Alameda County property record for 4271 Gem Ave, Castro Valley, CA 94546 · Last verified August 2026
| Property Type | Single Family Home |
|---|---|
| Details | 4 bd · 2 ba · 1,500 sqft · built 1947 |
| Lot Size | 0.133 acres (5,775 sqft) |
| Owner | 2 Individual Names on File |
| Last Sale | $64,090 (Jul 1995) |
| Tax Bill | $2,524 (2025) |
| Flood Zone | Zone X (minimal risk) |
| APN | 84C-669-61 |
| Primary APN | 84C-669-61 |
|---|---|
| Alternative APN |
|
| Bedrooms | 4 Beds |
|---|---|
| Full Baths | 2 Baths |
| Total Rooms | 8 Rooms |
| Stories | 1 Story |
| Building Area | 1,500 sqft Living Area |
| Year Built | Built 1947 |
|---|---|
| Effective Year Built | Effective 1947 |
| Architectural Style | L-Shape |
| Construction Type | Wood |
| Lot Area | 5,775 sqft (0.133 acres) |
| Street Address | 4271 GEM AVE |
|---|---|
| City | CASTRO VALLEY |
| State | CA |
| Zip | 94546-4654 |
| Property Category | Residential |
| Property Type | Residential > Single Family > Home |
| Legal Description | LOT: 00023 BLK: 0002 TR: 0807 |
| Legal Tract | 0807 |
| Legal Block | 2 |
| Legal Lot Number | 23 |
| Jurisdiction | ALAMEDA CA |
| Township / Civil Division | HAYWARD |
| Census Block Group | 3 |
| Census Block | 3011 |
| Census Tract | 430800 |
Source: Alameda County records · APN 84C-669-61
Assessment roll updated August 5, 2026 · Last verified August 2026
Owner names and exact recorded amounts shown locked on this page are available instantly with a free trial.
| Owner of Record | 2 Individual Names on File |
|---|---|
| Mailing Address | 4271 GEM AVE, CASTRO VALLEY, CA 94546-4654 |
| Occupancy | Owner Occupied |
| Owner Type | Individual |
| Deed Names | 2 Verified Names on Deed |
|---|---|
| Last Sale | Jul 12, 1995 · Amount on Record |
| Deed Sale | Jul 12, 1995 · Amount on Record |
| Deed Document Number | 1995151883 |
| Record Updated | Sep 20, 2026 |
Source: Alameda County records · Assessment roll updated August 5, 2026 · Last verified August 2026
| Type | Name |
|---|---|
| State | California |
| County | Alameda County |
| Unified School District | Castro Valley Unified School District (KG - 12) |
Assessed value and assessed market value are set for property tax purposes and are not market price estimates.
| Year | Tax Bill | Assessed Value | Assessed Market Value |
|---|---|---|---|
| 2026 | $143,173 (-2.75%) Land $46,207 Building $103,966 | ||
| 2025 | $2,524.00 (+5.52%) Homeowner's exemption | $147,229 (+4.04%) Land $45,301 Building $101,928 | |
| 2023 | $2,392.00 Homeowner's exemption | $141,512 Land $43,542 Building $97,970 | $745,200 |
Source: FEMA National Flood Hazard Layer, Alameda County (06001C), updated May 25, 2026 · USDA Forest Service Wildfire Risk to Communities, 2nd edition (2024), fuels as of 2020 · Last verified October 2026
| FEMA Flood Zone | Zone X |
|---|---|
| Special Flood Hazard Area | No |
| Flood Hazard | Minimal |
| 500-Year Floodplain | No |
| Wildfire Risk | Not rated no burnable land in reach |
|---|---|
| Wildfire Likelihood | Negligible |
| Exposure | None beyond ember reach |
Values are read at the parcel center point; lenders make the official flood determination.
Source: FCC Broadband Data Collection, availability as of December 31, 2025 · Published October 2026 · based on 777 locations within about half a mile of this property
| Provider | Technology | Download / Upload (Mbps) |
|---|---|---|
| Sonic Telecom | Fiber | 10,000 / 10,000 |
| AT&T | Fiber | 5,000 / 5,000 |
| Xfinity | Cable | 2,000 / 250 |
| Verizon | Fixed Wireless | 300 / 20 |
| Etheric Communications, LLC. | Fixed Wireless (licensed-by-rule) | 250 / 100 |
| T-Mobile USA | Fixed Wireless | 100 / 20 |
| AT&T | DSL | 100 / 20 |
May also be available at this address: AT&T, California Internet. Availability varies by address; speeds are provider-advertised maximums, not measured.
5G and 4G LTE
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