Los Angeles County property record for 21603 Lost River Dr, Diamond Bar, CA 91765
| Property Type | Single Family Home |
|---|---|
| Details | 4 bd · 2 ba · 1,288 sqft · built 1963 |
| Lot Size | 0.231 acres (10,077 sqft) |
| Owner | 2 Individual Names on File |
| Tax Bill | $4,735 (2025) |
| Deeds & Mortgages | Oct 2017 Transfer Oct 2017 Transfer + 1 more |
| Flood Zone | Zone X (minimal risk) |
| APN | 8285-005-025 |
| Primary APN | 8285-005-025 |
|---|
| Bedrooms | 4 Beds |
|---|---|
| Full Baths | 2 Baths |
| Total Rooms | 9 Rooms |
| Stories | 1 Story |
| Building Area | 1,288 sqft Living Area |
| Fireplaces | 1 Fireplace |
| Fireplace | Fireplace |
| Year Built | Built 1963 |
|---|---|
| Effective Year Built | Effective 1963 |
| Architectural Style | Conventional |
| Exterior Material | Stucco |
| Construction Type | Wood |
| Roof Type | Gable |
| Roof Material | Wood Shingle |
| Lot Area | 10,077 sqft (0.231 acres) |
| Lot Dimensions | 141 ft deep x 72 ft wide |
| Heating System | Central |
|---|
| Street Address | 21603 LOST RIVER DR |
|---|---|
| City | DIAMOND BAR |
| State | CA |
| Zip | 91765-3128 |
| Property Category | Residential |
| Property Type | Residential > Single Family > Home |
| Local Zoning Code | LCR171/2 |
| Legal Description | TRACT NO 25987 LOT 91 |
| Legal Subdivision | 25987 |
| Legal Tract | 25987 |
| Legal Block | 1 |
| Legal Lot Number | 91 |
| Jurisdiction | LOS ANGELES CA |
| Township / Civil Division | EAST SAN GABRIEL VALLEY |
| Census Block Group | 1 |
| Census Block | 1003 |
| Census Tract | 403325 |
Source: Los Angeles County records · APN 8285-005-025
Assessment roll updated May 21, 2026 · Last verified June 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 | 21603 LOST RIVER DR, DIAMOND BAR, CA 91765-3128 |
| Occupancy | Owner Occupied |
| Owner Type | Individual |
| Vesting | Joint Tenants |
| Date | Document |
|---|---|
| Oct 24, 2017 | Quit Claim Deed, Transfer LAWYERS TITLE-OC |
| Oct 24, 2017 | Quit Claim Deed, Transfer LAWYERS TITLE-OC |
| Oct 24, 2017 | Quit Claim Deed, Transfer · Conventional Mortgage WESTERN EXPRESS LNDG |
| Deed Names | 2 Verified Names on Deed |
|---|---|
| Last Transfer Date | Oct 18, 2017 |
| Transfer Doc | 0001216164 |
| Record Updated | Sep 20, 2026 |
| Document Type | Quit Claim Deed |
|---|---|
| Jurisdiction | LOS ANGELES CA |
| Recording Date | Oct 24, 2017 |
| Property Address | 21603 LOST RIVER DR, DIAMOND BAR, CA 91765-3128 |
| Document Number | 0001216165 |
| Instrument Date | Oct 05, 2017 |
| Instrument | 1216165 |
| Transaction Type | Transfer |
| Record Updated | Oct 27, 2017 |
| Title Company | LAWYERS TITLE-OC |
| Tax | $0.00 |
|---|---|
| Additional |
|
| Name | Verified Name |
|---|
| Name | Verified Name |
|---|---|
| Relationship | Separate Estate/Property |
| Address | 21603 LOST RIVER DR DIAMOND BAR CA 917653128, DIAMOND BAR, CA 91765-3128 |
| Document Type | Quit Claim Deed |
|---|---|
| Jurisdiction | LOS ANGELES CA |
| Recording Date | Oct 24, 2017 |
| Property Address | 21603 LOST RIVER DR, DIAMOND BAR, CA 91765-3128 |
| Document Number | 0001216164 |
| Instrument Date | Oct 05, 2017 |
| Instrument | 1216164 |
| Transaction Type | Transfer |
| Record Updated | Oct 27, 2017 |
| Title Company | LAWYERS TITLE-OC |
