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Single Family ResidenceResidential
$1,218,641$1,071 / 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 90How 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

4121 COLBY ST

FREMONT, CA 94538
3
Beds
1.5
Baths
1,138 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.
0.12 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.
2
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.

Valuation

$1.2M
$1.1M low$1.3M high

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$3,092 (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.$201,008 (2026)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$110,841
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$97,167
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$196,930
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$959,490

Climate Risk

Projected Flood DepthHow deep a serious flood is expected to get here at some point in the next 30 years. Shown in inches.5 in
30-Year Flood ChanceThe chance of at least one serious flood here in the next 30 years, not in any single year.6%
FEMA Flood ZoneFEMA's flood zone for this address. Zones starting with A or V are high risk, and lenders usually require flood insurance there.0.2 percent flood zone

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
CountyALAMEDA
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.1957
Lot (acres)The size of the land the home sits on, from county records.0.12
ConstructionThe main material the home's frame and walls are built from.Wood (Unspecified)
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
Harvey Green Elementary SchoolA
Elementary · Grades KG–5 · 0.4 mi
H
Irvington High SchoolA+
High · Grades 9–12 · 0.9 mi
M
John M. Horner Middle SchoolA
Middle · Grades 6–8 · 1.1 mi

District: Fremont Unified School District

Neighborhood · ZIP 94538These 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.65
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.87
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.620

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.95%
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.5.3%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.6%
PopulationHow many people live in this area.67,745
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.2,952 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$137,410
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$160,880
Average tempThe average temperature here across a full year.59°F
Annual precipHow much rain and melted snow falls here in a typical year.16 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

4121 Colby St 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 69% of homes in Grimmer
  • Costs more per square foot than 94% of homes in Alameda County
  • Smaller than 79% of homes in Alameda County
  • Has a smaller lot than 81% of homes in Fremont 94538
  • Older than 92% of homes in Fremont 94538

What homes are worth in Fremont 94538

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

This home
$455K$1.9M

This home is worth more than 46% of homes in Fremont 94538.

How it measures up in Fremont 94538

The dot is this home. The mark in the middle is the typical home in Fremont 94538.

Estimated value$1,218,641
CheaperTypical $1,241,799Pricier

Pricier than 46% of homes nearby

Price per ft²$1071
CheaperTypical $867Pricier

Pricier than 88% of homes nearby

Living area1,138 ft²
SmallerTypical 1,380 ft²Bigger

Bigger than 23% of homes nearby

Lot size0.12 ac
SmallerTypical 0.14 acBigger

Bigger than 19% of homes nearby

Year built1955
OlderTypical 1963Newer

Newer than 8% of homes nearby

How 4121 Colby St ranks against every home in each area.
MeasureThis homeGrimmerFremont 94538Alameda County
Estimated valuepricier than$1,218,64131% of homes46% of homes61% of homes
Price per ft²pricier than$107175% of homes88% of homes94% of homes
Living areabigger than1,138 ft²26% of homes23% of homes21% of homes
Lot sizebigger than0.12 ac32% of homes19% of homes37% of homes
Year builtnewer than195514% of homes8% of homes39% of homes

About 4121 Colby St

How much is 4121 Colby St, Fremont, CA worth?

The TopHap Estimate for 4121 Colby St, Fremont, CA is $1,218,641 as of Aug 30, 2026. The likely range is $1,093,721 to $1,343,561. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 4121 Colby St, Fremont, CA last sell?

4121 Colby St, Fremont, CA last sold on Jan 1, 1900, according to the county's recorded deed. TopHap holds 2 recorded sales for this parcel.

How big is 4121 Colby St, Fremont, CA?

4121 Colby St, Fremont, CA has 3 bedrooms, 1.5 bathrooms, 1,138 square feet of living space and a 0.12-acre lot.

When was 4121 Colby St, Fremont, CA built?

4121 Colby St, Fremont, CA was built in 1955, making it 71 years old. The building has 2 stories.

What schools serve 4121 Colby St, Fremont, CA?

4121 Colby St, Fremont, CA is assigned to Harvey Green Elementary School (elementary), rated A; Irvington High School (high), rated A+; John M. Horner Middle School (middle), rated A. All sit in Fremont Unified School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 4121 Colby St, Fremont, CA compare to other homes in Fremont 94538?

Among the 15,977 homes in Fremont 94538, it is worth more than 46% of them ($1,218,641 against a typical $1,241,799), its price per square foot is higher than 88% of them ($1071 against a typical $867), it is bigger than 23% of them (1,138 ft² against a typical 1,380 ft²), its lot is bigger than 19% of them (0.12 ac against a typical 0.14 ac) and it is newer than 8% of them (1955 against a typical 1963). Measured against all of Alameda County, it is worth more than 61% 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 4121 Colby St, Fremont, CA?

The 2025 property tax bill for 4121 Colby St, Fremont, CA was $3,092. The county assessed it at $201,008.

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