Flathead County, Montana
18 ZIP codes · Avg score 57/100 · Grade C · Updated 2026-06-03
Flathead County's water quality grade reflects a middle-ground assessment — its 18 ZIP codes range from fully compliant to violation-flagged.
How Flathead County Compares
How Flathead County Compares
Flathead County scores 2 points above the Montana state average (55/100) and 11 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Flathead County, Montana
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 12.1 (asthma 10.7%, diabetes 9.3%)
Estimated additional annual cost per homeowner: $943, driven primarily by flood
Infrastructure: 0.305% avg pipe failure probability
49.2% of homes built before 1978 (lead paint era)
County Health Indicators vs National Average
Black markers indicate national averages. Source: CDC PLACES, Census ACS.
Infrastructure Overview
Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $943
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
52,008 housing units in Flathead County
Source: U.S. Census Bureau ACS B25034 (Year Structure Built).
Water Safety Affordability
How much it costs to fix water issues relative to home values in Flathead County
Remediation costs are relatively manageable for most homeowners in Flathead County, representing a small fraction of property value.
Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.
Health Outcomes vs National Average
CDC PLACES data for Flathead County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 5 systems in Flathead County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Kalispell Public Works | 25,000 | 13 |
| 2 | Flathead County Water and Sewer | 7,775 | 12 |
| 3 | Greenacres County Water and Sewer District | 450 | 12 |
| 4 | Country Estates Water Supply | 430 | 12 |
| 5 | Meadow Manor | 410 | 12 |
39 total water systems serve Flathead County.
All ZIP Codes in Flathead County
18 ZIP codes tracked in Flathead County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 59925 | Marion | 70 | B | 0 | $366K |
| 2 | 59922 | Lakeside | 66 | C | 0 | $549K |
| 3 | 59937 | Whitefish | 65 | C | 1 | $655K |
| 4 | 59919 | Hungry Horse | 64 | C | 4 | — |
| 5 | 59903 | Kalispell | 63 | C | 4 | — |
| 6 | 59904 | Kalispell | 63 | C | 4 | — |
| 7 | 59912 | Columbia Falls | 63 | C | 2 | $438K |
| 8 | 59913 | Coram | 63 | C | 3 | $533K |
| 9 | 59932 | Somers | 63 | C | 3 | $618K |
| 10 | 59901 | Kalispell | 62 | C | 4 | $417K |
| 11 | 59911 | Bigfork | 60 | C | 1 | $608K |
| 12 | 59936 | West Glacier | 56 | C | 1 | $563K |
| 13 | 59926 | Martin City | 55 | C | 0 | — |
| 14 | 59002 | Acton | 53 | D | 0 | $430K |
| 15 | 59916 | Essex | 40 | D | 0 | $361K |
| 16 | 59920 | Kila | 40 | D | 0 | $669K |
| 17 | 59921 | Lake Mc Donald | 40 | D | 0 | — |
| 18 | 59927 | Olney | 40 | D | 0 | $528K |
Recommended Buyer Guides for Flathead County
Four sources — EPA, NSF, FEMA, CDC — drive the match.
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
- Best Sump Pumps — Flood is the top compound risk factor
- Best Mold Test Kits — Flood-driven moisture and mold risk
Deep Dive Reports
Detailed analysis for Flathead County, Montana
Overview
Flathead County in Montana covers 18 ZIP codes with an average Home Safety Score of C (57/100).
10 of 18 ZIP codes have recorded EPA violations. All violations are monitoring/reporting type.
← Back to Montana water quality report
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Updated daily.