Alameda County property record for 4247 Gem Ave, Castro Valley, CA 94546
| Property Type | Single Family Home |
|---|---|
| Details | 3 bd · 1 ba · 1,080 sqft · built 1947 |
| Lot Size | 0.133 acres (5,775 sqft) |
| Owner | Company Name on Record |
| Last Sale | $755,000 (Jul 2025) |
| Tax Bill | $2,968 (2025) |
| Flood Zone | Zone X (minimal risk) |
| APN | 84C-669-53 |
| Primary APN | 84C-669-53 |
|---|---|
| Alternative APN |
|
| Bedrooms | 3 Beds |
|---|---|
| Full Baths | 1 Bath |
| Total Rooms | 6 Rooms |
| Stories | 1 Story |
| Building Area | 1,080 sqft Living Area |
| Fireplaces | 1 Fireplace |
| Fireplace | Fireplace |
| Year Built | Built 1947 |
|---|---|
| Effective Year Built | Effective 1947 |
| Architectural Style | L-Shape |
| Exterior Material | Wood Siding |
| Construction Type | Wood |
| Lot Area | 5,775 sqft (0.133 acres) |
| Heating System | Floor/Wall Furnace |
|---|---|
| Sewer | Municipal |
| Water Source | Commercial |
| Street Address | 4247 GEM AVE |
|---|---|
| City | CASTRO VALLEY |
| State | CA |
| Zip | 94546-4653 |
| Property Category | Residential |
| Property Type | Residential > Single Family > Home |
| Legal Description | LOT: 00015 BLK: 0002 TR: 0807 |
| Legal Subdivision | TR 807 |
| Legal Tract | 0807 |
| Legal Block | 2 |
| Legal Lot Number | 15 |
| Jurisdiction | ALAMEDA CA |
| Township / Civil Division | HAYWARD |
| Census Block Group | 3 |
| Census Block | 3011 |
| Census Tract | 430800 |
Source: Alameda County records, as of October 22, 2026
Owner names and exact recorded amounts shown locked on this page are available instantly with a free trial.
| Owner of Record | Company Name on Record |
|---|---|
| Mailing Address | 4737 HILLSIDE DR, CASTRO VALLEY, CA 94546-1406 |
| Owner Type | Company |
| Vesting | Limited Liability Partnership |
| Deed Names | Name on Deed |
|---|---|
| Last Sale | Jul 29, 2025 · Amount on Record |
| Deed Sale | Jul 29, 2025 · Amount on Record |
| Deed Document Number | 202595138 |
| Prior Transfer Date | Jul 22, 2025 |
| Prior Transfer Doc | 0000095137 |
| Record Updated | Oct 29, 2026 |
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 | Assessed Market Value |
|---|---|---|---|
| 2026 | $755,000 (+308.31%) Land $226,500 Building $528,500 | ||
| 2025 | $2,968.00 (+5.17%) Homeowner's exemption | $184,908 (+4.04%) Land $124,047 Building $60,861 | |
| 2023 | $2,822.00 Homeowner's exemption | $177,729 Land $119,231 Building $58,498 | $625,410 |
Assessed value and assessed market value are set for property tax purposes, not market price estimates; both are a fraction of this property's market value.
Source: FEMA National Flood Hazard Layer, effective May 25, 2026
| FEMA Flood Zone | Zone X minimal risk |
|---|---|
| Flood Insurance Requirement | Not required lenders may require it |
Values are read at the parcel center point; lenders make the official flood determination.
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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