Yolo County, California
19 ZIP codes · Avg score 84/100 · Grade B · Updated 2026-06-03
Yolo County earns a high water safety grade — 19 ZIP codes tracked, virtually all compliant.
How Yolo County Compares
How Yolo County Compares
Yolo County scores 11 points above the California state average (73/100) and 16 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Yolo County, California
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 9.8 (asthma 9.8%, diabetes 9.3%)
Estimated additional annual cost per homeowner: $1,596, driven primarily by flood
Infrastructure: 0.324% avg pipe failure probability, 26% of ZIPs at high risk
61.1% of homes built before 1978 (lead paint era)
Violation History (2022–2024)
→ Stable trendEPA violation counts by year across Yolo County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 10 violations. Past 5 years: 11 total (11 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: $1,596
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
87,971 housing units in Yolo 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 Yolo County
Remediation costs are relatively manageable for most homeowners in Yolo 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 Yolo 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 Yolo County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | City of Davis | 67,457 | 16 |
| 2 | Rolling Acres Mutual Water Company | 40 | 14 |
| 3 | Uc - Davis | 49,616 | 12 |
| 4 | City of West Sacramento | 53,355 | 8 |
| 5 | Madison Service District | 876 | 4 |
23 total water systems serve Yolo County.
All ZIP Codes in Yolo County
19 ZIP codes tracked in Yolo County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 95937 | Dunnigan | 95 | A | 1 | — |
| 2 | 95617 | Davis | 94 | A | 4 | — |
| 3 | 95798 | West Sacramento | 94 | A | 2 (1 health) | — |
| 4 | 95799 | West Sacramento | 94 | A | 2 (1 health) | — |
| 5 | 95605 | West Sacramento | 91 | A | 2 (1 health) | $376K |
| 6 | 95627 | Esparto | 87 | A | 0 | $478K |
| 7 | 95694 | Winters | 87 | A | 0 | $634K |
| 8 | 95618 | Davis | 86 | A | 4 | $840K |
| 9 | 95698 | Zamora | 86 | A | 1 (1 health) | $961K |
| 10 | 95776 | Woodland | 83 | B | 2 (1 health) | $555K |
| 11 | 95899 | Sacramento | 83 | B | 2 (1 health) | — |
| 12 | 95620 | Dixon | 82 | B | 0 | $595K |
| 13 | 95616 | Davis | 81 | B | 4 | $857K |
| 14 | 95691 | West Sacramento | 81 | B | 2 (1 health) | $532K |
| 15 | 95695 | Woodland | 78 | B | 2 (1 health) | $494K |
| 16 | 95606 | Brooks | 73 | B | 0 | — |
| 17 | 95637 | Guinda | 73 | B | 0 | $1012K |
| 18 | 95653 | Madison | 73 | B | 4 (1 health) | $321K |
| 19 | 95607 | Capay | 66 | C | 0 | $479K |
Recommended Buyer Guides for Yolo 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 Lead Paint Test Kits — 61.1% of homes built before 1978
- 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
Deep Dive Reports
Detailed analysis for Yolo County, California
Overview
Yolo County in California covers 19 ZIP codes with an average Home Safety Score of B (84/100).
13 of 19 ZIP codes have recorded EPA violations. 9 health-based violations have been documented.
← Back to California 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.