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Duplex (2 Units, Any Combination)Residential
Last sold for $995,000 on Dec 10, 2004

23 12TH AVE

SAN MATEO, CA 94402
5
Beds
2.5
Baths
2,104 ft²
Living AreaTotal finished area of the structures, from county records. Some counties include shared space like hallways or a building gym, so it may not match a listing.
0.14 ac
Lot SizeThe size of the land the home sits on, from county records.
1924
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
9
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.
2
ParkingThe number of parking spaces on the property, including the garage.

Valuation

Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$995,000 · Dec 10, 2004

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$19,699 (2025)
Assessed ValueThe value the county assigns to this home to calculate property tax. It is often lower than what the home would sell for.$1,414,672 (2026)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$707,336
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$707,336
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$1,386,934

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Duplex (2 Units, Any Combination)
StyleThe architectural style of the home, such as ranch or colonial.Duplex Single
CountySAN MATEO
Lot (acres)The size of the land the home sits on, from county records.0.14
FireplaceWhether the home has a fireplace, and what kind.Yes
GarageWhether the property has a garage, and details like whether it is attached to the home.Carport (Unspecified)
PoolWhether the property has a pool, and what kind, such as in-ground.No

Transaction History(5)

Sales and refinances filed with the county for this home. Not every transfer is a normal sale, so check the type before comparing prices.

Assigned SchoolsThe public schools this address is zoned for. Boundaries change, so confirm with the district before you count on it.

E
Sunnybrae Elementary SchoolD-
Elementary · Grades KG–5 · 0.4 mi
M
Borel Middle SchoolB
Middle · Grades 6–8 · 0.5 mi
H
Aragon High SchoolA
High · Grades 9–12 · 0.8 mi

District: San Mateo-Foster City Elementary School District

Neighborhood · ZIP 94402These are comparison scores, not percentages. 100 equals the national average, so 150 means about 50% above average.

CrimeLocal crime compared with the rest of the country, where 100 is average. It reflects things like population density, income, and how crime gets reported.91
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.88
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.595

Index scale: 100 = US average (tick). Lower is better.

Homes occupiedThe share of homes here that someone lives in. The rest sit empty, including vacation and for-sale homes.93%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.31%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.7.4%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.1%
PopulationHow many people live in this area.26,204
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.4,919 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$171,813
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$232,257
Average tempThe average temperature here across a full year.58°F
Annual precipHow much rain and melted snow falls here in a typical year.24 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.66%

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Data by ATTOM. Valuations are automated estimates, not appraisals. Photos from Google Street View and may not depict the current property state.

How this home compares

23 12th Ave measured against every home in its neighborhood, its ZIP code and its county, using county assessor records refreshed nightly. A home can stand out in one of those areas and look ordinary in another, because each one holds a different mix of homes.

  • Bigger than 76% of homes in Hayward Park
  • Older than 96% of homes in San Mateo County

How it measures up in San Mateo 94402

The dot is this home. The mark in the middle is the typical home in San Mateo 94402.

Living area2,104 ft²
SmallerTypical 1,920 ft²Bigger

Bigger than 60% of homes nearby

Lot size0.14 ac
SmallerTypical 0.16 acBigger

Bigger than 37% of homes nearby

Year built1924
OlderTypical 1950Newer

Newer than 7% of homes nearby

How 23 12th Ave ranks against every home in each area.
MeasureThis homeHayward ParkSan Mateo 94402San Mateo County
Living areabigger than2,104 ft²76% of homes60% of homes71% of homes
Lot sizebigger than0.14 ac40% of homes37% of homes46% of homes
Year builtnewer than192417% of homes7% of homes4% of homes

About 23 12th Ave

When did 23 12th Ave, San Mateo, CA last sell?

23 12th Ave, San Mateo, CA last sold on Dec 10, 2004 for $995,000, according to the county's recorded deed.

How big is 23 12th Ave, San Mateo, CA?

23 12th Ave, San Mateo, CA has 5 bedrooms, 2.5 bathrooms, 2,104 square feet of living space and a 0.14-acre lot.

When was 23 12th Ave, San Mateo, CA built?

23 12th Ave, San Mateo, CA was built in 1924, making it 102 years old. It is a duplex single home. The building has 2 stories.

What schools serve 23 12th Ave, San Mateo, CA?

23 12th Ave, San Mateo, CA is assigned to Sunnybrae Elementary School (elementary), rated D-; Borel Middle School (middle), rated B; Aragon High School (high), rated A. All sit in San Mateo-Foster City Elementary School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 23 12th Ave, San Mateo, CA compare to other homes in San Mateo 94402?

Among the 7,885 homes in San Mateo 94402, it is bigger than 60% of them (2,104 ft² against a typical 1,920 ft²), its lot is bigger than 37% of them (0.14 ac against a typical 0.16 ac) and it is newer than 7% of them (1924 against a typical 1950). These shares are recounted nightly from the full county assessor record for each area, not from active listings.

What are the property taxes on 23 12th Ave, San Mateo, CA?

The 2025 property tax bill for 23 12th Ave, San Mateo, CA was $19,699. The county assessed it at $1,414,672.

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Assigned schools

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