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Single Family ResidenceResidential
$2,006,471$830 / 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 Aug 30, 2026

280 SOUTH AVE

ALAMO, CA 94507
4
Beds
3
Baths
2,418 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.
0.57 ac
Lot SizeThe size of the land the home sits on, from county records.
1955
Year BuiltThe year the home was originally built, according to county records.
1
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

$2M
$1.7M low$2.3M high

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$5,567 (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.$446,173 (2026)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$135,877
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$310,296
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$437,425

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.37
1
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
83
WildfireProjected wildfire risk, scored 0 to 100, based on how much land burns in a typical year. Higher is riskier.
39
HeatProjected heat risk, scored 0 to 100, based on how many extremely hot days a year are expected. Higher is riskier.
51
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.1970
Lot (acres)The size of the land the home sits on, from county records.0.57
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.Yes

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
Rancho Romero Elementary SchoolA
Elementary · Grades KG–5 · 0.4 mi
M
Stone Valley Middle SchoolA+
Middle · Grades 6–8 · 1.3 mi
H
San Ramon High SchoolA+
High · Grades 9–12 · 1.9 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

280 South 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.

  • Worth more than 91% of homes in Contra Costa County
  • Costs more per square foot than 94% of homes in Contra Costa County
  • Smaller than 79% of homes in Alamo 94507
  • Has a bigger lot than 94% of homes in Contra Costa County
  • Older than 86% 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$5M

This home is worth more than 23% 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$2,006,471
CheaperTypical $2,450,471Pricier

Pricier than 23% of homes nearby

Price per ft²$830
CheaperTypical $784Pricier

Pricier than 65% of homes nearby

Living area2,418 ft²
SmallerTypical 3,110 ft²Bigger

Bigger than 21% of homes nearby

Lot size0.57 ac
SmallerTypical 0.51 acBigger

Bigger than 63% of homes nearby

Year built1955
OlderTypical 1977Newer

Newer than 14% of homes nearby

How 280 South Ave ranks against every home in each area.
MeasureThis homeAlamo 94507Contra Costa County
Estimated valuepricier than$2,006,47123% of homes91% of homes
Price per ft²pricier than$83065% of homes94% of homes
Living areabigger than2,418 ft²21% of homes76% of homes
Lot sizebigger than0.57 ac63% of homes94% of homes
Year builtnewer than195514% of homes21% of homes

About 280 South Ave

How much is 280 South Ave, Alamo, CA worth?

The TopHap Estimate for 280 South Ave, Alamo, CA is $2,006,471 as of Aug 30, 2026. The likely range is $1,689,906 to $2,323,036. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 280 South Ave, Alamo, CA last sell?

280 South Ave, Alamo, CA last sold on Jan 1, 1900, according to the county's recorded deed.

How big is 280 South Ave, Alamo, CA?

280 South Ave, Alamo, CA has 4 bedrooms, 3 bathrooms, 2,418 square feet of living space and a 0.57-acre lot.

When was 280 South Ave, Alamo, CA built?

280 South Ave, Alamo, CA was built in 1955, making it 71 years old. The building has 1 story.

What schools serve 280 South Ave, Alamo, CA?

280 South Ave, 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 280 South Ave, Alamo, CA compare to other homes in Alamo 94507?

Among the 5,469 homes in Alamo 94507, it is worth more than 23% of them ($2,006,471 against a typical $2,450,471), its price per square foot is higher than 65% of them ($830 against a typical $784), it is bigger than 21% of them (2,418 ft² against a typical 3,110 ft²), its lot is bigger than 63% of them (0.57 ac against a typical 0.51 ac) and it is newer than 14% of them (1955 against a typical 1977). Measured against all of Contra Costa County, it is worth more than 91% 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 280 South Ave, Alamo, CA?

The 2025 property tax bill for 280 South Ave, Alamo, CA was $5,567. The county assessed it at $446,173.

More homes on South Ave

Closest homes

More homes in Alamo 94507

Assigned schools

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