| Tax | $0.00 |
|---|---|
| Additional |
|
| Name | Verified Name |
|---|
| Name | Verified Name |
|---|---|
| Relationship | Separate Estate/Property |
| Address | 21603 LOST RIVER DR DIAMOND BAR CA 917653128, DIAMOND BAR, CA 91765-3128 |
| Document Type | Quit Claim Deed |
|---|---|
| Jurisdiction | LOS ANGELES CA |
| Recording Date | Oct 24, 2017 |
| Property Address | 21603 LOST RIVER DR, DIAMOND BAR, CA 91765-3128 |
| Document Number | 0001216167 |
| Instrument Date | Sep 29, 2017 |
| Instrument | 1216167 |
| Transaction Type | Transfer |
| Record Updated | Oct 27, 2017 |
| Tax | $0.00 |
|---|---|
| Additional |
|
| Name | Verified Name |
|---|
| Name | Verified Name |
|---|---|
| Relationship | Joint Tenants with Right of Survivorship |
| Address | 21603 LOST RIVER DR DIAMOND BAR CA 917653128, DIAMOND BAR, CA 91765-3128 |
| Document Number | 1216166 |
|---|---|
| Date | Oct 24, 2017 |
| Instrument | 1216166 |
| Name | WESTERN EXPRESS LNDG |
|---|---|
| Address | IRVINE, CA 92618 |
| Type | Conventional Mortgage |
|---|---|
| Amount | Amount Recorded |
| Term | 360 Months |
| Due | Oct 23, 2047 |
Source: Los Angeles County records · Assessment roll updated May 21, 2026 · Last verified June 2026
| Type | Name |
|---|---|
| State | California |
| County | Los Angeles County |
| Municipality | Diamond Bar City |
| Unified School District | Walnut Valley Unified School District (KG - 12) |
Assessed value is set for property tax purposes and is not a market price estimate.
| Year | Tax Bill | Assessed Value |
|---|---|---|
| 2025 | $4,735.00 (+7.86%) Homeowner's exemption | $349,006 (+4.04%) Land $224,234 Building $124,772 |
| 2023 | $4,390.00 (+2.19%) Homeowner's exemption | $335,456 Land $215,528 Building $119,928 |
| 2022 | $4,296.00 |
Source: FEMA National Flood Hazard Layer as of September 30, 2026 · USDA Forest Service Wildfire Risk to Communities as of 2024 · Last verified October 2026
| FEMA Flood Zone | Zone X minimal risk |
|---|---|
| Flood Insurance Requirement | Not required lenders may require it |
| Wildfire Risk | Low lower than 80% of the US · lower than 88% of California |
|---|---|
| Wildfire Likelihood | 0.02% annual chance |
| Exposure | None beyond ember reach |
Values are read at the parcel center point; lenders make the official flood determination.
Source: FCC Broadband Data Collection as of December 31, 2025 · Last verified October 2026
| Provider | Max Down / Up (Mbps) |
|---|---|
| Frontier Fiber | 7,000 / 7,000 |
| Spectrum Cable | 1,000 / 35 |
| AT&T Fixed Wireless | 100 / 20 |
| T-Mobile USA Fixed Wireless | 100 / 20 |
May also be available: California Internet, Verizon.
Based on FCC filings for 437 locations within half a mile of this property.
Source: EPA Safe Drinking Water Information System as of 2026 Q3 · EPA water system boundaries as of March 2026 · Last verified October 2026
| Water System | WALNUT VALLEY WATER DISTRICT serves 100,941 people |
|---|---|
| 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 as reported to EPA, not water tested at this address; lead at the tap also depends on the building's own pipes. The full violation and enforcement history is in the system's EPA record.
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