Humboldt County, California
41 ZIP codes · Avg score 82/100 · Grade B · Updated 2026-06-04
Humboldt County earns a high water safety grade — 41 ZIP codes tracked, virtually all compliant.
How Humboldt County Compares
How Humboldt County Compares
Humboldt County scores 9 points above the California state average (73/100) and 14 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-04
ZIP Code Risk Map
Water Quality Map: Humboldt County, California
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 13.1 (asthma 11%, diabetes 11.8%)
Estimated additional annual cost per homeowner: $4,109, driven primarily by sea_level
Infrastructure: 0.363% avg pipe failure probability, 26% of ZIPs at high risk
65.5% of homes built before 1978 (lead paint era)
Violation History (2021–2024)
→ Stable trendEPA violation counts by year across Humboldt County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 25 violations. Past 5 years: 32 total (32 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: $4,109
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
62,924 housing units in Humboldt 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 Humboldt County
Remediation costs are relatively manageable for most homeowners in Humboldt 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 Humboldt 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 Humboldt County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Humboldt Bay Mwd | 680 | 18 |
| 2 | Weott C.s.d. | 448 | 15 |
| 3 | Phillipsville C.s.d. | 300 | 15 |
| 4 | City of Rio Dell, | 3,300 | 14 |
| 5 | Resort Improvement District #1 | 803 | 13 |
42 total water systems serve Humboldt County.
All ZIP Codes in Humboldt County
41 ZIP codes tracked in Humboldt County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 95511 | Alderpoint | 99 | A | 1 | — |
| 2 | 95518 | Arcata | 99 | A | 0 | — |
| 3 | 95534 | Cutten | 99 | A | 0 | — |
| 4 | 95551 | Loleta | 99 | A | 0 | $470K |
| 5 | 95553 | Miranda | 99 | A | 0 | $438K |
| 6 | 95525 | Blue Lake | 95 | A | 0 | $490K |
| 7 | 95560 | Redway | 95 | A | 1 | $364K |
| 8 | 95589 | Whitethorn | 95 | A | 1 | $439K |
| 9 | 95502 | Eureka | 94 | A | 4 (1 health) | — |
| 10 | 95526 | Bridgeville | 94 | A | 4 (1 health) | $338K |
| 11 | 95547 | Hydesville | 94 | A | 5 (1 health) | $489K |
| 12 | 95573 | Willow Creek | 94 | A | 3 (1 health) | $337K |
| 13 | 95570 | Trinidad | 92 | A | 4 | $599K |
| 14 | 95501 | Eureka | 91 | A | 4 (1 health) | $390K |
| 15 | 95542 | Garberville | 91 | A | 12 (1 health) | $414K |
| 16 | 95559 | Phillipsville | 91 | A | 15 (1 health) | — |
| 17 | 95521 | Arcata | 90 | A | 0 | $479K |
| 18 | 95555 | Orick | 89 | A | 0 | $400K |
| 19 | 95519 | Mckinleyville | 88 | A | 2 | $433K |
| 20 | 95540 | Fortuna | 87 | A | 7 (2 health) | $362K |
| 21 | 95562 | Rio Dell | 87 | A | 0 | $311K |
| 22 | 95503 | Eureka | 86 | A | 4 (1 health) | $412K |
| 23 | 95554 | Myers Flat | 86 | A | 2 (1 health) | $431K |
| 24 | 95565 | Scotia | 86 | A | 3 (1 health) | $350K |
| 25 | 95536 | Ferndale | 85 | A | 4 | $571K |
| 26 | 95524 | Bayside | 73 | B | 0 | $585K |
| 27 | 95571 | Weott | 73 | B | 0 | — |
| 28 | 95514 | Blocksburg | 66 | C | 0 | — |
| 29 | 95545 | Honeydew | 66 | C | 0 | $480K |
| 30 | 95546 | Hoopa | 66 | C | 0 | $253K |
| 31 | 95549 | Kneeland | 66 | C | 0 | $661K |
| 32 | 95550 | Korbel | 66 | C | 0 | $857K |
| 33 | 95552 | Mad River | 66 | C | 0 | $197K |
| 34 | 95558 | Petrolia | 66 | C | 0 | — |
| 35 | 95568 | Somes Bar | 66 | C | 0 | $281K |
| 36 | 95569 | Redcrest | 66 | C | 0 | $433K |
| 37 | 95587 | Piercy | 66 | C | 0 | — |
| 38 | 95595 | Zenia | 66 | C | 0 | $366K |
| 39 | 96031 | Forks Of Salmon | 66 | C | 0 | $189K |
| 40 | 95528 | Carlotta | 65 | C | 0 | $515K |
| 41 | 95556 | Orleans | 50 | D | 8 (4 health) | $324K |
Recommended Buyer Guides for Humboldt County
Four sources — EPA, NSF, FEMA, CDC — drive the match.
- Best Water Filters for Lead — Lead above EPA action level in 2 ZIP codes
- Best Lead Paint Test Kits — 65.5% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
Deep Dive Reports
Detailed analysis for Humboldt County, California
Overview
Humboldt County in California covers 41 ZIP codes with an average Home Safety Score of B (82/100).
18 of 41 ZIP codes have recorded EPA violations. 16 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.