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Single Family ResidenceResidential
$899,538$469 / 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 95How well the pricing models agreed with each other on this home. Higher means the estimate rests on stronger, more consistent data.· as of Jul 14, 2026

21 DEMEREST ST

WALTHAM, MA 02452
4
Beds
1.5
Baths
1,918 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.
0.17 ac
Lot SizeThe size of the land the home sits on, from county records.
1971
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
7
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.

Valuation

$900K
$852K low$947K high

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$7,275 (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.$740,800 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$432,900
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$307,900
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$938,220

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.10 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.Single Family Residence
StyleThe architectural style of the home, such as ranch or colonial.Colonial
CountyMIDDLESEX
Lot (acres)The size of the land the home sits on, from county records.0.17
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

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
Northeast Elementary SchoolC+
Elementary · Grades KG–5 · 1.2 mi
H
Waltham Sr High SchoolC
High · Grades 9–12 · 1.5 mi
M
John F. Kennedy Middle SchoolA-
Middle · Grades 6–8 · 1.6 mi

District: Waltham School District

Neighborhood · ZIP 02452These 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.93
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.105
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.77

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.31%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.10.0%
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.17,230
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.4,328 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$97,289
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$131,986
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%

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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 Demerest 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.

  • Has a smaller lot than 79% of homes in Waltham 02452
  • Newer than 65% of homes in Middlesex County

What homes are worth in Waltham 02452

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

This home
$377K$1.9M

This home is worth more than 54% of homes in Waltham 02452.

How it measures up in Waltham 02452

The dot is this home. The mark in the middle is the typical home in Waltham 02452.

Estimated value$899,538
CheaperTypical $878,502Pricier

Pricier than 54% of homes nearby

Price per ft²$469
CheaperTypical $481Pricier

Pricier than 46% of homes nearby

Living area1,918 ft²
SmallerTypical 1,900 ft²Bigger

Bigger than 51% of homes nearby

Lot size0.17 ac
SmallerTypical 0.34 acBigger

Bigger than 21% of homes nearby

Year built1971
OlderTypical 1977Newer

Newer than 46% of homes nearby

How 21 Demerest St ranks against every home in each area.
MeasureThis homeWaltham 02452Middlesex County
Estimated valuepricier than$899,53854% of homes62% of homes
Price per ft²pricier than$46946% of homes52% of homes
Living areabigger than1,918 ft²51% of homes53% of homes
Lot sizebigger than0.17 ac21% of homes30% of homes
Year builtnewer than197146% of homes65% of homes

About 21 Demerest St

How much is 21 Demerest St, Waltham, MA worth?

The TopHap Estimate for 21 Demerest St, Waltham, MA is $899,538 as of Jul 14, 2026. The likely range is $852,489 to $946,587. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 21 Demerest St, Waltham, MA last sell?

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

How big is 21 Demerest St, Waltham, MA?

21 Demerest St, Waltham, MA has 4 bedrooms, 1.5 bathrooms, 1,918 square feet of living space and a 0.17-acre lot.

When was 21 Demerest St, Waltham, MA built?

21 Demerest St, Waltham, MA was built in 1971, making it 55 years old. It is a colonial home. The building has 2 stories.

What schools serve 21 Demerest St, Waltham, MA?

21 Demerest St, Waltham, MA is assigned to Northeast Elementary School (elementary), rated C+; Waltham Sr High School (high), rated C; John F. Kennedy Middle School (middle), rated A-. All sit in Waltham School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 21 Demerest St, Waltham, MA compare to other homes in Waltham 02452?

Among the 3,442 homes in Waltham 02452, it is worth more than 54% of them ($899,538 against a typical $878,502), its price per square foot is higher than 46% of them ($469 against a typical $481), it is bigger than 51% of them (1,918 ft² against a typical 1,900 ft²), its lot is bigger than 21% of them (0.17 ac against a typical 0.34 ac) and it is newer than 46% of them (1971 against a typical 1977). Measured against all of Middlesex County, it is worth more than 62% 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 Demerest St, Waltham, MA?

The 2025 property tax bill for 21 Demerest St, Waltham, MA was $7,275. The county assessed it at $740,800.

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