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Single Family ResidenceResidential
$1,325,152$1,013 / ft²
TopHap EstimateOur estimate of what this home would sell for today, based on nearby sales, the home's size and features, and local price trends. It is a starting point, not an appraisal.· confidence 84How well the pricing models agreed with each other on this home. Higher means the estimate rests on stronger, more consistent data.· as of Sep 24, 2026
Last sold for $370,000 on Aug 25, 1997

21 LA SONOMA DR

ALAMO, CA 94507
3
Beds
2
Baths
1,308 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.
0.5 ac
Lot SizeThe size of the land the home sits on, from county records.
1951
Year BuiltThe year the home was originally built, according to county records.
1
StoriesHow many floors the home has above ground.
5
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

$1.3M
$1.1M low$1.5M high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$370,000 · Aug 25, 1997

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$7,371 (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.$602,589 (2026)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$423,448
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$179,141
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$590,775

Climate Risk

Overall riskThe average of the five hazard scores below, on a 0 to 100 scale. Higher means greater projected risk over the coming decades.38
1
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
85
WildfireProjected wildfire risk, scored 0 to 100, based on how much land burns in a typical year. Higher is riskier.
43
HeatProjected heat risk, scored 0 to 100, based on how many extremely hot days a year are expected. Higher is riskier.
49
StormProjected risk from heavy rainstorms, scored 0 to 100, based on how often extreme rainfall is expected. Higher is riskier.
14
DroughtProjected water shortage risk, scored 0 to 100. Higher means more strain on the local water supply.

Scores 0–100; higher = greater projected risk.

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Single Family Residence
CountyCONTRA COSTA
Effective Year BuiltAn adjusted build year that accounts for condition and major remodels. A big renovation can make a home count as newer than it is.1965
Lot (acres)The size of the land the home sits on, from county records.0.50
GarageWhether the property has a garage, and details like whether it is attached to the home.Garage, Attached
PoolWhether the property has a pool, and what kind, such as in-ground.No

Transaction History(4)

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
Rancho Romero Elementary SchoolA+
Elementary · Grades KG–5 · 0.2 mi
M
Stone Valley Middle SchoolA
Middle · Grades 6–8 · 1.4 mi
H
San Ramon High SchoolA
High · Grades 9–12 · 1.5 mi

District: San Ramon Valley Unified School District

Neighborhood · ZIP 94507These 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.48
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 100.567

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.97%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.44%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.3.8%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.3%
PopulationHow many people live in this area.13,817
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.1,241 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$216,734
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$278,668
Average tempThe average temperature here across a full year.58°F
Annual precipHow much rain and melted snow falls here in a typical year.23 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.78%

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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

21 La Sonoma Dr 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.

  • Worth less than 95% of homes in Alamo 94507
  • Among the highest price per square foot in Contra Costa County
  • Smaller than 98% of homes in Alamo 94507
  • Has a bigger lot than 92% of homes in Contra Costa County
  • Older than 91% of homes in Alamo 94507

What homes are worth in Alamo 94507

Each bar is how many homes fall in that price range. The marker is this home.

This home
$1.1M$4.9M

This home is worth more than 5% of homes in Alamo 94507.

How it measures up in Alamo 94507

The dot is this home. The mark in the middle is the typical home in Alamo 94507.

Estimated value$1,325,152
CheaperTypical $2,434,594Pricier

Pricier than 5% of homes nearby

Price per ft²$1013
CheaperTypical $782Pricier

Pricier than 95% of homes nearby

Living area1,308 ft²
SmallerTypical 3,111 ft²Bigger

Bigger than 2% of homes nearby

Lot size0.5 ac
SmallerTypical 0.51 acBigger

Bigger than 45% of homes nearby

Year built1951
OlderTypical 1977Newer

Newer than 9% of homes nearby

How 21 La Sonoma Dr ranks against every home in each area.
MeasureThis homeAlamo 94507Contra Costa County
Estimated valuepricier than$1,325,1525% of homes78% of homes
Price per ft²pricier than$101395% of homesalmost all homes
Living areabigger than1,308 ft²2% of homes26% of homes
Lot sizebigger than0.5 ac45% of homes92% of homes
Year builtnewer than19519% of homes15% of homes

About 21 La Sonoma Dr

How much is 21 La Sonoma Dr, Alamo, CA worth?

The TopHap Estimate for 21 La Sonoma Dr, Alamo, CA is $1,325,152 as of Sep 24, 2026. The likely range is $1,113,158 to $1,537,146. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 21 La Sonoma Dr, Alamo, CA last sell?

21 La Sonoma Dr, Alamo, CA last sold on Aug 25, 1997 for $370,000, according to the county's recorded deed.

How big is 21 La Sonoma Dr, Alamo, CA?

21 La Sonoma Dr, Alamo, CA has 3 bedrooms, 2 bathrooms, 1,308 square feet of living space and a 0.50-acre lot.

When was 21 La Sonoma Dr, Alamo, CA built?

21 La Sonoma Dr, Alamo, CA was built in 1951, making it 75 years old. The building has 1 story.

What schools serve 21 La Sonoma Dr, Alamo, CA?

21 La Sonoma Dr, Alamo, CA is assigned to Rancho Romero Elementary School (elementary), rated A+; Stone Valley Middle School (middle), rated A; San Ramon High School (high), rated A. All sit in San Ramon Valley Unified School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 21 La Sonoma Dr, Alamo, CA compare to other homes in Alamo 94507?

Among the 5,469 homes in Alamo 94507, it is worth more than 5% of them ($1,325,152 against a typical $2,434,594), its price per square foot is higher than 95% of them ($1013 against a typical $782), it is bigger than 2% of them (1,308 ft² against a typical 3,111 ft²), its lot is bigger than 45% of them (0.5 ac against a typical 0.51 ac) and it is newer than 9% of them (1951 against a typical 1977). Measured against all of Contra Costa County, it is worth more than 78% of homes there. These shares are recounted nightly from the full county assessor record for each area, not from active listings.

What are the property taxes on 21 La Sonoma Dr, Alamo, CA?

The 2025 property tax bill for 21 La Sonoma Dr, Alamo, CA was $7,371. The county assessed it at $602,589.

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