Lake County, California
21 ZIP codes · Avg score 75/100 · Grade B · Updated 2026-06-03
Water utilities serving Lake County's 21 ZIP codes have built a consistent compliance record — the county's above-average grade reflects years of data showing low violation rates and no systemic health concerns.
How Lake County Compares
How Lake County Compares
Lake County scores 2 points above the California state average (73/100) and 7 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Lake County, California
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 13.6 (asthma 10.5%, diabetes 13.5%)
Estimated additional annual cost per homeowner: $2,649, driven primarily by wildfire
Infrastructure: 0.313% avg pipe failure probability, 11% of ZIPs at high risk
54.5% of homes built before 1978 (lead paint era)
Violation History (2021–2024)
→ Stable trendEPA violation counts by year across Lake County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 6 violations. Past 5 years: 17 total (17 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: $2,649
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
39,263 housing units in Lake 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 Lake County
Remediation costs are relatively manageable for most homeowners in Lake 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 Lake 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 Lake County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Cobb Area County Water District | 3,515 | 14 |
| 2 | Callayomi County Water District | 1,598 | 10 |
| 3 | Anderson Springs Csd | 373 | 10 |
| 4 | Lazy S Mobile Ranch | 73 | 10 |
| 5 | Mountain of Attention Water | 26 | 10 |
36 total water systems serve Lake County.
All ZIP Codes in Lake County
21 ZIP codes tracked in Lake County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 95443 | Glenhaven | 93 | A | 0 | — |
| 2 | 94522 | Concord | 91 | A | 4 (1 health) | — |
| 3 | 95426 | Cobb | 89 | A | 4 (2 health) | $348K |
| 4 | 95457 | Lower Lake | 89 | A | 2 | $414K |
| 5 | 95422 | Clearlake | 83 | B | 2 (2 health) | $206K |
| 6 | 95467 | Hidden Valley Lake | 82 | B | 0 | $394K |
| 7 | 95485 | Upper Lake | 81 | B | 3 (1 health) | $365K |
| 8 | 95453 | Lakeport | 80 | B | 0 | $371K |
| 9 | 95451 | Kelseyville | 78 | B | 0 | $341K |
| 10 | 95464 | Nice | 77 | B | 0 | $154K |
| 11 | 92657 | Newport Coast | 73 | B | 0 | $2000K |
| 12 | 95435 | Finley | 73 | B | 0 | — |
| 13 | 95679 | Rumsey | 73 | B | 0 | — |
| 14 | 92650 | East Irvine | 66 | C | 0 | — |
| 15 | 92698 | Aliso Viejo | 66 | C | 0 | — |
| 16 | 95493 | Witter Springs | 66 | C | 0 | $750K |
| 17 | 95424 | Clearlake Park | 65 | C | 0 | — |
| 18 | 95449 | Hopland | 65 | C | 0 | $597K |
| 19 | 95461 | Middletown | 65 | C | 10 (9 health) | $385K |
| 20 | 95423 | Clearlake Oaks | 60 | C | 0 | $285K |
| 21 | 95458 | Lucerne | 60 | C | 0 | $237K |
Recommended Buyer Guides for Lake County
Filtered against federal data, fitted to local risks.
- Best Lead Paint Test Kits — 54.5% of homes built before 1978
- 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 Lake County, California
Overview
Lake County in California covers 21 ZIP codes with an average Home Safety Score of B (75/100).
6 of 21 ZIP codes have recorded EPA violations. 15 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.