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521 9th Ave, San Mateo, CA 94402 Property Records

San Mateo County property record for 521 9th Ave, San Mateo, CA 94402

Property Summary

Property TypeDuplex
Details4 bd · 2 ba · 1,850 sqft · built 1955
Lot Size0.081 acres (3,520 sqft)
Owner2 Company Names on Record
Last Sale$290,000 (Jul 1997)
Tax Bill$8,769 (2025)
Deeds & MortgagesNov 2023 Transfer
Oct 2021 Transfer
Flood ZoneZone X (minimal risk)
APN033-282-260

Property Details

APN / Parcel Number

Primary APN033-282-260

Interior

Bedrooms4 Beds
Full Baths2 Baths
Total Rooms8 Rooms
Units2 Units
Stories1 Story
Building Area1,850 sqft Living Area
1st Floor Area1,850 sqft

Exterior

Year BuiltBuilt 1955
Effective Year BuiltEffective 1955
Architectural StyleDuplex Single
Lot Area3,520 sqft (0.081 acres)
Lot Dimensions128 ft deep x 27 ft wide
Parking Spaces2 Parking Spaces

Location & Zoning

Street Address521 9TH AVE
CitySAN MATEO
StateCA
Zip94402-1826
Property CategoryResidential
Property TypeResidential > Multi-Unit > Duplex
Local Zoning CodeRM0000
Legal DescriptionLOT 14 BLOCK 14 EAST SAN MATEO RSM 5/55 CITY OF SAN MATEO
Legal SubdivisionEAST SAN MATEO
Legal Block14
Legal Lot Number14
JurisdictionSAN MATEO CA
Township / Civil DivisionSAN MATEO
Census Block Group2
Census Block2013
Census Tract606300

Owner

Source: San Mateo County records, as of July 15, 2026

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

Owner of Record2 Company Names on Record
Mailing Address605 S DELAWARE ST, SAN MATEO, CA 94402-1356
Owner TypeCompany
VestingTrust

Deeds, Mortgages & Sale History

DateDocument
Nov 16, 2023Intrafamily Transfer, Transfer
Oct 12, 2021Intrafamily Transfer, Transfer

Assessor's Deed Record

Deed Names2 Names on Deed
Last SaleJul 18, 1997 · Amount on Record
Deed SaleJul 18, 1997 · Amount on Record
Deed Document Number199786542
Last Transfer DateApr 5, 2005
Transfer Doc0000081654
Record UpdatedOct 29, 2026

November 2023: Intrafamily Transfer, Transfer

Document TypeIntrafamily Transfer
JurisdictionSAN MATEO CA
Recording DateNov 16, 2023
Property Address521 9TH AVE, SAN MATEO, CA 94402-1826
Document Number0000061053
Map ReferenceMB 5 PG 55
Instrument DateNov 2, 2023
Instrument2023-061053
Transaction TypeTransfer
Record UpdatedDec 15, 2023

Transaction

Tax$0.00
Amount AccuracyTransfer Tax Exempt
Additional
  • Intrafamily Transfer

Transferred From (Grantor/Seller)

NameVerified Name

Transferred To (Grantee/Buyer)

NameVerified Name
RelationshipRevocable Trust
Address605 S DELAWARE ST, SAN MATEO, CA 94402-1356

October 2021: Intrafamily Transfer, Transfer

Document TypeIntrafamily Transfer
JurisdictionSAN MATEO CA
Recording DateOct 12, 2021
Property Address521 9TH AVE, SAN MATEO, CA 94402-1826
Document Number0000144333
Map ReferenceMB 5 PG 55
Instrument DateSep 21, 2021
Instrument2021-144333
Transaction TypeTransfer
Record UpdatedNov 3, 2021

Transaction

Tax$0.00
Amount AccuracyTransfer Tax Exempt
Additional
  • Intrafamily Transfer

Transferred From (Grantor/Seller)

NameVerified Name

Transferred To (Grantee/Buyer)

NameVerified Name
RelationshipTenants in Common
Address605 S DELAWARE ST, SAN MATEO, CA 94402-1356

Tax Assessment & Valuation

Source: San Mateo County assessment roll, as of July 15, 2026

Property Jurisdictions

TypeName
StateCalifornia
CountySan Mateo County
MunicipalitySan Mateo City
Elementary School DistrictSan Mateo-Foster City Elementary School District (KG - 08)
Secondary School DistrictSan Mateo Union High School District (09 - 12)

Tax Bill & Assessment History

YearTax BillAssessed Value
2026$472,298 (+2%) Land $146,570 Building $325,728
2025$8,769.00 (+5.88%) Homeowner's exemption$463,039 (+4.04%) Land $143,697 Building $319,342
2023$8,282.00 (+4.92%)$445,061 Land $138,118 Building $306,943
2022$7,894.00

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

Flood

Source: FEMA National Flood Hazard Layer, effective September 10, 2026

FEMA Flood ZoneZone X
minimal risk
Flood Insurance RequirementNot 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 RiskNot rated
no burnable land within 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 SystemCALIFORNIA WATER SERVICE - SAN MATEO
private · serves 103,536 people · EPA ID CA4110008
Water SourcePurchased surface water from SAN FRANCISCO REGIONAL WATER SYSTEM
Last State InspectionMar 2025
Lead4 ppb (2023–2025)
action level 15 ppb

Violations Reported to EPA

Water QualityNone
last 10 years
Treatment and ProcedureNone
last 10 years
Monitoring and ReportingNone
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 915 locations within half a mile, as of December 31, 2025

ProviderMax Down / Up (Mbps)
AT&T
Fiber · Fixed Wireless, DSL in parts of the area		5,000 / 5,000
Xfinity
Cable		2,000 / 250
Astound Broadband
Cable		1,500 / 50
Sonic Telecom
Fiber		1,000 / 1,000
Unwired
Fixed Wireless		300 / 25
Verizon
Fixed Wireless		300 / 20
Etheric Networks
Fixed Wireless		250 / 100
T-Mobile
Fixed Wireless		100 / 20

May also be available: GeoLinks.

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