Madison County, Idaho
4 ZIP codes · Avg score 82/100 · Grade B · Updated 2026-07-19
ZipCheckup grade for Madison: B.
This ZIP looks solid, with a few items worth a quick check.
Unlike many counties its size, Madison County keeps violation rates low - all 4 ZIP codes score at or above the state average for tap water safety, with no systemic concerns flagged in the current data set.
How Madison County Compares
How Madison County Compares
Madison County scores 16 points above the Idaho state average (66/100) and 14 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-07-19
Key Risk Factors
Health risk index: 8.3 (asthma 12.1%, diabetes 4.9%)
Estimated additional annual cost per homeowner: $908, driven primarily by flood
Infrastructure: 0.41% avg pipe failure probability, 50% of ZIPs at high risk
Violation History (2023–2024)
→ Stable trendEPA violation counts by year across Madison County water systems. Health-based shown in red, total in blue.
Peak year: 2023 with 24 violations. Past 5 years: 27 total (27 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: $908
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
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 serving Madison County
8 community water systems serving Madison County.
- B
- B
- B
- B
- B
- B
Show all 8 water systems
- B
- B
Systems with the most violations in Madison County
2 water systems with recorded EPA violations.
- B
- B
All ZIP Codes in Madison County
4 ZIP codes tracked in Madison County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 83440 | Rexburg | 82 | B | 13 (1 health) | $373K |
| 2 | 83441 | Rexburg | 82 | B | 13 (1 health) | — |
| 3 | 83460 | Rexburg | 82 | B | 13 (1 health) | — |
| 4 | 83448 | Sugar City | 81 | B | 1 | $331K |
Recommended Buyer Guides for Madison County
Editorial methodology pairs each documented risk in this county with the buyer category that addresses it, drawing on water-quality detections, housing-stock lead exposure, EPA Radon Zone designation, and FEMA flood and wildfire ratings. NSF-certified options surface where applicable, and products that match the specific contaminant take priority.
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best Sump Pumps — Flood is the top compound risk factor
- Best Mold Test Kits — Flood-driven moisture and mold risk
Overview
Madison County in Idaho covers 4 ZIP codes with an average Home Safety Score of B (82/100).
4 of 4 ZIP codes have recorded EPA violations. 3 health-based violations have been documented.
← Back to Idaho 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.