643 Alder Ln, Diamond Bar (Walnut), CA 91789 Property Records

Los Angeles County property record for 643 Alder Ln, Diamond Bar, CA 91789

Property Summary

Property Type	Planned Unit Development
Details	2 bd · 2 ba · 1,368 sqft · built 1986
Lot Size	0.033 acres (1,456 sqft)
Owner	2 Individual Names on Record
Last Sale	$448,000 (Nov 2017)
Tax Bill	$6,518 (2025)
Deeds & Mortgages	Jun 2020 Mortgage Nov 2017 Sale & Mortgage
Flood Zone	Zone X (minimal risk)
APN	`8719-018-052`

Property Details

APN / Parcel Number

Primary APN	`8719-018-052`

Interior

Bedrooms	2 Beds
Full Baths	2 Baths
Building Area	1,368 sqft Living Area

Exterior

Year Built	Built 1986
Effective Year Built	Effective 1986
Construction Type	Wood
Lot Area	1,456 sqft (0.033 acres)

Utilities, Heating & Cooling

Cooling System	Central
Heating System	Central

Location & Zoning

Street Address	643 ALDER LN
City	WALNUT
State	CA
Zip	91789-3346
Property Category	Residential
Property Type	Residential > Condominium / Townhouse > Planned Unit Development
Local Zoning Code	LCR312UDP*
Legal Description	TR=39833 LOT 52
Legal Subdivision	39833
Legal Tract	39833
Legal Block	3
Legal Lot Number	52
Jurisdiction	LOS ANGELES CA
Township / Civil Division	EAST SAN GABRIEL VALLEY
Census Block Group	3
Census Block	3001
Census Tract	403328

Owner

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

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

Owner of Record	2 Individual Names on Record
Mailing Address	1644 BEARS DEN RD, DIAMOND BAR, CA 91765-2607
Occupancy	Owner Occupied
Owner Type	Individual

Deeds, Mortgages & Sale History

Date	Document
Jun 10, 2020	Deed of Trust, Mortgage · Conventional Mortgage R M K FINANCIAL CORP
Nov 21, 2017	Grant Deed, Transfer · ARM ROYAL BUSINESS BANK

Assessor's Deed Record

Deed Names	2 Names on Deed
Last Sale	Nov 21, 2017 · Amount on Record
Deed Sale	Nov 21, 2017 · Amount on Record
Prior Sale	Apr 19, 2004 · Amount on Record
Deed Document Number	20171337180
Prior Transfer Date	Oct 24, 2015
Prior Transfer Doc	0001340616
Record Updated	Oct 29, 2026

June 2020: Deed of Trust, Mortgage

Document Type	Deed of Trust
Jurisdiction	LOS ANGELES CA
Property Address	643 ALDER LN, DIAMOND BAR, CA 91789-3346
Transaction Type	Mortgage
Record Updated	Feb 5, 2021
Title Company	FIDELITY NATIONAL TITLE CO

Transferred To (Grantee/Buyer)

Name	Verified Name

Mortgage

Document Number	0000628313
Date	Jun 10, 2020
Instrument	20-0628313

Lender

Name	R M K FINANCIAL CORP
Type	Mortgage Company
Address	ONTARIO, CA 91761

Agreement

Type	Conventional Mortgage
Amount	Amount Recorded
Term	361 Months
Due	Jul 1, 2050

November 2017: Grant Deed, Transfer

Document Type	Grant Deed
Jurisdiction	LOS ANGELES CA
Recording Date	Nov 21, 2017
Property Address	643 ALDER LN, DIAMOND BAR, CA 91789-3346
Document Number	0001337180
Map Reference	MB1035 PG38-41
Instrument Date	Oct 16, 2017
Instrument	17-1337180
Transaction Type	Transfer
Record Updated	Sep 22, 2021
Title Company	CORINTHIAN TITLE COMPANY

Transaction

Amount	Amount Recorded
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	643 ALDER LN, DIAMOND BAR, CA 91789-3346

Mortgage

Document Number	0001337181
Date	Nov 21, 2017
Instrument	17-1337181

Lender

Name	ROYAL BUSINESS BANK
Type	Bank

Agreement

Type	ARM
Amount	Amount Recorded
Term	361 Months
Due	Dec 1, 2047

Interest

Rate Type	Adjustable Rate
Rate	4.5%
Type Change Date	Dec 1, 2024
Change Frequency	Annually
Min Rate At Change	3.5%
Max Rate At Change	5.5%
Index	1-Year LIBOR
Max Rate	9.5%

Tax Assessment & Valuation

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		$519,936 (+2%) Land $232,114 Building $287,822
2025	$6,518.00 (+7.63%) Homeowner's exemption	$509,742 (+4.04%) Land $227,563 Building $282,179
2023	$6,056.00 (+2.19%) Homeowner's exemption	$489,950 Land $218,727 Building $271,223
2022	$5,926.00

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

Flood

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

Source: USDA Forest Service Wildfire Risk to Communities (2nd edition), as of 2024

Wildfire Risk	Low lower than 96% of the US · lower than 97.4% 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 200 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 / 1,000

May also be available: GeoLinks, T-Mobile, Verizon.

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