Alameda County property record for 18909 Masterson Pl, Castro Valley, CA 94552
| Property Type | Single Family Home |
|---|---|
| Details | 3 bd · 2.5 ba · 1,808 sqft · built 1985 |
| Lot Size | 0.125 acres (5,460 sqft) |
| Owner | 2 Individual Names on File |
| Last Sale | $630,000 (Sep 2004) |
| Tax Bill | $11,227 (2025) |
| Flood Zone | Zone X (minimal risk) |
| APN | 85A-6403-67 |
| Primary APN | 85A-6403-67 |
|---|---|
| Alternative APN |
|
| Bedrooms | 3 Beds |
|---|---|
| Full Baths | 2.5 Baths |
| Half Baths | 1 Half Bath |
| Total Rooms | 7 Rooms |
| Stories | 2 Stories |
| Building Area | 1,808 sqft Living Area |
| Year Built | Built 1985 |
|---|---|
| Effective Year Built | Effective 1985 |
| Architectural Style | L-Shape |
| Construction Type | Wood |
| Lot Area | 5,460 sqft (0.125 acres) |
| Street Address | 18909 MASTERSON PL |
|---|---|
| City | CASTRO VALLEY |
| State | CA |
| Zip | 94552-5083 |
| Property Category | Residential |
| Property Type | Residential > Single Family > Home |
| Legal Description | LOT: 00064 BLK: TR: 4468 |
| Legal Tract | 4468 |
| Legal Lot Number | 64 |
| Jurisdiction | ALAMEDA CA |
| Township / Civil Division | HAYWARD |
| Census Block Group | 3 |
| Census Block | 3003 |
| Census Tract | 430101 |
18909 Masterson Pl is owned and occupied by two individuals who bought it in September 2004.
Source: Alameda County records, as of August 5, 2026
| Owner of Record | 2 Individual Names on File |
|---|---|
| Mailing Address | 18909 MASTERSON PL, CASTRO VALLEY, CA 94552-5083 |
| Occupancy | Owner Occupied |
| Owner Type | Individual |
| Vesting | Community Property |
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 | 2 Names on Deed |
|---|---|
| Last Sale | Sep 28, 2004 · Amount on File |
| Deed Sale | Sep 28, 2004 · Amount on File |
| Prior Sale | Jan 27, 1998 · Amount on File |
| Deed Document Number | 2004439252 |
| Prior Transfer Date | Mar 2, 1994 |
| Prior Transfer Doc | 0000089952 |
| Record Updated | Oct 29, 2026 |
The 2025 property tax bill for 18909 Masterson Pl was $11,227.
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 | $895,354 (+2%) Land $268,549 Building $626,805 | ||
| 2025 | $11,227.00 | $877,802 Land $263,285 Building $614,517 | |
| 2023 | $10,811.00 | $843,723 Land $253,063 Building $590,660 | $1,165,500 |
Assessed value and assessed market value are set for property tax purposes and are not market price estimates.
FEMA maps place 18909 Masterson Pl in Zone X, an area of minimal flood risk, though there have been 2 flood claims nearby since 2017.
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 | 2 in force |
| Nearby Flood Claims | 2 (2017–2022) |
| Claims Outside the SFHA | 2 of 2 |
| Most Recent Claim | Dec 2022 · Severe Winter Storms, Flooding, Landslides, And Mudslides |
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 18909 Masterson Pl is high, ranking above 76% of the US, with a 0.5% annual chance of wildfire.
Source: USDA Forest Service Wildfire Risk to Communities (2nd edition), as of 2024
| Wildfire Risk | High above 76% of the US · above 52% of California |
|---|---|
| Wildfire Likelihood | 0.5% annual chance |
| Exposure | Indirect within ember reach |
| Adjoins Burnable Land | Yes |
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 411 locations within half a mile, as of December 31, 2025
| Provider | Max Down / Up (Mbps) |
|---|---|
| Xfinity Cable | 2,000 / 250 |
| Unwired Fixed Wireless | 300 / 25 |
| Verizon Fixed Wireless | 300 / 20 |
| T-Mobile Fixed Wireless | 100 / 20 |
| AT&T DSL | 100 / 20 |
May also be available: Etheric Networks.
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