Alameda County property record for 4204 Gem Ave, Castro Valley, CA 94546
| Property Type | Single Family Home |
|---|---|
| Details | 5 bd · 3 ba · 1,978 sqft · built 1947 |
| Lot Size | 0.186 acres (8,085 sqft) |
| Owner | Individual Name on File |
| Last Sale | $455,000 (Feb 2014) |
| Tax Bill | $8,974 (2025) |
| Flood Zone | Zone X (minimal risk) |
| APN | 84C-669-38 |
| Primary APN | 84C-669-38 |
|---|---|
| Alternative APN |
|
| Bedrooms | 5 Beds |
|---|---|
| Full Baths | 3 Baths |
| Total Rooms | 8 Rooms |
| Units | 2 Units |
| Stories | 1 Story |
| Building Area | 1,978 sqft Living Area |
| Year Built | Built 1947 |
|---|---|
| Effective Year Built | Effective 1947 |
| Construction Type | Wood |
| Lot Area | 8,085 sqft (0.186 acres) |
| Street Address | 4204 GEM AVE |
|---|---|
| City | CASTRO VALLEY |
| State | CA |
| Zip | 94546-4617 |
| Property Category | Residential |
| Property Type | Residential > Single Family > Home |
| Legal Description | LOT: 00001 BLK: 0001 TR: 0807 |
| Legal Tract | 0807 |
| Legal Block | 1 |
| Legal Lot Number | 1 |
| Jurisdiction | ALAMEDA CA |
| Township / Civil Division | HAYWARD |
| Census Block Group | 4 |
| Census Block | 4000 |
| Census Tract | 430800 |
4204 Gem Ave is owned by an individual who bought it in February 2014.
Source: Alameda County records, as of September 28, 2026
| Owner of Record | Individual Name on File |
|---|---|
| Mailing Address | 4126 DAVID ST, CASTRO VALLEY, CA 94546-4624 |
| Owner Type | Individual |
| Vesting | Single Person |
Owner names and exact recorded amounts are on file and can be viewed instantly on this page with a free 10-day trial.
| Deed Names | Name on Deed |
|---|---|
| Last Sale | Feb 10, 2014 · Amount on File |
| Deed Sale | Feb 10, 2014 · Amount on File |
| Prior Sale | Sep 11, 2012 · Amount on File |
| Deed Document Number | 201446453 |
| Prior Transfer Date | Feb 6, 2014 |
| Prior Transfer Doc | 0000046454 |
| Record Updated | Oct 29, 2026 |
The 2025 property tax bill for 4204 Gem Ave was $8,974.
Source: Alameda County assessment roll, as of August 5, 2026
| Type | Name |
|---|---|
| State | California |
| County | Alameda County |
| Unified School District | Castro Valley Unified School District (KG - 12) |
| Year | Tax Bill | Assessed Value |
|---|---|---|
| 2026 | $637,163 (+2%) Land $170,668 Building $466,495 | |
| 2025 | $8,974.00 | $624,673 Land $167,323 Building $457,350 |
| 2023 | $8,583.00 | $600,421 Land $160,827 Building $439,594 |
Assessed value is set for property tax purposes and is not a market price estimate.
FEMA maps place 4204 Gem Ave in Zone X, an area of minimal flood risk.
Source: FEMA National Flood Hazard Layer, effective May 25, 2026 · OpenFEMA NFIP redacted claims and policies, as of September 2026
| FEMA Flood Zone | Zone X minimal risk |
|---|---|
| Flood Insurance Requirement | Not required lenders may require it |
| Community Rating System | Class 7 (15% premium discount) |
| Nearby Flood Policies | 1 in force |
Values are read at the parcel center point; flood claims are located to the census block group, not this parcel; lenders make the official flood determination.
Wildfire risk around 4204 Gem Ave is low, with a 0.01% annual chance of wildfire.
Source: USDA Forest Service Wildfire Risk to Communities (2nd edition), as of 2024
| Wildfire Risk | Low lower than 80% of the US · lower than 88% of California |
|---|---|
| Wildfire Likelihood | 0.01% annual chance |
| Exposure | None beyond ember reach |
Values cover an area roughly 900 ft across, not the parcel itself; insurers use their own ratings.
Source: EPA Safe Drinking Water Information System, as of September 2026
| Water System | EAST BAY MUD serves 1,468,000 people · EPA ID CA0110005 |
|---|---|
| Water Source | Surface water |
| Last State Inspection | Dec 2021 |
| Lead | Under 1 ppb (2022–2024) action level 15 ppb |
| Water Quality | None last 10 years |
|---|---|
| Treatment and Procedure | None last 10 years |
| Monitoring and Reporting | None last 3 years |
Results are for the whole water system, not water tested at this address; lead at the tap also depends on the building's own pipes. This system sells water to local utilities; the supplier billing this address may be one of them.
Source: FCC Broadband Data Collection, based on 777 locations within half a mile, as of December 31, 2025
| Provider | Max Down / Up (Mbps) |
|---|---|
| Sonic Telecom Fiber | 10,000 / 10,000 |
| AT&T Fiber · DSL · Fixed Wireless in parts of the area | 5,000 / 5,000 |
| Xfinity Cable | 2,000 / 250 |
| Verizon Fixed Wireless | 300 / 20 |
| Etheric Networks Fixed Wireless | 250 / 100 |
| T-Mobile Fixed Wireless | 100 / 20 |
May also be available: GeoLinks.
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