Alameda County, California
75 ZIP codes · Avg score 69/100 · Grade C · Updated 2026-06-03
Across Alameda County's 75 ZIP codes, water safety results are uneven — a portion of systems carry active or recent violations, while others meet standards without issues.
How Alameda County Compares
How Alameda County Compares
Alameda County scores 4 points below the California state average (73/100) and 1 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Alameda 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 8.8%, diabetes 11%)
Estimated additional annual cost per homeowner: $2,328, driven primarily by sea_level
Infrastructure: 0.363% avg pipe failure probability, 37% of ZIPs at high risk
74.6% of homes built before 1978 (lead paint era)
Violation History (2023–2024)
→ Stable trendEPA violation counts by year across Alameda County water systems. Health-based shown in red, total in blue.
Peak year: 2023 with 30 violations. Past 5 years: 39 total (39 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: $2,328
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
645,514 housing units in Alameda 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 Alameda County
Remediation costs are relatively manageable for most homeowners in Alameda 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 Alameda 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 Alameda County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | EAST BAY MUD | 1,442,800 | 58 |
| 2 | Alameda Point | 1,400 | 52 |
| 3 | Camp Loma Mar | 208 | 52 |
| 4 | Brand Water Company | 112 | 52 |
| 5 | Point Cabrillo Highlands | 42 | 52 |
27 total water systems serve Alameda County.
All ZIP Codes in Alameda County
75 ZIP codes tracked in Alameda County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 94540 | Hayward | 83 | B | 0 | — |
| 2 | 94542 | Hayward | 83 | B | 0 | $1086K |
| 3 | 94543 | Hayward | 83 | B | 0 | — |
| 4 | 94545 | Hayward | 83 | B | 0 | $839K |
| 5 | 94551 | Livermore | 83 | B | 0 | $931K |
| 6 | 94557 | Hayward | 83 | B | 0 | — |
| 7 | 94552 | Castro Valley | 79 | B | 2 (1 health) | $1286K |
| 8 | 94606 | Oakland | 79 | B | 2 (1 health) | $748K |
| 9 | 94607 | Oakland | 79 | B | 2 (1 health) | $745K |
| 10 | 94609 | Oakland | 79 | B | 2 (1 health) | $1148K |
| 11 | 94612 | Oakland | 79 | B | 2 (1 health) | $814K |
| 12 | 94536 | Fremont | 78 | B | 8 (1 health) | $1210K |
| 13 | 94538 | Fremont | 78 | B | 8 (1 health) | $1105K |
| 14 | 94539 | Fremont | 78 | B | 8 (1 health) | $1878K |
| 15 | 94541 | Hayward | 78 | B | 0 | $782K |
| 16 | 94544 | Hayward | 78 | B | 0 | $802K |
| 17 | 94555 | Fremont | 78 | B | 8 (1 health) | $1295K |
| 18 | 94604 | Oakland | 78 | B | 2 (1 health) | — |
| 19 | 94613 | Oakland | 78 | B | 2 (1 health) | — |
| 20 | 94614 | Oakland | 78 | B | 2 (1 health) | — |
| 21 | 94615 | Oakland | 78 | B | 2 (1 health) | — |
| 22 | 94617 | Oakland | 78 | B | 2 (1 health) | — |
| 23 | 94622 | Oakland | 78 | B | 2 (1 health) | — |
| 24 | 94623 | Oakland | 78 | B | 2 (1 health) | — |
| 25 | 94624 | Oakland | 78 | B | 2 (1 health) | — |
