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Duplex (2 Units, Any Combination)Residential
Last sold for $200,000 on Oct 31, 1996

18 THOMAS ST

COS COB, CT 06807
5
Beds
3
Baths
2,538 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.
0.13 ac
Lot SizeThe size of the land the home sits on, from county records.
1948
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
10
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.

Valuation

Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$200,000 · Oct 31, 1996

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$8,090 (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.$654,570 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$423,080
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$231,490
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$654,570
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$458,199

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.51
48
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
8
WildfireProjected wildfire risk, scored 0 to 100, based on how much land burns in a typical year. Higher is riskier.
64
HeatProjected heat risk, scored 0 to 100, based on how many extremely hot days a year are expected. Higher is riskier.
96
StormProjected risk from heavy rainstorms, scored 0 to 100, based on how often extreme rainfall is expected. Higher is riskier.
43
DroughtProjected water shortage risk, scored 0 to 100. Higher means more strain on the local water supply.
Projected Flood DepthHow deep a serious flood is expected to get here at some point in the next 30 years. Shown in inches.13 in
30-Year Flood ChanceThe chance of at least one serious flood here in the next 30 years, not in any single year.30%
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.Duplex (2 Units, Any Combination)
StyleThe architectural style of the home, such as ranch or colonial.Duplex Single
CountyWESTERN CONNECTICUT
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.1960
Lot (acres)The size of the land the home sits on, from county records.0.13
ConstructionThe main material the home's frame and walls are built from.Frame (Unspecified)
RoofThe main material covering the roof, such as asphalt shingle or tile.Asphalt
HeatingThe type of heating system in the home.Hot Water
CoolingThe type of cooling or air conditioning in the home.Yes
FireplaceWhether the home has a fireplace, and what kind.Yes
PoolWhether the property has a pool, and what kind, such as in-ground.No
FeaturesExtra features found in county records. Records are not complete everywhere, so a missing feature does not always mean the home lacks it.Deck

Transaction History(6)

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
Cos Cob SchoolB
Elementary · Grades KG–5 · 0.5 mi
M
Central Middle SchoolA-
Middle · Grades 6–8 · 0.8 mi
H
Greenwich High SchoolA+
High · Grades 9–12 · 1.2 mi

District: Greenwich School District

Neighborhood · ZIP 06807These 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.54
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.112
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.103

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.94%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.34%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.6.3%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.0%
PopulationHow many people live in this area.7,630
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.2,321 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$180,144
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$235,340
Average tempThe average temperature here across a full year.52°F
Annual precipHow much rain and melted snow falls here in a typical year.51 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.58%

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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

18 Thomas 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.

  • Bigger than 66% of homes in Western Connecticut County
  • Has a smaller lot than 94% of homes in Cos Cob 06807
  • Older than 79% of homes in Western Connecticut County

How it measures up in Cos Cob 06807

The dot is this home. The mark in the middle is the typical home in Cos Cob 06807.

Living area2,538 ft²
SmallerTypical 2,388 ft²Bigger

Bigger than 56% of homes nearby

Lot size0.13 ac
SmallerTypical 0.29 acBigger

Bigger than 6% of homes nearby

Year built1948
OlderTypical 1964Newer

Newer than 30% of homes nearby

How 18 Thomas St ranks against every home in each area.
MeasureThis homeCos Cob 06807Western Connecticut County
Living areabigger than2,538 ft²56% of homes66% of homes
Lot sizebigger than0.13 ac6% of homes6% of homes
Year builtnewer than194830% of homes21% of homes

About 18 Thomas St

When did 18 Thomas St, Cos Cob, CT last sell?

18 Thomas St, Cos Cob, CT last sold on Oct 31, 1996 for $200,000, according to the county's recorded deed.

How big is 18 Thomas St, Cos Cob, CT?

18 Thomas St, Cos Cob, CT has 5 bedrooms, 3 bathrooms, 2,538 square feet of living space and a 0.13-acre lot.

When was 18 Thomas St, Cos Cob, CT built?

18 Thomas St, Cos Cob, CT was built in 1948, making it 78 years old. It is a duplex single home. The building has 2 stories.

What schools serve 18 Thomas St, Cos Cob, CT?

18 Thomas St, Cos Cob, CT is assigned to Cos Cob School (elementary), rated B; Central Middle School (middle), rated A-; Greenwich High School (high), rated A+. All sit in Greenwich School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 18 Thomas St, Cos Cob, CT compare to other homes in Cos Cob 06807?

Among the 2,396 homes in Cos Cob 06807, it is bigger than 56% of them (2,538 ft² against a typical 2,388 ft²), its lot is bigger than 6% of them (0.13 ac against a typical 0.29 ac) and it is newer than 30% of them (1948 against a typical 1964). These shares are recounted nightly from the full county assessor record for each area, not from active listings.

What are the property taxes on 18 Thomas St, Cos Cob, CT?

The 2025 property tax bill for 18 Thomas St, Cos Cob, CT was $8,090. The county assessed it at $654,570.

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