenchtown C Missoula Water 68,200
59840 Hamilton C City of Hamilton 5,660
59911 Bigfork C Bigfork County Water and Sewer 6,100

Home Safety Score

Average Home Safety Score for Montana: C (65/100) across 32 scored of 405 tracked ZIP records.

Model 4.0.0 uses the canonical components water-compliance, pfas-mcl-screen, radon-zone, annual-aqi across 3 required domains. The sections below provide additional context and do not change that score. Missing required evidence suppresses the score, and a favorable result is not a property-level safety certification.

Lead & Copper

  • Average of reported 90th-percentile lead results: 0.0045 mg/L (EPA action level: 0.015 mg/L)
  • 1 of 67 ZIP codes with known status 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

ZIP Code City Population Safety Grade Violations
59101 Billings 133,413 B 38
59102 Billings 126,000 B 4
59106 Billings 115,513 B 34
59105 Billings 114,600 B 8
59718 Bozeman 73,728 C 1
59804 Missoula 71,864 — 4
59808 Missoula 71,422 C 21
59715 Bozeman 69,635 C 3
59802 Missoula 68,935 C 2
59405 Great Falls 68,850 — 5
59801 Missoula 68,413 C 1
59803 Missoula 68,371 C 2
59812 Missoula 68,200 C 0
59823 Bonner 68,200 — 0
59834 Frenchtown 68,200 C 0
59404 Great Falls 62,999 — 82
59414 Black Eagle 60,970 — 7
59401 Great Falls 60,000 — 0
59901 Kalispell 41,649 F 38
59602 Helena 40,378 D 133

Lowest Published Home Safety Scores

ZIP Code City Score Grade Violations
59901 Kalispell 35 F 38
59602 Helena 50 D 133
59937 Whitefish 50 D 1
59601 Helena 51 D 41
59923 Libby 57 C 25

Highest Published Home Safety Scores

ZIP Code City Score Grade Violations
59102 Billings 83 B 4
59044 Laurel 82 B 3
59105 Billings 80 B 8
59106 Billings 73 B 34
59101 Billings 72 B 38

All 405 ZIP Codes in Montana

Data Sources

Reporting periods vary by source. Missing data is shown as unavailable, not as zero.

Largest water systems in Montana

The 12 largest community water systems in Montana, out of 97 in our data.

Show all 12 water systems

Systems with the most violations in Montana

12 systems in Montana with the most recorded EPA violations.

Frequently Asked Questions

Is the water safe to drink in Montana?

Montana has 97 community water systems serving 530,174 people across 405 ZIP codes. There are 532 recorded violations among these water systems, including 28 health-based. 54 of 405 ZIP codes are mapped to at least one water system with a recorded violation.

What plumbing code does Montana follow?

Montana's listed plumbing code type is IPC as of our last review; local jurisdictions may adopt or amend codes. State rules allow homeowner plumbing work in some cases; check local permit and licensing rules before starting.

Is lead a concern in Montana's drinking water?

1 ZIP code in Montana is mapped to a water system whose reported 90th-percentile lead result exceeded the EPA action level of 0.015 mg/L.

What is the radon risk in Montana?

88% of ZIP codes in Montana are mapped to counties classified as EPA Radon Zone 1 (highest county-level radon potential).

How to cite this page

APA ZipCheckup. (2026). Montana Home Safety Profiles by ZIP. https://zipcheckup.com/states/montana/
BibTeX 
@misc{zipcheckup-states-montana,
  author = {{ZipCheckup}},
  title  = {{Montana Home Safety Profiles by ZIP}},
  year   = {2026},
  url    = {https://zipcheckup.com/states/montana/}
}

Page version: October 2026.

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