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CondominiumResidential

21 Hartwell St

WALTHAM, MA 02453
0.21 ac
Lot SizeThe size of the land the home sits on, from county records.
1900
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
Built 19004 units1,743–1,931 ft²
$1.8M
All units combinedThe sum of our current value estimates for every unit in the building — roughly what the whole building's homes are worth together.
$611K
Median unit valueThe middle unit value in this building by our estimate: half the units are worth more, half less.
$335
Median $/ft²The middle price per square foot across the building's units, by our current estimates. Useful for comparing units of different sizes.

-29.3%vs the Waltham ZIP median sale $/ft² ($474)

Sales Performance

$550K
Median sale (12 mo)The middle sale price among this building's units that sold in the last 12 months, from recorded deeds.
—
1-yr changeHow the building's median sale price over the last 12 months compares with the 12 months before that.
1
Sales (12 mo)Units in this building that sold in the last 12 months, from recorded arms-length deeds.
25.0%
Turnover (12 mo)The share of units that changed hands in the last 12 months. Around 4–6% a year is typical; much higher can signal investor churn or a wave of exits.
This building's own appreciationThe building's own appreciation: for every unit that sold twice (held over a year), we compute its yearly price change between the two sales and take the middle value. This is the cleanest read on how this specific building performs, because it compares each unit to itself.
+4.7%per yeartypical hold 9.2 yrsfrom 5 same-unit resales
Median sale price (yearly, all time)Every recorded arms-length sale in the building since records begin, grouped by year: the bars count sales and the line tracks the median price paid.MedianSales
201020122021202220242025
Sale price per ft² (yearly, all time)The middle price per square foot across the building's units, by our current estimates. Useful for comparing units of different sizes.$/ft²
201020122021202220242025

9 arms-length sales on record for this building.

Unit Mix & Floor PlansThe building's recurring floor plans, found by grouping units with identical beds, baths and square footage in county records. Larger groups are the building's standard layouts; leftover units have one-off sizes.

2 bed
2 units
3 bed
2 units

Value DistributionHow the building's units spread across value ranges by our current estimates. A wide spread usually means big differences in size, floor or view.

$557K–$557K
1 unit
$611K–$611K
1 unit
$621K–$621K
1 unit

Ownership & Financing

Owner-occupiedThe share of units where the owner lives in the unit, per county records. The rest are second homes or rentals.75%
Company-ownedUnits owned through an LLC, trust, or other company — a rough proxy for investor ownership.25%
Typical owner tenureThe middle number of years since each unit last changed hands — how long the current owners have been in place.3.6 yrs
Cash purchases (5 yrs)The share of purchases in the last 5 years with no mortgage recorded. High cash share is common in second-home and investor buildings.33%
Avg. loan-to-valueAverage current loan balance against unit value across the building. Low numbers mean owners hold lots of equity — a sign of financial stability.55%
Median owner equityThe middle dollar amount of equity (value minus loans) unit owners hold in this building.$649,671
Median tax billThe middle annual property tax bill among the building's units.$5,472
Pre-foreclosure noticesUnits with an active pre-foreclosure or foreclosure notice on file.0

Recent SalesThe latest recorded arms-length sales in the building, newest first.

Unit 1Nov 25, 2025$550,000Unit 4Aug 6, 2024$615,000Unit 4Aug 4, 2022$545,000Unit 3Jul 21, 2021$580,000Unit 3Apr 30, 2012$349,000Unit 1Jul 19, 2010$363,000Unit 3Jun 16, 2010$364,500Unit 4Jun 1, 2010$311,000Unit 2May 28, 2010$316,000

Values are TopHap estimates, not appraisals. Sales, ownership and tax figures come from recorded county documents via ATTOM and can lag by several weeks.

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Condominium
CountyMIDDLESEX
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.Steam
PoolWhether the property has a pool, and what kind, such as in-ground.No

Assigned SchoolsThe public schools this address is zoned for. Boundaries change, so confirm with the district before you count on it.

E
William F. Stanley Elementary SchoolB-
Elementary · Grades KG–5 · 0.7 mi
M
John W. McDevitt Middle SchoolB
Middle · Grades 6–8 · 1.9 mi
H
Waltham Sr High SchoolC
High · Grades 9–12 · 2.8 mi

District: Waltham School District

Neighborhood · ZIP 02453These 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.106
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.104
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.73

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.31%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.6.8%
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.32,080
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.8,464 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$106,981
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$136,606
Average tempThe average temperature here across a full year.49°F
Annual precipHow much rain and melted snow falls here in a typical year.47 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.58%

All UnitsEvery property record the county has at this street address, such as the units in a condo building. Prices shown are our estimates, not asking prices.

21 Hartwell St
2 bd · 1.5 ba · 1,828 ft²
$557K
21 Hartwell St
2 bd · 1.5 ba · 1,824 ft²
$611K
21 Hartwell St # 3
3 bd · 1.5 ba · 1,931 ft²
21 Hartwell St # 4
3 bd · 1.5 ba · 1,743 ft²
$621K

Data by ATTOM. Valuations are automated estimates, not appraisals. Photos from Google Street View and may not depict the current property state.

About 21 Hartwell St

How many units are in 21 Hartwell St, Waltham, MA?

21 Hartwell St, Waltham, MA has 4 residential units across built in 1900, according to county assessor records.

What is a unit at 21 Hartwell St, Waltham, MA worth?

The median TopHap Estimate across the 4 units at 21 Hartwell St, Waltham, MA is $610,923. That works out to $335 per square foot. Units run from 1,743 to 1,931 square feet. Estimates are modelled from recorded sales and assessments, not appraisals.

Is 21 Hartwell St, Waltham, MA expensive for Waltham?

Units at 21 Hartwell St, Waltham, MA carry a median of $335 per square foot, 29% below the Waltham median of $474 per square foot.

How often do units sell at 21 Hartwell St, Waltham, MA?

1 units at 21 Hartwell St, Waltham, MA sold in the last 12 months, out of 9 recorded arms-length sales all time. That is a turnover rate of 25.0% of the building per year. The median sale over that period was $550K.

Have units at 21 Hartwell St, Waltham, MA appreciated?

Across 5 repeat sales of the same unit, 21 Hartwell St, Waltham, MA returned a median 4.7% per year. Because each pair is the same unit bought and sold, the figure is not distorted by which units traded. The median owner held for 9.2 years.

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Assigned schools

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