Ada County, Idaho
38 ZIP codes · Avg score 72/100 · Grade B · Updated 2026-06-03
Unlike many counties its size, Ada County keeps violation rates low — all 38 ZIP codes score at or above the state average for tap water safety, with no systemic concerns flagged in the current data set.
How Ada County Compares
How Ada County Compares
Ada County scores 6 points above the Idaho state average (66/100) and 4 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Ada County, Idaho
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 10.9 (asthma 10.3%, diabetes 9%)
Estimated additional annual cost per homeowner: $620, driven primarily by wildfire
Infrastructure: 0.354% avg pipe failure probability, 13% of ZIPs at high risk
Violation History (2023–2025)
→ Stable trendEPA violation counts by year across Ada County water systems. Health-based shown in red, total in blue.
Peak year: 2025 with 64 violations. Past 5 years: 104 total (104 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: $620
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 Ada County
Remediation costs are relatively manageable for most homeowners in Ada 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 Ada 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 Ada County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Veolia Water Idaho | 264,978 | 547 |
| 2 | Capitol Water Corporation | 9,000 | 528 |
| 3 | Idoc Sbx Complex | 3,309 | 527 |
| 4 | Idoc Idaho State Correctional Center | 2,204 | 527 |
| 5 | Hillsdale Estates Homeowners Assn | 800 | 527 |
26 total water systems serve Ada County.
All ZIP Codes in Ada County
38 ZIP codes tracked in Ada County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 83669 | Star | 79 | B | 1 | $536K |
| 2 | 83634 | Kuna | 76 | B | 2 | $415K |
| 3 | 83642 | Meridian | 75 | B | 6 (2 health) | $492K |
| 4 | 83646 | Meridian | 75 | B | 6 (2 health) | $488K |
| 5 | 83703 | Boise | 74 | B | 17 (3 health) | $477K |
| 6 | 83709 | Boise | 74 | B | 17 (3 health) | $441K |
| 7 | 83712 | Boise | 74 | B | 17 (3 health) | $758K |
| 8 | 83680 | Meridian | 73 | B | 6 (2 health) | — |
| 9 | 83701 | Boise | 72 | B | 17 (3 health) | — |
| 10 | 83704 | Boise | 72 | B | 17 (3 health) | $354K |
| 11 | 83705 | Boise | 72 | B | 17 (3 health) | $379K |
| 12 | 83707 | Boise | 72 | B | 17 (3 health) | — |
| 13 | 83708 | Boise | 72 | B | 17 (3 health) | — |
| 14 | 83711 | Boise | 72 | B | 17 (3 health) | — |
| 15 | 83713 | Boise | 72 | B | 17 (3 health) | $422K |
| 16 | 83715 | Boise | 72 | B | 17 (3 health) | — |
| 17 | 83717 | Boise | 72 | B | 17 (3 health) | — |
| 18 | 83719 | Boise | 72 | B | 17 (3 health) | — |
| 19 | 83720 | Boise | 72 | B | 17 (3 health) | — |
| 20 | 83721 | Boise | 72 | B | 17 (3 health) | — |
| 21 | 83722 | Boise | 72 | B | 17 (3 health) | — |
| 22 | 83724 | Boise | 72 | B | 17 (3 health) | — |
| 23 | 83725 | Boise | 72 | B | 17 (3 health) | — |
| 24 | 83726 | Boise | 72 | B | 17 (3 health) | — |
| 25 | 83727 | Boise | 72 | B | 17 (3 health) | — |
| 26 | 83728 | Boise | 72 | B | 17 (3 health) | — |
| 27 | 83729 | Boise | 72 | B | 17 (3 health) | — |
| 28 | 83730 | Boise | 72 | B | 17 (3 health) | — |
| 29 | 83731 | Boise | 72 | B | 17 (3 health) | — |
| 30 | 83732 | Boise | 72 | B | 17 (3 health) | — |
| 31 | 83735 | Boise | 72 | B | 17 (3 health) | — |
| 32 | 83756 | Boise | 72 | B | 17 (3 health) | — |
| 33 | 83757 | Boise | 72 | B | 17 (3 health) | — |
| 34 | 83799 | Boise | 72 | B | 17 (3 health) | — |
| 35 | 83702 | Boise | 69 | C | 17 (3 health) | $708K |
| 36 | 83706 | Boise | 69 | C | 17 (3 health) | $489K |
| 37 | 83616 | Eagle | 68 | C | 5 | $720K |
| 38 | 83714 | Garden City | 56 | C | 1 | $468K |
Recommended Buyer Guides for Ada County
Filtered against EPA monitoring data and CDC lead-exposure guidance, the guides below skip the generic catalog and connect directly to the contaminants and hazards on file here.
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best HEPA Air Purifiers for Wildfire Smoke — Wildfire is the top compound risk factor
Deep Dive Reports
Detailed analysis for Ada County, Idaho
Overview
Ada County in Idaho covers 38 ZIP codes with an average Home Safety Score of B (72/100).
38 of 38 ZIP codes have recorded EPA violations. 99 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.