Sonoma County, California
63 ZIP codes · Avg score 80/100 · Grade B · Updated 2026-06-03
Sonoma County — 63 ZIP codes, above-average safety grade.
How Sonoma County Compares
How Sonoma County Compares
Sonoma County scores 7 points above the California state average (73/100) and 12 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Sonoma County, California
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 11.2 (asthma 9.7%, diabetes 10.8%)
Estimated additional annual cost per homeowner: $3,259, driven primarily by sea_level
Infrastructure: 0.353% avg pipe failure probability, 24% of ZIPs at high risk
67.8% of homes built before 1978 (lead paint era)
Violation History (2021–2025)
↑ Worsening trendEPA violation counts by year across Sonoma County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 32 violations. Past 5 years: 54 total (54 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: $3,259
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
293,119 housing units in Sonoma 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 Sonoma County
Remediation costs are relatively manageable for most homeowners in Sonoma 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 Sonoma 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 Sonoma County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Bodega Bay Public Utility District | 1,069 | 27 |
| 2 | Valley Ford Water Association | 88 | 25 |
| 3 | EAST BAY MUD | 1,442,800 | 18 |
| 4 | Bella Vista Water Sys | 93 | 18 |
| 5 | Rapid River Mobilehome Park | 92 | 18 |
81 total water systems serve Sonoma County.
All ZIP Codes in Sonoma County
63 ZIP codes tracked in Sonoma County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 95406 | Santa Rosa | 99 | A | 1 | — |
| 2 | 95444 | Graton | 99 | A | 0 | $866K |
| 3 | 95419 | Camp Meeker | 98 | A | 0 | — |
| 4 | 95433 | El Verano | 97 | A | 0 | — |
| 5 | 94922 | Bodega | 95 | A | 0 | — |
| 6 | 94926 | Rohnert Park | 95 | A | 0 | — |
| 7 | 94927 | Rohnert Park | 95 | A | 0 | — |
| 8 | 94931 | Cotati | 95 | A | 0 | $788K |
| 9 | 95402 | Santa Rosa | 95 | A | 1 | — |
| 10 | 95409 | Santa Rosa | 95 | A | 1 | $808K |
| 11 | 95439 | Fulton | 95 | A | 0 | $818K |
| 12 | 94955 | Petaluma | 94 | A | 2 (1 health) | — |
| 13 | 94975 | Petaluma | 94 | A | 2 (1 health) | — |
| 14 | 94999 | Petaluma | 94 | A | 2 (1 health) | — |
| 15 | 95473 | Sebastopol | 94 | A | 2 (1 health) | — |
| 16 | 94928 | Rohnert Park | 92 | A | 0 | $635K |
| 17 | 94953 | Petaluma | 91 | A | 2 (1 health) | — |
| 18 | 94923 | Bodega Bay | 90 | A | 0 | $1178K |
| 19 | 95403 | Santa Rosa | 90 | A | 1 | $652K |
| 20 | 95404 | Santa Rosa | 90 | A | 1 | $866K |
| 21 | 95405 | Santa Rosa | 90 | A | 1 | $750K |
| 22 | 95407 | Santa Rosa | 90 | A | 1 | $603K |
| 23 | 95465 | Occidental | 89 | A | 2 | $1123K |
| 24 | 95441 | Geyserville | 88 | A | 1 | $1278K |
| 25 | 95452 | Kenwood | 88 | A | 1 | $969K |
| 26 | 95425 | Cloverdale | 87 | A | 1 | $647K |
| 27 | 94954 | Petaluma | 86 | A | 2 (1 health) | $790K |
| 28 | 95401 | Santa Rosa | 85 | A | 1 | $629K |
| 29 | 95421 | Cazadero | 85 | A | 1 | $643K |
| 30 | 95430 | Duncans Mills | 84 | B | 3 | — |
| 31 | 95448 | Healdsburg | 84 | B | 2 | $1030K |
| 32 | 95442 | Glen Ellen | 82 | B | 0 | $1361K |
| 33 | 95492 | Windsor | 82 | B | 0 | $778K |
| 34 | 95450 | Jenner | 81 | B | 1 | $798K |
| 35 | 95472 | Sebastopol | 81 | B | 2 (1 health) | $995K |
| 36 | 94952 | Petaluma | 76 | B | 2 (1 health) | $1017K |
| 37 | 94564 | Pinole | 73 | B | 0 | $697K |
| 38 | 94572 | Rodeo | 73 | B | 0 | $654K |
| 39 | 94580 | San Lorenzo | 73 | B | 0 | $820K |
| 40 | 94802 | Richmond | 73 | B | 0 | — |
| 41 | 95416 | Boyes Hot Springs | 73 | B | 0 | — |
| 42 | 95476 | Sonoma | 73 | B | 4 (1 health) | $882K |
| 43 | 94951 | Penngrove | 68 | C | 1 | $1213K |
| 44 | 95446 | Guerneville | 67 | C | 0 | $586K |
| 45 | 94556 | Moraga | 66 | C | 18 (14 health) | $1594K |
| 46 | 94807 | Richmond | 66 | C | 0 | — |
| 47 | 94808 | Richmond | 66 | C | 0 | — |
| 48 | 94820 | El Sobrante | 66 | C | 0 | — |
| 49 | 94850 | Richmond | 66 | C | 0 | — |
| 50 | 95412 | Annapolis | 66 | C | 0 | $746K |
| 51 | 95431 | Eldridge | 66 | C | 0 | — |
| 52 | 95480 | Stewarts Point | 66 | C | 0 | — |
| 53 | 95487 | Vineburg | 66 | C | 0 | — |
| 54 | 94801 | Richmond | 65 | C | 0 | $594K |
| 55 | 94803 | El Sobrante | 65 | C | 0 | $729K |
| 56 | 94804 | Richmond | 65 | C | 0 | $618K |
| 57 | 94805 | Richmond | 65 | C | 0 | $739K |
| 58 | 95486 | Villa Grande | 65 | C | 0 | — |
| 59 | 95436 | Forestville | 64 | C | 4 | $704K |
| 60 | 94806 | San Pablo | 60 | C | 0 | $582K |
| 61 | 94972 | Valley Ford | 60 | C | 25 (24 health) | — |
| 62 | 95471 | Rio Nido | 60 | C | 0 | $618K |
| 63 | 95462 | Monte Rio | 50 | D | 0 | $714K |
Recommended Buyer Guides for Sonoma County
Filtered against federal data, fitted to local risks.
- Best Water Filters for Lead — Lead above EPA action level in 1 ZIP code
- Best Lead Paint Test Kits — 67.8% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
Deep Dive Reports
Detailed analysis for Sonoma County, California
Overview
Sonoma County in California covers 63 ZIP codes with an average Home Safety Score of B (80/100).
29 of 63 ZIP codes have recorded EPA violations. 47 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.