Los Angeles County property record for 21504 Lost River Dr, Diamond Bar, CA 91765
| Property Type | Single Family Home |
|---|---|
| Details | 4 bd · 2 ba · 1,910 sqft · built 1963 |
| Lot Size | 0.2 acres (8,706 sqft) |
| Owner | 2 Company Names on Record |
| Last Sale | $218,000 (Aug 1998) |
| Tax Bill | $4,687 (2025) |
| Flood Zone | Zone X (minimal risk) |
| APN | 8285-004-016 |
| Primary APN | 8285-004-016 |
|---|
| Bedrooms | 4 Beds |
|---|---|
| Full Baths | 2 Baths |
| Total Rooms | 8 Rooms |
| Stories | 1 Story |
| Building Area | 1,910 sqft Living Area |
| Fireplaces | 1 Fireplace |
| Fireplace | Fireplace |
| Year Built | Built 1963 |
|---|---|
| Effective Year Built | Effective 1965 |
| Architectural Style | Conventional |
| Exterior Material | Stucco |
| Construction Type | Wood |
| Roof Type | Hip |
| Roof Material | Wood Shingle |
| Lot Area | 8,706 sqft (0.2 acres) |
| Heating System | Central |
|---|
| Street Address | 21504 LOST RIVER DR |
|---|---|
| City | DIAMOND BAR |
| State | CA |
| Zip | 91765-3126 |
| Property Category | Residential |
| Property Type | Residential > Single Family > Home |
| Local Zoning Code | LCR17500* |
| Legal Description | TRACT NO 25987 LOT 116 |
| Legal Subdivision | 25987 |
| Legal Tract | 25987 |
| Legal Block | 1 |
| Legal Lot Number | 116 |
| Jurisdiction | LOS ANGELES CA |
| Township / Civil Division | EAST SAN GABRIEL VALLEY |
| Census Block Group | 1 |
| Census Block | 1002 |
| Census Tract | 403325 |
Source: Los Angeles County records, as of August 25, 2026
Owner names and exact recorded amounts shown locked on this page are available instantly with a free trial.
| Owner of Record | 2 Company Names on Record |
|---|---|
| Mailing Address | 21504 LOST RIVER DR, DIAMOND BAR, CA 91765-3126 |
| Occupancy | Owner Occupied |
| Owner Type | Company |
| Vesting | Trust, Personal Trust |
| Deed Names | 2 Names on Deed |
|---|---|
| Last Sale | Aug 20, 1998 · Amount on Record |
| Deed Sale | Aug 20, 1998 · Amount on Record |
| Deed Document Number | 19981480865 |
| Prior Transfer Date | Jan 18, 1994 |
| Prior Transfer Doc | 0000196076 |
| Record Updated | Oct 29, 2026 |
Source: Los Angeles County assessment roll, as of August 25, 2026
| Type | Name |
|---|---|
| State | California |
| County | Los Angeles County |
| Municipality | Diamond Bar City |
| Unified School District | Walnut Valley Unified School District (KG - 12) |
| Year | Tax Bill | Assessed Value |
|---|---|---|
| 2026 | $348,574 (+2%) Land $159,896 Building $188,678 | |
| 2025 | $4,687.00 (+6.64%) Homeowner's exemption | $341,740 (+4.04%) Land $156,761 Building $184,979 |
| 2023 | $4,395.00 (+2.14%) Homeowner's exemption | $328,472 Land $150,675 Building $177,797 |
| 2022 | $4,303.00 |
Assessed value is set for property tax purposes and is not a market price estimate.
Source: FEMA National Flood Hazard Layer, effective September 30, 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 66% of the US · lower than 80% of California |
|---|---|
| Wildfire Likelihood | 0.02% 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 | WALNUT VALLEY WATER DISTRICT serves 100,941 people · EPA ID CA1910234 |
|---|---|
| Water Source | Purchased surface water from several systems |
| Last State Inspection | Jun 2023 |
| 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.
Source: FCC Broadband Data Collection, based on 437 locations within half a mile, as of December 31, 2025
| Provider | Max Down / Up (Mbps) |
|---|---|
| Frontier Fiber | 7,000 / 7,000 |
| Spectrum Cable | 1,000 / 35 |
| AT&T Fixed Wireless | 100 / 20 |
| T-Mobile Fixed Wireless | 100 / 20 |
May also be available: GeoLinks, Verizon.
Search by:
By searching, you agree to: Terms • Privacy • Disclosures