21703 Lost River Dr, Diamond Bar, CA 91765 Property Records

Los Angeles County property record for 21703 Lost River Dr, Diamond Bar, CA 91765

Property Summary

Property Type	Single Family Home
Details	5 bd · 3 ba · 1,830 sqft · built 1963
Lot Size	0.196 acres (8,548 sqft)
Owner	Individual Name on File
Last Sale	$720,000 (Jul 2017)
Tax Bill	$10,511 (2025)
Deeds & Mortgages	May 2021 Transfer Jul 2017 Sale & Mortgage + 1 more
Flood Zone	Zone X (minimal risk)
APN	`8285-007-024`

Property Details

APN / Parcel Number

Primary APN	`8285-007-024`

Interior

Bedrooms	5 Beds
Full Baths	3 Baths
Total Rooms	9 Rooms
Stories	1 Story
Building Area	1,830 sqft Living Area
Fireplaces	1 Fireplace
Fireplace	Fireplace

Exterior

Year Built	Built 1963
Effective Year Built	Effective 1979
Architectural Style	Conventional
Exterior Material	Stucco
Construction Type	Wood
Roof Type	Hip
Roof Material	Gravel
Lot Area	8,548 sqft (0.196 acres)
Lot Dimensions	123 ft deep x 70 ft wide
Garage Type	Attached

Utilities, Heating & Cooling

Cooling System	Central
Heating System	Central
Water Source	Commercial

Location & Zoning

Street Address	21703 LOST RIVER DR
City	DIAMOND BAR
State	CA
Zip	91765-3130
Property Category	Residential
Property Type	Residential > Single Family > Home
Local Zoning Code	LCR17500*
Legal Description	TRACT NO 25987 LOT 97
Legal Subdivision	25987
Legal Tract	25987
Legal Block	1
Legal Lot Number	97
Jurisdiction	LOS ANGELES CA
Township / Civil Division	EAST SAN GABRIEL VALLEY
Census Block Group	1
Census Block	1003
Census Tract	403325

Owner

21703 Lost River Dr is owned and occupied by an individual who acquired it in April 2021.

Source: Los Angeles County records, as of August 25, 2026

Owner of Record	Individual Name on File
Mailing Address	21703 LOST RIVER DR, DIAMOND BAR, CA 91765-3130
Occupancy	Owner Occupied
Owner Type	Individual

Owner names and exact recorded amounts are on file and can be viewed instantly on this page with a free 10-day trial.

Deeds, Mortgages & Sale History

Date	Document
May 13, 2021	Intrafamily Transfer, Transfer
Jul 24, 2017	Grant Deed, Transfer · Conventional Mortgage TJ FINANCIAL INC
Jul 24, 2017	Quit Claim Deed, Transfer FIDELITY NATIONAL TITLE

Assessor's Deed Record

Deed Names	Name on Deed
Last Sale	Jul 24, 2017 · Amount on File
Deed Sale	Jul 24, 2017 · Amount on File
Prior Sale	Dec 10, 1993 · Amount on File
Deed Document Number	2017826562
Last Transfer Date	Apr 14, 2021
Transfer Doc	0000767515
Record Updated	Oct 29, 2026

May 2021: Intrafamily Transfer, Transfer

Document Type	Intrafamily Transfer
Jurisdiction	LOS ANGELES CA
Recording Date	May 13, 2021
Property Address	21703 LOST RIVER DR, DIAMOND BAR, CA 91765-3130
Document Number	0000767515
Map Reference	MB 694 PG 24-28
Instrument Date	Apr 14, 2021
Instrument	21-0767515
Transaction Type	Transfer
Record Updated	Jun 7, 2021

Transaction

Tax	$0.00
Amount Accuracy	Transfer Tax Exempt
Additional	Intrafamily Transfer

Transferred From (Grantor/Seller)

Name	Verified Name

Transferred To (Grantee/Buyer)

Name	Verified Name
Address	21703 LOST RIVER DR, DIAMOND BAR, CA 91765-3130

July 2017: Grant Deed, Transfer

Document Type	Grant Deed
Jurisdiction	LOS ANGELES CA
Recording Date	Jul 24, 2017
Property Address	21703 LOST RIVER DR, DIAMOND BAR, CA 91765-3130
Document Number	0000826562
Map Reference	MP694 PG24-28
Instrument Date	Jun 15, 2017
Instrument	17-0826562
Transaction Type	Transfer
Record Updated	Sep 22, 2021
Title Company	FIDELITY NATIONAL TITLE CO

Transaction

Amount	Amount on Record
Downpayment	Downpayment on Record
Loan-to-Value (LTV)	LTV on Record
Tax	$0.00
Amount Accuracy	Rounded by County
Additional	Arm's Length

Transferred From (Grantor/Seller)

Name	Verified Name

Transferred To (Grantee/Buyer)

Name	Verified Name
Relationship	Joint Tenants
Address	21703 LOST RIVER DR, DIAMOND BAR, CA 91765-3130

Mortgage

Document Number	0000826563
Date	Jul 24, 2017
Instrument	17-0826563

Lender

Name	TJ FINANCIAL INC
Type	Funding / Finance Company

Agreement

Type	Conventional Mortgage
Amount	Amount on Record
Term	361 Months
Due	Aug 1, 2047

July 2017: Quit Claim Deed, Transfer

Document Type	Quit Claim Deed
Jurisdiction	LOS ANGELES CA
Recording Date	Jul 24, 2017
Property Address	21703 LOST RIVER DR, DIAMOND BAR, CA 91765-3130
Document Number	0000826561
Instrument Date	May 23, 2017
Instrument	826561
Transaction Type	Transfer
Record Updated	Jul 27, 2017
Title Company	FIDELITY NATIONAL TITLE

Transaction

Tax	$0.00
Amount Accuracy	Full Value
Additional	Quitclaim Intrafamily Transfer

Transferred From (Grantor/Seller)

Name	Verified Name

Transferred To (Grantee/Buyer)

Name	Verified Name
Address	21703 LOST RIVER DR DIAMOND BAR CA 917653130, DIAMOND BAR, CA 91765-3130

Tax Assessment & Valuation

The 2025 property tax bill for 21703 Lost River Dr was $10,511 with a homeowner's exemption.

Source: Los Angeles County assessment roll, as of August 25, 2026

Property Jurisdictions

Type	Name
State	California
County	Los Angeles County
Municipality	Diamond Bar City
Unified School District	Walnut Valley Unified School District (KG - 12)

Tax Bill & Assessment History

Year	Tax Bill	Assessed Value
2026		$848,838 (+2%) Land $557,774 Building $291,064
2025	$10,511.00 Homeowner's exemption	$832,202 Land $546,838 Building $285,364
2023	$9,780.00 (+2.13%) Homeowner's exemption	$799,888 Land $525,604 Building $274,284
2022	$9,576.00

Assessed value is set for property tax purposes and is not a market price estimate.

Flood

FEMA maps place 21703 Lost River Dr in Zone X, an area of minimal flood risk.

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.

Wildfire

Wildfire risk around 21703 Lost River Dr is low, with a 0.02% 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	0.02% annual chance
Exposure	None beyond ember reach

Values cover an area roughly 900 ft across, not the parcel itself; insurers use their own ratings.

Drinking Water

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

Violations Reported to EPA

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.

Internet Providers

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.

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