421 Boulder Dr, Antioch, CA 94509 Property Records

Contra Costa County property record for 421 Boulder Dr, Antioch, CA 94509

Property Summary

Property Type	Single Family Home
Details	4 bd · 2.5 ba · 2,152 sqft · built 1986
Lot Size	0.18 acres (7,860 sqft)
Owner	2 Individual Names on File
Tax Bill	$3,924 (2025)
Flood Zone	Zone X (minimal risk)
APN	`072-232-004-1`

Property Details

APN / Parcel Number

Primary APN	`072-232-004-1`
Alternative APN	`072-232-004`

Interior

Bedrooms	4 Beds
Full Baths	2.5 Baths
Half Baths	1 Half Bath
Total Rooms	10 Rooms
Stories	2 Stories
Building Area	2,152 sqft Living Area
1st Floor Area	1,140 sqft
2nd Floor Area	1,012 sqft

Exterior

Year Built	Built 1986
Effective Year Built	Effective 1986
Lot Area	7,860 sqft (0.18 acres)
Garage Type	Attached
Garage Area	504 sqft
Parking Spaces	2 Parking Spaces

Location & Zoning

Street Address	421 BOULDER DR
City	ANTIOCH
State	CA
Zip	94509-6907
Property Category	Residential
Property Type	Residential > Single Family > Home
Local Zoning Code	R1
Legal Description	T05614 L0042 B EX MR
Legal Tract	05614
Legal Lot Number	42
Jurisdiction	CONTRA COSTA CA
Township / Civil Division	ANTIOCH-PITTSBURG
Census Block Group	1
Census Block	1002
Census Tract	355109

Owner

Source: Contra Costa County records · APN 072-232-004-1

Assessment roll updated July 14, 2026 · Last verified July 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 File
Mailing Address	421 BOULDER DR, ANTIOCH, CA 94509-6907
Occupancy	Owner Occupied
Owner Type	Individual
Vesting	Joint Tenants

Deeds, Mortgages & Sale History

Assessor's Deed Record

Deed Names	2 Verified Names on Deed
Record Updated	Sep 20, 2026

Tax Assessment & Valuation

Source: Contra Costa County records · Assessment roll updated July 14, 2026 · Last verified July 2026

Property Jurisdictions

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

Tax Bill & Assessment History

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

Year	Tax Bill	Assessed Value
2026		$309,425 (+2%) Land $74,250 Building $235,175
2025	$3,924.00 (+5.51%) Homeowner's exemption	$303,359 (+4.04%) Land $72,795 Building $230,564
2023	$3,719.00 (+1.56%) Homeowner's exemption	$291,581 Land $69,969 Building $221,612
2022	$3,662.00

Flood & Wildfire

Source: FEMA National Flood Hazard Layer as of October 12, 2026 · USDA Forest Service Wildfire Risk to Communities as of 2024 · Last verified October 2026

Flood

FEMA Flood Zone	Zone X minimal risk
Flood Insurance Requirement	Not required lenders may require it

Wildfire

Wildfire Risk	Low lower than 80% of the US · lower than 88% of California
Wildfire Likelihood	0.01% annual chance
Exposure	None beyond ember reach

Values are read at the parcel center point; lenders make the official flood determination.

Internet Providers

Source: FCC Broadband Data Collection as of December 31, 2025 · Last verified October 2026

Provider	Max Down / Up (Mbps)
Xfinity Cable	2,000 / 250
Unwired Fixed Wireless	300 / 25
AT&T DSL	100 / 20

May also be available: Verizon.

Based on FCC filings for 645 locations within half a mile of this property.

Drinking Water

Source: EPA Safe Drinking Water Information System as of 2026 Q3 · EPA water system boundaries as of March 2026 · Last verified October 2026

Water System	CITY OF ANTIOCH serves 116,781 people
Water Source	Surface water
Last State Inspection	Jan 2024
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 as reported to EPA, not water tested at this address; lead at the tap also depends on the building's own pipes. The full violation and enforcement history is in the system's EPA record.