Boise County, Idaho
8 ZIP codes · Avg score 47/100 · Grade D · Updated 2026-06-04
In recent EPA cycles, Boise County's 8 ZIP codes show a persistent below-average water quality pattern — documented violations span multiple areas, have appeared consistently across recent reporting periods, and the compliance shortfalls are spread across the county rather than isolated to a single geographic pocket or utility district, suggesting a broader structural issue rather than a localized anomaly.
How Boise County Compares
How Boise County Compares
Boise County scores 19 points below the Idaho state average (66/100) and 21 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-04
ZIP Code Risk Map
Water Quality Map: Boise County, Idaho
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 13.3 (asthma 10.6%, diabetes 11.9%)
Estimated additional annual cost per homeowner: $1,594, driven primarily by wildfire
Infrastructure: 0.299% avg pipe failure probability, 13% of ZIPs at high risk
40.3% of homes built before 1978 (lead paint era)
Violation History (2022–2025)
↑ Worsening trendEPA violation counts by year across Boise County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 2 violations. Past 5 years: 6 total (6 health-based). Health-based violations are rising versus the prior 2-year window — worth closer monitoring.
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: $1,594
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
4,769 housing units in Boise 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 Boise County
Remediation costs are relatively manageable for most homeowners in Boise 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 Boise 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 Boise County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Idaho City Water Department | 478 | 10 |
| 2 | Duquette Pines Homeowners Association | 163 | 10 |
| 3 | HORSESHOE BEND WATER SUPPLY | 750 | 8 |
| 4 | Horseshu Vue Ranch Subd | 51 | 8 |
| 5 | Mountain View Water and Road Assn | 305 | 5 |
9 total water systems serve Boise County.
All ZIP Codes in Boise County
8 ZIP codes tracked in Boise County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 83622 | Garden Valley | 64 | C | 5 (3 health) | $504K |
| 2 | 83631 | Idaho City | 64 | C | 10 (2 health) | $374K |
| 3 | 83629 | Horseshoe Bend | 50 | D | 8 | $349K |
| 4 | 83602 | Banks | 40 | D | 0 | — |
| 5 | 83637 | Lowman | 40 | D | 0 | $180K |
| 6 | 83657 | Ola | 40 | D | 0 | $483K |
| 7 | 83666 | Placerville | 40 | D | 0 | — |
| 8 | 83670 | Sweet | 40 | D | 0 | $310K |
Recommended Buyer Guides for Boise County
Four sources — EPA, NSF, FEMA, CDC — drive the match.
- 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 Boise County, Idaho
Overview
Boise County in Idaho covers 8 ZIP codes with an average Home Safety Score of D (47/100).
3 of 8 ZIP codes have recorded EPA violations. 5 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.
What You Can Do
Boise 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
40.3% of homes in this county were built before 1978. Older plumbing and solder can leach lead into drinking water, especially in the morning.