21 Patten St, Sonoma, CA 95476 Property Records

Sonoma County property record for 21 Patten St, Sonoma, CA 95476

Property Summary

Property Type	Commercial Office
Details	2,531 sqft · built 1978
Lot Size	0.1 acres (4,356 sqft)
Owner	Company Name on Record
Tax Bill	$6,311 (2025)
Flood Zone	Zone X (moderate risk)
APN	`018-302-002-000`

Property Details

APN / Parcel Number

Primary APN	`018-302-002-000`
Alternative APN	`018-302-002`

Interior

Stories	2 Stories
Building Area	2,531 sqft Gross Area

Exterior

Year Built	Built 1978
Effective Year Built	Effective 1979
Architectural Style	Custom Design
Construction Type	Wood
Fire Resistance	Wood or Wood & Steel Frame
Lot Area	4,356 sqft (0.1 acres)
Garage Area	440 sqft

Utilities, Heating & Cooling

Cooling System	None

Location & Zoning

Old Parcel Number	018-302-002
Street Address	21 PATTEN ST
City	SONOMA
State	CA
Zip	95476-6704
Property Category	Commercial
Property Type	Commercial > Office > Commercial Office
Local Zoning Code	CCH
Legal Description	BUSINESS CODE: BE
Legal Subdivision	OFARRELLS
Legal Block	1
Legal Lot Number	72
Jurisdiction	SONOMA CA
Township / Civil Division	SONOMA
Census Block Group	1
Census Block	1006
Census Tract	150204

Historic Designation

Source: NPS National Register of Historic Places, as of August 1, 2026

Historic District	Within the Sonoma Plaza listed 1975 · 31 contributing resources · National Historic Landmark (designated 1960) · NRIS 75000489

Federal listing alone does not restrict alterations; local historic district rules, which this data does not cover, may apply.

Owner

Source: Sonoma County records, as of September 1, 2026

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

Owner of Record	Company Name on Record
Mailing Address	85 ADOBE WAY, SONOMA, CA 95476-3001
Owner Type	Company
Vesting	Trust

Deeds, Mortgages & Sale History

Assessor's Deed Record

Deed Names	Name on Deed
Last Transfer Date	Aug 24, 2007
Transfer Doc	0000105857
Record Updated	Oct 29, 2026

Tax Assessment & Valuation

Source: Sonoma County assessment roll, as of September 1, 2026

Property Jurisdictions

Type	Name
State	California
County	Sonoma County
Municipality	Sonoma City
Unified School District	Sonoma Valley Unified School District (KG - 12)

Tax Bill & Assessment History

Year	Tax Bill	Assessed Value
2026		$377,208 (+2%) Land $75,436 Building $301,772
2025	$6,311.00 (+6%)	$369,812 (+4.04%) Land $73,957 Building $295,855
2023	$5,954.00 (+2.41%)	$355,453 Land $71,086 Building $284,367
2022	$5,814.00

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

Flood

Source: FEMA National Flood Hazard Layer, effective February 15, 2026 · OpenFEMA NFIP redacted claims and policies, as of September 2026

FEMA Flood Zone	Zone X moderate risk
500-Year Floodplain	Yes 0.2% annual chance
Nearest Special Flood Hazard Area	Zone AE, within 500 ft
Flood Insurance Requirement	Not required lenders may require it
Flood Insurance Cost	Premium on Record median of 15 policies
Nearby Flood Policies	15 in force
Nearby Flood Claims	8 (1978–2025)
Claims Outside the SFHA	6 of 8
Most Recent Claim	Feb 2025 · rainfall accumulation
Claims by Event	Severe Winter Storms, Flooding, Landslides, And Mudslides, Feb 2019 · 2 claims Severe Winter Storm, Mud & Land Slides, & Flooding, Jan 1993 · 2 claims

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 80% of the US · lower than 88% of California
Wildfire Likelihood	0.01% 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	CITY OF SONOMA serves 10,619 people · EPA ID CA4910012
Water Source	Groundwater
Last State Inspection	Jul 2024
Lead	Under 1 ppb (2021–2023) action level 15 ppb

Violations Reported to EPA

Water Quality	None last 10 years
Treatment and Procedure	None last 10 years
Monitoring and Reporting	1 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 579 locations within half a mile, as of December 31, 2025

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