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Single Family ResidenceResidential
$3,530,521$1,058 / 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 94How 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
Last sold for $3,550,000 on Jun 12, 2024

528 WILLIAM ST

KEY WEST, FL 33040
3
Beds
3.5
Baths
3,338 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.
0.1 ac
Lot SizeThe size of the land the home sits on, from county records.
1933
Year BuiltThe year the home was originally built, according to county records.
4
StoriesHow many floors the home has above ground.

Valuation

$3.5M
$3.3M low$3.8M high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$3,550,000 · Jun 12, 2024

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$25,030 (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.$2,974,489 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$1,490,465
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$1,484,024
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$1,684,500
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$2,974,489

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.12 in
30-Year Flood ChanceThe chance of at least one serious flood here in the next 30 years, not in any single year.47%
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.minimal

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
CountyMONROE
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.2013
Lot (acres)The size of the land the home sits on, from county records.0.10
RoofThe main material covering the roof, such as asphalt shingle or tile.Metal
HeatingThe type of heating system in the home.Forced Air With Air Conditioning
CoolingThe type of cooling or air conditioning in the home.Yes
PoolWhether the property has a pool, and what kind, such as in-ground.Yes
FeaturesExtra features found in county records. Records are not complete everywhere, so a missing feature does not always mean the home lacks it.Patio · 378 ft²Porch · 526 ft²Water feature

Transaction History(10)

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.

M
Horace O'Bryant SchoolD+
Middle · Grades PK–8 · 0.8 mi
H
Key West High SchoolC-
High · Grades 9–12 · 1.4 mi
E
Gerald Adams Elementary SchoolC-
Elementary · Grades PK–5 · 3.7 mi

District: Monroe County School District

Neighborhood · ZIP 33040These 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.102
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 100.1

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.82%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.23%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.14%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.0.7%
PopulationHow many people live in this area.31,854
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.222 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$86,370
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$116,488
Average tempThe average temperature here across a full year.78°F
Annual precipHow much rain and melted snow falls here in a typical year.41 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.76%

Owner Tools

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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

528 William 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 more than 96% of homes in Key West 33040
  • Costs more per square foot than 77% of homes in Monroe County
  • Bigger than 97% of homes in Key West 33040
  • Has a smaller lot than 79% of homes in Monroe County
  • Older than 96% of homes in Monroe County

What homes are worth in Key West 33040

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

This home
$385K$4.4M

This home is worth more than 96% of homes in Key West 33040.

How it measures up in Key West 33040

The dot is this home. The mark in the middle is the typical home in Key West 33040.

Estimated value$3,530,521
CheaperTypical $991,649Pricier

Pricier than 96% of homes nearby

Price per ft²$1058
CheaperTypical $773Pricier

Pricier than 70% of homes nearby

Living area3,338 ft²
SmallerTypical 1,288 ft²Bigger

Bigger than 97% of homes nearby

Lot size0.1 ac
SmallerTypical 0.12 acBigger

Bigger than 39% of homes nearby

Year built1933
OlderTypical 1972Newer

Newer than 13% of homes nearby

How 528 William St ranks against every home in each area.
MeasureThis homeKey West 33040Monroe County
Estimated valuepricier than$3,530,52196% of homes93% of homes
Price per ft²pricier than$105870% of homes77% of homes
Living areabigger than3,338 ft²97% of homes95% of homes
Lot sizebigger than0.1 ac39% of homes21% of homes
Year builtnewer than193313% of homes4% of homes

About 528 William St

How much is 528 William St, Key West, FL worth?

The TopHap Estimate for 528 William St, Key West, FL is $3,530,521 as of Aug 30, 2026. The likely range is $3,310,420 to $3,750,622. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 528 William St, Key West, FL last sell?

528 William St, Key West, FL last sold on Jun 12, 2024 for $3,550,000, according to the county's recorded deed. TopHap holds 3 recorded sales for this parcel.

How big is 528 William St, Key West, FL?

528 William St, Key West, FL has 3 bedrooms, 3.5 bathrooms, 3,338 square feet of living space and a 0.10-acre lot.

When was 528 William St, Key West, FL built?

528 William St, Key West, FL was built in 1933, making it 93 years old. The building has 4 stories.

What schools serve 528 William St, Key West, FL?

528 William St, Key West, FL is assigned to Horace O'Bryant School (middle), rated D+; Key West High School (high), rated C-; Gerald Adams Elementary School (elementary), rated C-. All sit in Monroe County School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 528 William St, Key West, FL compare to other homes in Key West 33040?

Among the 11,959 homes in Key West 33040, it is worth more than 96% of them ($3,530,521 against a typical $991,649), its price per square foot is higher than 70% of them ($1058 against a typical $773), it is bigger than 97% of them (3,338 ft² against a typical 1,288 ft²), its lot is bigger than 39% of them (0.1 ac against a typical 0.12 ac) and it is newer than 13% of them (1933 against a typical 1972). Measured against all of Monroe County, it is worth more than 93% 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 528 William St, Key West, FL?

The 2025 property tax bill for 528 William St, Key West, FL was $25,030. The county assessed it at $2,974,489.

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