Triplex (3 Units, Any Combination)Residential
21 COTTAGE ST
DERBY, CT 06418
7
Beds
3
Baths
3,875 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.
0.28 ac
Lot SizeThe size of the land the home sits on, from county records.
1877
Year BuiltThe year the home was originally built, according to county records.
3
StoriesHow many floors the home has above ground.
14
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.
Tax & Assessment
Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$10,895 (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.$252,210 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$38,310
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$213,900
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$252,210
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$360,300
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.40
1
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
4
WildfireProjected wildfire risk, scored 0 to 100, based on how much land burns in a typical year. Higher is riskier.
61
HeatProjected heat risk, scored 0 to 100, based on how many extremely hot days a year are expected. Higher is riskier.
97
StormProjected risk from heavy rainstorms, scored 0 to 100, based on how often extreme rainfall is expected. Higher is riskier.
39
DroughtProjected water shortage risk, scored 0 to 100. Higher means more strain on the local water supply.
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.Triplex (3 Units, Any Combination)
CountyNAUGATUCK VALLEY
Lot (acres)The size of the land the home sits on, from county records.0.28
ConstructionThe main material the home's frame and walls are built from.Frame (Unspecified)
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
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.
EHM
Irving SchoolD-
Elementary · Grades KG–5 · 0.1 mi
Derby High SchoolD-
High · Grades 9–12 · 0.7 mi
Derby Middle SchoolD+
Middle · Grades 6–8 · 0.8 mi
District: Derby School District
Neighborhood · ZIP 06418These 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.109
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.113
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.69
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.16%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.15%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.0.9%
PopulationHow many people live in this area.12,707
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.2,336 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$63,431
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$87,707
Average tempThe average temperature here across a full year.51°F
Annual precipHow much rain and melted snow falls here in a typical year.50 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.58%
Owner Tools
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Claim this homeData 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 Cottage 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.
- Among the largest homes in Derby 06418
- Older than 98% of homes in Naugatuck Valley County
How it measures up in Derby 06418
The dot is this home. The mark in the middle is the typical home in Derby 06418.
Living area3,875 ft²
SmallerTypical 1,392 ft²Bigger
Bigger than almost all homes nearby
Lot size0.28 ac
SmallerTypical 0.25 acBigger
Bigger than 56% of homes nearby
Year built1877
OlderTypical 1959Newer
Newer than 6% of homes nearby
| Measure | This home | Derby 06418 | Naugatuck Valley County |
|---|---|---|---|
| Living areabigger than | 3,875 ft² | almost all homes | 98% of homes |
| Lot sizebigger than | 0.28 ac | 56% of homes | 37% of homes |
| Year builtnewer than | 1877 | 6% of homes | 2% of homes |
About 21 Cottage St
When did 21 Cottage St, Derby, CT last sell?
21 Cottage St, Derby, CT last sold on Jan 1, 1900, according to the county's recorded deed.
How big is 21 Cottage St, Derby, CT?
21 Cottage St, Derby, CT has 7 bedrooms, 3 bathrooms, 3,875 square feet of living space and a 0.28-acre lot.
When was 21 Cottage St, Derby, CT built?
21 Cottage St, Derby, CT was built in 1877, making it 149 years old. The building has 3 stories.
What schools serve 21 Cottage St, Derby, CT?
21 Cottage St, Derby, CT is assigned to Irving School (elementary), rated D-; Derby High School (high), rated D-; Derby Middle School (middle), rated D+. All sit in Derby School District. Attendance boundaries change — confirm with the district before relying on an assignment.
How does 21 Cottage St, Derby, CT compare to other homes in Derby 06418?
Among the 3,850 homes in Derby 06418, it is bigger than almost all of them (3,875 ft² against a typical 1,392 ft²), its lot is bigger than 56% of them (0.28 ac against a typical 0.25 ac) and it is newer than 6% of them (1877 against a typical 1959). 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 Cottage St, Derby, CT?
