Franklin County, Idaho
7 ZIP codes · Avg score 76/100 · Grade B · Updated 2026-06-03
Franklin County's tap water quality puts it in the upper tier nationally; the 7 ZIP codes here record few health-based violations.
How Franklin County Compares
How Franklin County Compares
Franklin County scores 10 points above the Idaho state average (66/100) and 8 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Franklin County, Idaho
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 9.6%)
Estimated additional annual cost per homeowner: $977, driven primarily by energy_code_gap
Infrastructure: 0.4% avg pipe failure probability, 29% of ZIPs at high risk
58.1% of homes built before 1978 (lead paint era)
Violation History (2022–2025)
↓ Improving trendEPA violation counts by year across Franklin County water systems. Health-based shown in red, total in blue.
Peak year: 2023 with 10 violations. Past 5 years: 17 total (17 health-based). Health-based violations are declining versus the prior 2-year window.
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: $977
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
7,050 housing units in Franklin 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 Franklin County
Remediation costs are relatively manageable for most homeowners in Franklin 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 Franklin 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 Franklin County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | City of Preston | 5,591 | 40 |
| 2 | Fairview Water District | 1,300 | 25 |
| 3 | Whitney Nashville Water Works | 403 | 25 |
| 4 | Banida Winder Water and Sewer District | 180 | 25 |
| 5 | Cub River Acres | 180 | 25 |
11 total water systems serve Franklin County.
All ZIP Codes in Franklin County
7 ZIP codes tracked in Franklin County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 83286 | Weston | 83 | B | 0 | $322K |
| 2 | 83228 | Clifton | 82 | B | 6 (1 health) | $277K |
| 3 | 83232 | Dayton | 82 | B | 3 (1 health) | $291K |
| 4 | 83237 | Franklin | 81 | B | 15 (2 health) | $362K |
| 5 | 83263 | Preston | 81 | B | 25 (2 health) | $295K |
| 6 | 83252 | Malad City | 63 | C | 0 | $227K |
| 7 | 83281 | Swanlake | 63 | C | 0 | $304K |
Recommended Buyer Guides for Franklin County
Where county records show a lead exceedance or pre-1978 housing concentration, lead-specific filters and test kits move toward the top of the list.
- Best Lead Paint Test Kits — 58.1% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
Deep Dive Reports
Detailed analysis for Franklin County, Idaho
Overview
Franklin County in Idaho covers 7 ZIP codes with an average Home Safety Score of B (76/100).
4 of 7 ZIP codes have recorded EPA violations. 6 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.