638 Mount St, Diamond Bar, CA 91765 Property Records

Los Angeles County property record for 638 Mount St, Diamond Bar, CA 91765

Property Summary

Property Type	Single Family Home
Details	4 bd · 3 ba · 2,610 sqft · built 1972
Lot Size	0.222 acres (9,662 sqft)
Owner	2 Individual Names on Record
Last Sale	$990,000 (Jun 2021)
Tax Bill	$14,383 (2025)
Deeds & Mortgages	Jun 2021 Sale & Mortgage Apr 2019 Mortgage + 3 more
Flood Zone	Zone X (minimal risk)
APN	`8717-021-019`

Property Details

APN / Parcel Number

Primary APN	`8717-021-019`

Interior

Bedrooms	4 Beds
Full Baths	3 Baths
Total Rooms	12 Rooms
Stories	2 Stories
Building Area	2,610 sqft Living Area
Fireplaces	1 Fireplace
Fireplace	Fireplace

Exterior

Year Built	Built 1972
Effective Year Built	Effective 1972
Architectural Style	Conventional
Exterior Material	Stucco
Construction Type	Wood
Roof Type	Gable
Roof Material	Wood Shingle
Lot Area	9,662 sqft (0.222 acres)
Lot Dimensions	135 ft deep x 72 ft wide
Garage Type	Attached

Utilities, Heating & Cooling

Cooling System	Central
Heating System	Central

Location & Zoning

Street Address	638 MOUNT ST
City	DIAMOND BAR
State	CA
Zip	91765-1938
Property Category	Residential
Property Type	Residential > Single Family > Home
Local Zoning Code	LCR118000*
Legal Description	TRACT NO 31139 LOT 19
Legal Subdivision	31139
Legal Tract	31139
Legal Block	2
Legal Lot Number	19
Jurisdiction	LOS ANGELES CA
Township / Civil Division	EAST SAN GABRIEL VALLEY
Census Block Group	2
Census Block	2001
Census Tract	403319

Owner

Source: Los Angeles County records, as of May 21, 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 Record
Mailing Address	638 MOUNT ST, DIAMOND BAR, CA 91765-1938
Occupancy	Owner Occupied
Owner Type	Individual
Vesting	Joint Tenants

Deeds, Mortgages & Sale History

Date	Document
Jun 15, 2021	Grant Deed, Transfer · Conventional Mortgage QUICKEN LOANS LLC
Apr 23, 2019	Deed of Trust, Mortgage · ARM FREMONT BANK
Apr 23, 2019	Deed of Trust, Mortgage · Line of Credit FREMONT BANK
Jul 7, 2020	Deed of Trust, Mortgage · Conventional Mortgage FIRST REPUBLIC BANK
Sep 17, 2020	Quit Claim Deed, Transfer NOT AVAILABLE

Assessor's Deed Record

Deed Names	2 Names on Deed
Last Sale	Jun 15, 2021 · Amount on Record
Deed Sale	Jun 15, 2021 · Amount on Record
Deed Document Number	2021943966
Prior Transfer Date	Aug 19, 2020
Prior Transfer Doc	0001129301
Record Updated	Sep 20, 2026

June 2021: Grant Deed, Transfer

Document Type	Grant Deed
Jurisdiction	LOS ANGELES CA
Recording Date	Jun 15, 2021
Property Address	638 MOUNT ST, DIAMOND BAR, CA 91765-1938
Document Number	0000943966
Map Reference	MB 817 PG 38-41
Instrument Date	Apr 19, 2021
Instrument	21-0943966
Transaction Type	Transfer
Record Updated	Jun 23, 2021
Title Company	WFG TITLE COMPANY OF CA

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	638 MOUNT ST, DIAMOND BAR, CA 91765-1938

Mortgage

Document Number	0000943967
Date	Jun 15, 2021
Instrument	21-0943967

Lender

Name	QUICKEN LOANS LLC
Type	Mortgage Company

Agreement

Type	Conventional Mortgage
Amount	Amount Recorded
Term	361 Months
Due	Jul 1, 2051