The 2025 property tax bill for 21 Cottage St, Derby, CT was $10,895. The county assessed it at $252,210.
More homes on Cottage St
- 10 Cottage St # 126 bd · 3 ba · 3,074 ft² · Sold $360K · Mar 2022
- 68 Cottage St4 bd · 3 ba · 4,344 ft² · Sold $315K · Feb 2022
- 68 Cottage St7 bd · 3 ba · 3,325 ft² · Sold $150K · Jan 2021
- 59 Cottage St$420K4 bd · 1.5 ba · 2,342 ft² · Sold $135K · May 2017
- 73 Cottage St7 bd · 3 ba · 3,416 ft² · Sold $135K · Sep 2015
- 14 Cottage St # 165 bd · 3 ba · 2,931 ft² · Sold $160K · Dec 2007
- 49 Cottage St4 bd · 2 ba · 1,792 ft² · Sold $270K · May 2006
- 79 Cottage St5 bd · 3 ba · 2,688 ft² · Sold $233K · May 2005
- 75 Cottage St5 bd · 2 ba · 1,845 ft² · Sold $145K · Apr 2003
- 18 Cottage St6 bd · 2 ba · 3,650 ft² · Sold $133K · Jul 1997
- 3 Cottage St7 bd · 2 ba · 2,886 ft² · Sold Jan 1900
- 15 Cottage St # 175 bd · 3 ba · 2,826 ft² · Sold Jan 1900
Closest homes
- 15 Cottage St77 ft · 5 bd · 3 ba · 2,826 ft² · Sold Jan 1900
- 277 Elizabeth St160 ft · 6 bd · 2.5 ba · 1,478 ft² · Sold $175K · May 2018
- 314 Caroline St139 ft · 4 bd · 2 ba · 2,316 ft² · Sold $94K · Jul 1994
- 79 Cottage St133 ft · 5 bd · 3 ba · 2,688 ft² · Sold $233K · May 2005
- 224 Minerva St179 ft · 5 bd · 2 ba · 2,343 ft² · Sold $335K · Jul 2007
- 322 Caroline St177 ft · 7 bd · 4 ba · 3,478 ft² · Sold $105K · Nov 2015
- 18 Cottage St198 ft · 6 bd · 2 ba · 3,650 ft² · Sold $133K · Jul 1997
- 283 Elizabeth St$396K209 ft · 3 bd · 2.5 ba · 1,679 ft² · Sold $35K · Aug 2003
More homes in Derby 06418
- 3 Coppola Ter$400K3 bd · 1 ba · 1,292 ft² · Sold $415K · Sep 2026
- 4 Oak St7 bd · 3.5 ba · 2,800 ft² · Sold $590K · Sep 2026
- 23 Washington St$600K2 bd · 1 ba · 1.73 ac · Sold $600K · Sep 2026
- 196 New Haven Ave$349K2 bd · 2.5 ba · 1,578 ft² · Sold $349K · Sep 2026
- 50 Orangewood W$316K3 bd · 2.5 ba · 1,280 ft² · Sold $330K · Sep 2026
- 171 Mount Pleasant St$339K3 bd · 1 ba · 1,115 ft² · Sold $337K · Sep 2026
- 50 Hawthorne Ave$324K3 bd · 2 ba · 1,692 ft² · Sold $375K · Sep 2026
- 232 Hawkins St3 bd · 2 ba · 1,888 ft² · Sold $371K · Sep 2026
- 105 Sunset Dr$400K2 bd · 1 ba · 957 ft² · Sold $400K · Sep 2026
- 44 Hawthorne Ave$209K2 bd · 1 ba · 1,240 ft² · Sold $98K · Sep 2026
- 22 Summit Cmns$322K2 bd · 1.5 ba · 1,102 ft² · Sold $320K · Sep 2026
- 118 Bradley Ter$295K2 bd · 1 ba · 841 ft² · Sold $147K · Sep 2026
Assigned schools
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