Ventura County, California
45 ZIP codes · Avg score 58/100 · Grade C · Updated 2026-06-03
Across Ventura County, EPA compliance data for 45 ZIP codes sits at a moderate level — not alarming, but not uniformly clean either.
How Ventura County Compares
How Ventura County Compares
Ventura County scores 15 points below the California state average (73/100) and 10 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Ventura County, California
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 10.8 (asthma 9.5%, diabetes 11.4%)
Estimated additional annual cost per homeowner: $2,368, driven primarily by wildfire
Infrastructure: 0.328% avg pipe failure probability, 15% of ZIPs at high risk
Violation History (2022–2025)
→ Stable trendEPA violation counts by year across Ventura County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 31 violations. Past 5 years: 88 total (88 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: $2,368
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 Ventura County
Remediation costs are relatively manageable for most homeowners in Ventura 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 Ventura 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 Ventura County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Ventura Water Department | 113,500 | 92 |
| 2 | Del Norte Mutual Water Company | 215 | 89 |
| 3 | Rancho Sespe Workers Imp Assoc | 600 | 88 |
| 4 | Saticoy Country Club-city of Ventura | 196 | 88 |
| 5 | Shady Grove Mobile Home Park, Llc | 95 | 88 |
57 total water systems serve Ventura County.
All ZIP Codes in Ventura County
45 ZIP codes tracked in Ventura County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 93021 | Moorpark | 70 | B | 0 | $863K |
| 2 | 91358 | Thousand Oaks | 66 | C | 0 | — |
| 3 | 93011 | Camarillo | 66 | C | 1 | — |
| 4 | 93016 | Fillmore | 66 | C | 3 (1 health) | — |
| 5 | 93020 | Moorpark | 66 | C | 0 | — |
| 6 | 93031 | Oxnard | 66 | C | 3 (1 health) | — |
| 7 | 93033 | Oxnard | 66 | C | 3 (1 health) | $549K |
| 8 | 93061 | Santa Paula | 66 | C | 0 | — |
| 9 | 91360 | Thousand Oaks | 65 | C | 0 | $887K |
| 10 | 91362 | Thousand Oaks | 65 | C | 0 | $1078K |
| 11 | 91361 | Westlake Village | 64 | C | 0 | $1329K |
| 12 | 93004 | Ventura | 63 | C | 11 (4 health) | $751K |
| 13 | 93062 | Simi Valley | 62 | C | 3 | — |
| 14 | 93093 | Simi Valley | 62 | C | 3 | — |
| 15 | 93094 | Simi Valley | 62 | C | 3 | — |
| 16 | 93099 | Simi Valley | 62 | C | 3 | — |
| 17 | 93010 | Camarillo | 61 | C | 1 | $810K |
| 18 | 93012 | Camarillo | 61 | C | 1 | $794K |
| 19 | 93015 | Fillmore | 61 | C | 3 (1 health) | $590K |
| 20 | 93030 | Oxnard | 61 | C | 3 (1 health) | $640K |
| 21 | 93032 | Oxnard | 61 | C | 3 (1 health) | — |
| 22 | 93034 | Oxnard | 61 | C | 3 (1 health) | — |
| 23 | 93036 | Oxnard | 61 | C | 3 (1 health) | $649K |
| 24 | 93063 | Simi Valley | 61 | C | 3 | $746K |
| 25 | 93041 | Port Hueneme | 60 | C | 2 | $556K |
| 26 | 93060 | Santa Paula | 60 | C | 0 | $583K |
| 27 | 93022 | Oak View | 59 | C | 3 (1 health) | $705K |
| 28 | 93003 | Ventura | 58 | C | 11 (4 health) | $782K |
| 29 | 93002 | Ventura | 57 | C | 11 (4 health) | — |
| 30 | 93005 | Ventura | 57 | C | 11 (4 health) | — |
| 31 | 93006 | Ventura | 57 | C | 11 (4 health) | — |
| 32 | 93007 | Ventura | 57 | C | 11 (4 health) | — |
| 33 | 93009 | Ventura | 57 | C | 11 (4 health) | — |
| 34 | 93024 | Ojai | 56 | C | 4 (2 health) | — |
| 35 | 93035 | Oxnard | 56 | C | 3 (1 health) | $747K |
| 36 | 93065 | Simi Valley | 56 | C | 3 | $760K |
| 37 | 93044 | Port Hueneme | 53 | D | 2 | — |
| 38 | 93023 | Ojai | 52 | D | 4 (2 health) | $889K |
| 39 | 93001 | Ventura | 48 | D | 11 (4 health) | $761K |
| 40 | 91320 | Newbury Park | 45 | D | 0 | $918K |
| 41 | 91377 | Oak Park | 45 | D | 0 | $1017K |
| 42 | 91319 | Newbury Park | 40 | D | 0 | — |
| 43 | 93042 | Point Mugu Nawc | 40 | D | 0 | — |
| 44 | 93043 | Port Hueneme Cbc Base | 40 | D | 0 | — |
| 45 | 92101 | San Diego | 35 | F | 13 (4 health) | $741K |
Recommended Buyer Guides for Ventura County
Strictly editorial — no paid placements influence which guides appear; the selection draws on NSF certifications and EPA detection records for water systems serving this county.
- 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 Ventura County, California
Overview
Ventura County in California covers 45 ZIP codes with an average Home Safety Score of C (58/100).
32 of 45 ZIP codes have recorded EPA violations. 50 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.