521 William Way, Martinez, CA 94553 Property Records

Contra Costa County property record for 521 William Way, Martinez, CA 94553

Property Summary

Property Type	Single Family Home
Details	4 bd · 3 ba · 2,815 sqft · built 2023
Lot Size	0.264 acres (11,480 sqft)
Owner	Individual Name on File
Last Sale	$1,471,000 (Dec 2023)
Tax Bill	$21,378 (2025)
Deeds & Mortgages	Dec 2023 Transfer Dec 2023 Sale
Flood Zone	Zone X (minimal risk)
APN	`162-580-036`

Property Details

APN / Parcel Number

Primary APN	`162-580-036`
Alternative APN	`162-580-036-0`

Interior

Bedrooms	4 Beds
Full Baths	3 Baths
Total Rooms	9 Rooms
Stories	2 Stories
Building Area	2,815 sqft Living Area
1st Floor Area	1,432 sqft
2nd Floor Area	1,383 sqft

Exterior

Year Built	Built 2023
Effective Year Built	Effective 2023
Lot Area	11,480 sqft (0.264 acres)
Garage Type	Attached
Garage Area	469 sqft
Parking Spaces	2 Parking Spaces

Location & Zoning

Street Address	521 WILLIAM WAY
City	MARTINEZ
State	CA
Zip	94553-4764
Property Category	Residential
Property Type	Residential > Single Family > Home
Legal Description	T9358 L36
Legal Subdivision	SUBDIVISION 9358 TRADITIONS/TH
Legal Tract	9358
Jurisdiction	CONTRA COSTA CA
Township / Civil Division	CENTRAL CONTRA COSTA
Census Block Group	3
Census Block	3014
Census Tract	321101

Owner

Source: Contra Costa County assessment roll, as of July 14, 2026

Owner names and exact recorded amounts shown locked on this page are available instantly with a free trial.

Owner of Record	Individual Name on File
Mailing Address	521 WILLIAM WAY, MARTINEZ, CA 94553-4764
Occupancy	Owner Occupied
Owner Type	Individual

Deeds, Mortgages & Sale History

Date	Document
Dec 4, 2023	Intrafamily Transfer, Transfer OLD REPUBLIC TITLE, OLD REPUBLIC TITLE COMPANY
Dec 4, 2023	Grant Deed, Transfer OLD REPUBLIC TITLE, OLD REPUBLIC TITLE COMPANY

Assessor's Deed Record

Deed Names	Verified Name on Deed
Last Sale	Dec 4, 2023 · Amount on Record
Deed Sale	Dec 4, 2023 · Amount on Record
Deed Document Number	2023128414
Prior Transfer Date	Nov 28, 2023
Prior Transfer Doc	0000128415
Record Updated	Sep 20, 2026

December 2023: Intrafamily Transfer, Transfer

Document Type	Intrafamily Transfer
Jurisdiction	CONTRA COSTA CA
Recording Date	Dec 4, 2023
Property Address	521 WILLIAM WAY, MARTINEZ, CA 94553-4764
Document Number	0000128415
Map Reference	MB 548 PG 21
Instrument Date	Nov 28, 2023
Instrument	2023-128415
Transaction Type	Transfer
Record Updated	Dec 13, 2023
Title Company	OLD REPUBLIC TITLE, OLD REPUBLIC TITLE COMPANY

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	521 WILLIAM WAY, MARTINEZ, CA 94553-4764

December 2023: Grant Deed, Transfer

Document Type	Grant Deed
Jurisdiction	CONTRA COSTA CA
Recording Date	Dec 4, 2023
Property Address	521 WILLIAM WAY, MARTINEZ, CA 94553-4764
Document Number	0000128414
Map Reference	MB 548 PG 21
Instrument Date	Nov 28, 2023
Instrument	2023-128414
Transaction Type	Transfer
Record Updated	Dec 13, 2023
Title Company	OLD REPUBLIC TITLE, OLD REPUBLIC TITLE COMPANY

Transaction

Amount	Amount Recorded
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
Address	521 WILLIAM WAY, MARTINEZ, CA 94553-4764

Tax Assessment & Valuation

Source: Contra Costa County assessment roll, as of July 14, 2026

Property Jurisdictions

Type	Name
State	California
County	Contra Costa County
Municipality	Martinez City
Unified School District	Mount Diablo Unified School District (KG - 12)

Tax Bill & Assessment History

Year	Tax Bill	Assessed Value
2026		$1,530,116 (+2%) Land $833,048 Building $697,068
2025	$21,378.00 (+292.4%) Homeowner's exemption	$1,500,114 (+596.51%) Land $816,714 Building $683,400
2023	$5,448.00 (+193.85%)	$215,377 Land $215,377
2022	$1,854.00

Assessed value and assessed market value are set for property tax purposes, not market price estimates; both are a fraction of this property's market value.

Flood

Source: FEMA National Flood Hazard Layer, effective October 12, 2026 · OpenFEMA NFIP redacted claims and policies, as of September 2026

FEMA Flood Zone	Zone X minimal risk
Flood Insurance Requirement	Not required lenders may require it
Nearby Flood Policies	1 in force

Values are read at the parcel center point; flood claims are located to the census block group, not this parcel; 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 99.8% of the US · lower than 99.8% of California
Wildfire Likelihood	Under 0.01% annual chance
Exposure	None beyond ember reach

Drinking Water

Source: EPA Safe Drinking Water Information System, as of September 2026

Water System	CITY OF MARTINEZ serves 31,015 people · EPA ID CA0710006
Water Source	Purchased surface water from CONTRA COSTA WATER DISTRICT
Last State Inspection	Oct 2025
Lead	Under 1 ppb (2023–2025) 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 558 locations within half a mile, as of December 31, 2025

Provider	Max Down / Up (Mbps)
Xfinity Cable	2,000 / 250
Unwired Fixed Wireless	300 / 25
T-Mobile USA Fixed Wireless	100 / 20
AT&T Fixed Wireless · DSL · Fiber in parts of the area	100 / 20

May also be available: Radiate Holdings, Verizon.

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