| 26 | 94649 | Oakland | 78 | B | 2 (1 health) | — |
| 27 | 94659 | Oakland | 78 | B | 2 (1 health) | — |
| 28 | 94660 | Oakland | 78 | B | 2 (1 health) | — |
| 29 | 94661 | Oakland | 78 | B | 2 (1 health) | — |
| 30 | 94666 | Oakland | 78 | B | 2 (1 health) | — |
| 31 | 94537 | Fremont | 77 | B | 8 (1 health) | — |
| 32 | 94568 | Dublin | 77 | B | 0 | $1224K |
| 33 | 94546 | Castro Valley | 74 | B | 2 (1 health) | $976K |
| 34 | 94601 | Oakland | 74 | B | 2 (1 health) | $703K |
| 35 | 94602 | Oakland | 74 | B | 2 (1 health) | $1112K |
| 36 | 94603 | Oakland | 74 | B | 2 (1 health) | $596K |
| 37 | 94610 | Oakland | 74 | B | 2 (1 health) | $1325K |
| 38 | 94618 | Oakland | 74 | B | 2 (1 health) | $1789K |
| 39 | 94619 | Oakland | 74 | B | 2 (1 health) | $997K |
| 40 | 94621 | Oakland | 74 | B | 2 (1 health) | $538K |
| 41 | 94566 | Pleasanton | 73 | B | 2 (1 health) | $1592K |
| 42 | 94588 | Pleasanton | 73 | B | 2 (1 health) | $1277K |
| 43 | 94605 | Oakland | 69 | C | 2 (1 health) | $841K |
| 44 | 94611 | Oakland | 69 | C | 2 (1 health) | $1485K |
| 45 | 94560 | Newark | 63 | C | 0 | $1094K |
| 46 | 94586 | Sunol | 63 | C | 0 | $1558K |
| 47 | 94608 | Emeryville | 63 | C | 0 | $827K |
| 48 | 94702 | Berkeley | 63 | C | 0 | $1168K |
| 49 | 94703 | Berkeley | 63 | C | 0 | $1273K |
| 50 | 94704 | Berkeley | 63 | C | 0 | $919K |
| 51 | 94705 | Berkeley | 63 | C | 0 | $1892K |
| 52 | 94706 | Albany | 63 | C | 0 | $1188K |
| 53 | 94707 | Berkeley | 63 | C | 0 | $1627K |
| 54 | 94709 | Berkeley | 63 | C | 0 | $1241K |
| 55 | 94710 | Berkeley | 63 | C | 0 | $1085K |
| 56 | 95008 | Campbell | 63 | C | 0 | $1579K |
| 57 | 95659 | Nicolaus | 63 | C | 0 | $500K |
| 58 | 95843 | Antelope | 63 | C | 0 | $468K |
| 59 | 94577 | San Leandro | 58 | C | 0 | $825K |
| 60 | 94578 | San Leandro | 58 | C | 0 | $794K |
| 61 | 94501 | Alameda | 55 | C | 0 | $1213K |
| 62 | 94502 | Alameda | 55 | C | 0 | $1183K |
| 63 | 94530 | El Cerrito | 55 | C | 0 | $1097K |
| 64 | 94587 | Union City | 55 | C | 0 | $1058K |
| 65 | 94708 | Berkeley | 55 | C | 0 | $1517K |
| 66 | 95668 | Pleasant Grove | 55 | C | 0 | $618K |
| 67 | 94579 | San Leandro | 53 | D | 0 | $816K |
| 68 | 94620 | Piedmont | 53 | D | 0 | — |
| 69 | 94662 | Emeryville | 53 | D | 0 | — |
| 70 | 94701 | Berkeley | 53 | D | 0 | — |
| 71 | 94712 | Berkeley | 53 | D | 0 | — |
| 72 | 94720 | Berkeley | 53 | D | 0 | — |
| 73 | 95009 | Campbell | 53 | D | 0 | — |
| 74 | 95011 | Campbell | 53 | D | 0 | — |
| 75 | 95042 | New Almaden | 53 | D | 0 | — |
Recommended Buyer Guides for Alameda 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 Water Filters for Lead — Lead above EPA action level in 3 ZIP codes
- Best Lead Paint Test Kits — 74.6% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
Deep Dive Reports
Detailed analysis for Alameda County, California
Overview
Alameda County in California covers 75 ZIP codes with an average Home Safety Score of C (69/100).
35 of 75 ZIP codes have recorded EPA violations. 35 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.