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Single Family ResidenceResidential
$531,733$382 / 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 Oct 21, 2026

21 HARMON ST

MATTAPAN, MA 02126
3
Beds
1.5
Baths
1,392 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.
4,000 ft²
Lot SizeThe size of the land the home sits on, from county records.
1960
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
6
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

$532K
$502K low$562K high

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$5,870 (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.$506,900 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$157,600
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$349,300
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$583,585

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Single Family Residence
StyleThe architectural style of the home, such as ranch or colonial.Colonial
CountySUFFOLK
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.1989
Lot (acres)The size of the land the home sits on, from county records.0.09
RoofThe main material covering the roof, such as asphalt shingle or tile.Asphalt
HeatingThe type of heating system in the home.Hot Water
PoolWhether the property has a pool, and what kind, such as in-ground.No

Transaction History(1)

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
James J Chittick Elementary SchoolD
Elementary · Grades PK–5 · 0.2 mi
M
Mildred Avenue K-8 SchoolF
Middle · Grades KG–8 · 0.7 mi
H
Another Course To CollegeD-
High · Grades 9–12 · 0.8 mi

District: Boston School District

Neighborhood · ZIP 02126These 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.84
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.100
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.75

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.16%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.18%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.2%
PopulationHow many people live in this area.22,143
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.12,185 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$74,782
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$107,132
Average tempThe average temperature here across a full year.50°F
Annual precipHow much rain and melted snow falls here in a typical year.48 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

21 Harmon 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 78% of homes in Suffolk County
  • Costs less per square foot than 89% of homes in Suffolk County
  • Smaller than 73% of homes in Mattapan 02126
  • Has a smaller lot than 78% of homes in Mattapan 02126
  • Newer than 87% of homes in Mattapan

What homes are worth in Mattapan 02126

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

This home
$281K$787K

This home is worth more than 41% of homes in Mattapan 02126.

How it measures up in Mattapan 02126

The dot is this home. The mark in the middle is the typical home in Mattapan 02126.

Estimated value$531,733
CheaperTypical $550,356Pricier

Pricier than 41% of homes nearby

Price per ft²$382
CheaperTypical $397Pricier

Pricier than 41% of homes nearby

Living area1,392 ft²
SmallerTypical 1,925 ft²Bigger

Bigger than 27% of homes nearby

Lot size4,000 ft²
SmallerTypical 0.11 acBigger

Bigger than 22% of homes nearby

Year built1960
OlderTypical 1930Newer

Newer than 86% of homes nearby

How 21 Harmon St ranks against every home in each area.
MeasureThis homeMattapanMattapan 02126Suffolk County
Estimated valuepricier than$531,73338% of homes41% of homes22% of homes
Price per ft²pricier than$38236% of homes41% of homes11% of homes
Living areabigger than1,392 ft²30% of homes27% of homes47% of homes
Lot sizebigger than4,000 ft²25% of homes22% of homes62% of homes
Year builtnewer than196087% of homes86% of homes74% of homes

About 21 Harmon St

How much is 21 Harmon St, Mattapan, MA worth?

The TopHap Estimate for 21 Harmon St, Mattapan, MA is $531,733 as of Oct 21, 2026. The likely range is $501,735 to $561,731. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 21 Harmon St, Mattapan, MA last sell?

21 Harmon St, Mattapan, MA last sold on Jan 1, 1900, according to the county's recorded deed.

How big is 21 Harmon St, Mattapan, MA?

21 Harmon St, Mattapan, MA has 3 bedrooms, 1.5 bathrooms, 1,392 square feet of living space and a 0.09-acre lot.

When was 21 Harmon St, Mattapan, MA built?

21 Harmon St, Mattapan, MA was built in 1960, making it 66 years old. It is a colonial home. The building has 2 stories.

What schools serve 21 Harmon St, Mattapan, MA?

21 Harmon St, Mattapan, MA is assigned to James J Chittick Elementary School (elementary), rated D; Mildred Avenue K-8 School (middle), rated F; Another Course To College (high), rated D-. All sit in Boston School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 21 Harmon St, Mattapan, MA compare to other homes in Mattapan 02126?

Among the 3,890 homes in Mattapan 02126, it is worth more than 41% of them ($531,733 against a typical $550,356), its price per square foot is higher than 41% of them ($382 against a typical $397), it is bigger than 27% of them (1,392 ft² against a typical 1,925 ft²), its lot is bigger than 22% of them (4,000 ft² against a typical 0.11 ac) and it is newer than 86% of them (1960 against a typical 1930). Measured against all of Suffolk County, it is worth more than 22% 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 21 Harmon St, Mattapan, MA?

The 2025 property tax bill for 21 Harmon St, Mattapan, MA was $5,870. The county assessed it at $506,900.

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