Madison County, Montana
11 ZIP codes · Avg score 53/100 · Grade D · Updated 2026-06-03
State safety rankings put Madison County near the bottom — 11 ZIP codes, below-average compliance.
How Madison County Compares
How Madison County Compares
Madison County scores 2 points below the Montana state average (55/100) and 15 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Madison County, Montana
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 12.8 (asthma 10.6%, diabetes 10.6%)
Estimated additional annual cost per homeowner: $717, driven primarily by wildfire
Infrastructure: 0.315% avg pipe failure probability, 18% of ZIPs at high risk
46.5% of homes built before 1978 (lead paint era)
Violation History (2023–2025)
→ Stable trendEPA violation counts by year across Madison County water systems. Health-based shown in red, total in blue.
Peak year: 2025 with 3 violations. Past 5 years: 5 total (5 health-based).
Source: EPA SDWIS historical violations. Data may lag 6–12 months for the most recent year.
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: $717
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
4,487 housing units in Madison 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 Madison County
Remediation costs are relatively manageable for most homeowners in Madison 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 Madison 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 Madison County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Virginia City Water Department | 1,500 | 13 |
| 2 | Western Mobile Village Dillon | 75 | 6 |
| 3 | ENNIS TOWN OF | 1,400 | 1 |
| 4 | Valley Garden Golf Village Hoa | 195 | 1 |
| 5 | Sheridan Town of | 632 | 1 |
6 total water systems serve Madison County.
All ZIP Codes in Madison County
11 ZIP codes tracked in Madison County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 59729 | Ennis | 70 | B | 1 | $475K |
| 2 | 59754 | Twin Bridges | 70 | B | 0 | $389K |
| 3 | 59749 | Sheridan | 66 | C | 1 | $348K |
| 4 | 59710 | Alder | 63 | C | 6 | $532K |
| 5 | 59755 | Virginia City | 61 | C | 13 (4 health) | $289K |
| 6 | 59745 | Norris | 53 | D | 0 | — |
| 7 | 59720 | Cameron | 40 | D | 0 | — |
| 8 | 59732 | Glen | 40 | D | 0 | — |
| 9 | 59740 | Mc Allister | 40 | D | 0 | $630K |
| 10 | 59743 | Melrose | 40 | D | 0 | $485K |
| 11 | 59751 | Silver Star | 40 | D | 0 | $200K |
Recommended Buyer Guides for Madison County
Retailer arrangements don't shape what appears here — the selection logic is independent, filtered against EPA detections and the federal hazard data on file for this county.
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
- Best HEPA Air Purifiers for Wildfire Smoke — Wildfire is the top compound risk factor
Deep Dive Reports
Detailed analysis for Madison County, Montana
Overview
Madison County in Montana covers 11 ZIP codes with an average Home Safety Score of D (53/100).
4 of 11 ZIP codes have recorded EPA violations. 4 health-based violations have been documented.
← 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.
What You Can Do
Madison County has a grade of D. Here are steps to protect your household.
Test your tap water
Order a certified lab test kit ($20-$50) to check for lead, bacteria, and other contaminants specific to your ZIP code.
Consider a certified water filter
NSF-certified filters can remove most common contaminants. Match the filter to your test results for best protection. Try our filter matcher
Contact your water utility
Request the latest Consumer Confidence Report (CCR) from your water provider. It details exactly what was found in your water supply.
Check for lead in your home
46.5% of homes in this county were built before 1978. Older plumbing and solder can leach lead into drinking water, especially in the morning.