April 2019: Deed of Trust, Mortgage

Document Type	Deed of Trust
Jurisdiction	LOS ANGELES CA
Property Address	638 MOUNT ST, DIAMOND BAR, CA 91765-1938
Transaction Type	Mortgage
Record Updated	Feb 7, 2021
Title Company	CHICAGO TITLE COMPANY

Transferred To (Grantee/Buyer)

Name	Verified Name

Mortgage

Document Number	0000360928
Date	Apr 23, 2019
Instrument	19-0360928

Lender

Name	FREMONT BANK
Type	Bank
Address	LIVERMORE, CA 94551

Agreement

Type	ARM
Amount	Amount Recorded
Term	361 Months
Due	May 1, 2049

Interest

Rate Type	Adjustable Rate
Rate	4.12%
Type Change Date	May 1, 2026
Change Frequency	Annually
Min Rate At Change	2.87%
Max Rate At Change	9.12%
Index	1-Year LIBOR
Max Rate	9.12%

April 2019: Deed of Trust, Mortgage

Document Type	Deed of Trust
Jurisdiction	LOS ANGELES CA
Property Address	638 MOUNT ST, DIAMOND BAR, CA 91765-1938
Transaction Type	Mortgage
Record Updated	Feb 7, 2021

Transferred To (Grantee/Buyer)

Name	Verified Name

Mortgage

Document Number	0000360929
Date	Apr 23, 2019
Instrument	19-0360929

Lender

Name	FREMONT BANK
Type	Bank
Address	LIVERMORE, CA 94551

Agreement

Type	Line of Credit
Amount	Amount Recorded
Term	300 Months
Due	Apr 11, 2044

Interest

Rate Type	Adjustable Rate
Change Frequency	Monthly

July 2020: Deed of Trust, Mortgage

Document Type	Deed of Trust
Jurisdiction	LOS ANGELES CA
Property Address	638 MOUNT ST, DIAMOND BAR, CA 91765-1938
Transaction Type	Mortgage
Record Updated	Feb 5, 2021
Title Company	CHICAGO TITLE CO

Transferred To (Grantee/Buyer)

Name	Verified Name

Mortgage

Document Number	0000742084
Date	Jul 7, 2020
Instrument	20-0742084

Lender

Name	FIRST REPUBLIC BANK
Type	Bank
Address	SAN FRANCISCO, CA 94111

Agreement

Type	Conventional Mortgage
Amount	Amount Recorded
Term	360 Months
Due	Jul 1, 2050

Interest

Rate Type	Adjustable Rate
Rate	3.05%
Type Change Date	Jul 1, 2027
Change Frequency	Annually
Min Rate At Change	2.95%
Index	1-Year CMT
Max Rate	10.9%

September 2020: Quit Claim Deed, Transfer

Document Type	Quit Claim Deed
Jurisdiction	LOS ANGELES CA
Recording Date	Sep 17, 2020
Property Address	638 MOUNT ST, DIAMOND BAR, CA 91765-1938
Document Number	0001129301
Instrument Date	Aug 19, 2020
Instrument	1129301
Transaction Type	Transfer
Record Updated	Oct 19, 2020
Title Company	NOT AVAILABLE

Transaction

Tax	$0.00
Additional	Quitclaim Intrafamily Transfer

Transferred From (Grantor/Seller)

Name	Verified Name

Transferred To (Grantee/Buyer)

Name	Verified Name
Relationship	Revocable Trust
Address	638 MOUNT ST DIAMOND BAR CA 917651938, DIAMOND BAR, CA 91765-1938

Tax Assessment & Valuation

Source: Los Angeles County assessment roll, as of May 21, 2026

Property Jurisdictions

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

Tax Bill & Assessment History

Year	Tax Bill	Assessed Value
2025	$14,383.00 (+10.94%)	$1,071,605 (+4.04%) Land $696,869 Building $374,736
2023	$12,965.00 (+1.53%)	$1,029,995 Land $669,809 Building $360,186
2022	$12,769.00

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	Moderate above 46% of the US · lower than 72% of California
Wildfire Likelihood	0.08% annual chance
Exposure	Direct burnable vegetation

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 215 locations within half a mile, as of December 31, 2025

Provider	Max Down / Up (Mbps)
Spectrum Cable	1,000 / 1,000
AT&T Fixed Wireless	100 / 20

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

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