18521 Mountain Ln, Castro Valley, CA 94552 Property Records

Alameda County property record for 18521 Mountain Ln, Castro Valley, CA 94552

Property Summary

Property Type	Single Family Home
Details	4 bd · 2 ba · 1,669 sqft · built 1967
Lot Size	0.24 acres (10,449 sqft)
Owner	Trust Name on File
Tax Bill	$2,186 (2025)
Deeds & Mortgages	Oct 2023 Transfer Aug 2023 Transfer
Flood Zone	Zone X (minimal risk)
APN	`85-1605-64`

Property Details

APN / Parcel Number

Primary APN	`85-1605-64`
Alternative APN	`085-1605-064-00`

Interior

Bedrooms	4 Beds
Full Baths	2 Baths
Total Rooms	7 Rooms
Stories	1 Story
Building Area	1,669 sqft Living Area

Exterior

Year Built	Built 1967
Effective Year Built	Effective 1968
Architectural Style	L-Shape
Construction Type	Wood
Lot Area	10,449 sqft (0.24 acres)

Location & Zoning

Street Address	18521 MOUNTAIN LN
City	CASTRO VALLEY
State	CA
Zip	94552-1833
Property Category	Residential
Property Type	Residential > Single Family > Home
Legal Description	LOT: 00004 BLK: 000B TR: 2478
Legal Subdivision	E SHOWN ON THE MAP OF TRACT 2478
Legal Tract	2478
Legal Block	B
Legal Lot Number	4
Jurisdiction	ALAMEDA CA
Township / Civil Division	HAYWARD
Census Block Group	1
Census Block	1016
Census Tract	430102

Owner

18521 Mountain Ln is owner-occupied and held in a trust since October 2023.

Source: Alameda County records, as of August 5, 2026

Owner of Record	Trust Name on File
Mailing Address	18521 MOUNTAIN LN, CASTRO VALLEY, CA 94552-1833
Occupancy	Owner Occupied
Owner Type	Company
Vesting	Trust

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
Oct 25, 2023	Intrafamily Transfer, Transfer
Aug 29, 2023	Intrafamily Transfer, Transfer

Assessor's Deed Record

Deed Names	Name on Deed
Last Transfer Date	Oct 18, 2023
Transfer Doc	0000125766
Record Updated	Sep 20, 2026

October 2023: Intrafamily Transfer, Transfer

Document Type	Intrafamily Transfer
Jurisdiction	ALAMEDA CA
Recording Date	Oct 25, 2023
Property Address	18521 MOUNTAIN LN, CASTRO VALLEY, CA 94552-1833
Document Number	0000125766
Map Reference	MB 50 PG 25-28
Instrument Date	Oct 18, 2023
Instrument	2023125766
Transaction Type	Transfer
Record Updated	Dec 19, 2023

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	18521 MOUNTAIN LN, CASTRO VALLEY, CA 94552-1833

August 2023: Intrafamily Transfer, Transfer

Document Type	Intrafamily Transfer
Jurisdiction	ALAMEDA CA
Recording Date	Aug 29, 2023
Property Address	18521 MOUNTAIN LN, CASTRO VALLEY, CA 94552-1833
Document Number	0000098604
Map Reference	MB 50 PG 25-28
Instrument Date	Aug 25, 2023
Instrument	2023098604
Transaction Type	Transfer
Record Updated	Sep 27, 2023

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	18521 MOUNTAIN LN, CASTRO VALLEY, CA 94552-1833

Tax Assessment & Valuation

The 2025 property tax bill for 18521 Mountain Ln was $2,186 with a homeowner's exemption.

Source: Alameda County assessment roll, as of August 5, 2026

Property Jurisdictions

Type	Name
State	California
County	Alameda County
Unified School District	Castro Valley Unified School District (KG - 12)

Tax Bill & Assessment History

Year	Tax Bill	Assessed Value	Assessed Market Value
2026		$113,950 (-3.9%) Land $28,991 Building $91,959
2025	$2,186.00 Homeowner's exemption	$118,579 Land $28,423 Building $90,156
2023	$2,065.00 (+2.99%) Homeowner's exemption	$113,975 (+2%) Land $27,319 Building $86,656	$1,192,500
2022	$2,005.00 Homeowner's exemption	$111,741 Land $26,784 Building $84,957

Assessed value and assessed market value are set for property tax purposes and are not market price estimates.

Flood

FEMA maps place 18521 Mountain Ln in Zone X, an area of minimal flood risk.

Source: FEMA National Flood Hazard Layer, effective May 25, 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 18521 Mountain Ln is high, ranking above 71% of the US, with a 0.3% annual chance of wildfire.

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

Wildfire Risk	High above 71% of the US · above 46% of California
Wildfire Likelihood	0.3% annual chance
Exposure	Indirect within ember reach
Adjoins Burnable Land	Yes

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	EAST BAY MUD serves 1,468,000 people · EPA ID CA0110005
Water Source	Surface water
Last State Inspection	Dec 2021
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. This system sells water to local utilities; the supplier billing this address may be one of them.

Internet Providers

Source: FCC Broadband Data Collection, based on 389 locations within half a mile, as of December 31, 2025

Provider	Max Down / Up (Mbps)
AT&T Fiber · DSL in parts of the area	5,000 / 5,000
Xfinity Cable	2,000 / 250
Verizon Fixed Wireless	300 / 20
Etheric Networks Fixed Wireless	250 / 100
T-Mobile Fixed Wireless	100 / 20

May also be available: Unwired.

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