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Single Family ResidenceResidential
$1,292,712$454 / 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 89How well the pricing models agreed with each other on this home. Higher means the estimate rests on stronger, more consistent data.· as of Sep 24, 2026
Last sold for $1,284,000 on Jul 30, 2026

21 WILLIAM ST

ANDOVER, MA 01810
5
Beds
2.5
Baths
2,846 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.
1920
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

$1.3M
$1.2M low$1.4M high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$1,284,000 · Jul 30, 2026

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$14,976 (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.$1,199,000 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$528,800
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$670,200
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$1,084,100
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$1,397,640

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
CountyESSEX
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)
RoofThe main material covering the roof, such as asphalt shingle or tile.Slate
HeatingThe type of heating system in the home.Steam
FireplaceWhether the home has a fireplace, and what kind.Yes
GarageWhether the property has a garage, and details like whether it is attached to the home.Garage, Detached
PoolWhether the property has a pool, and what kind, such as in-ground.No

Transaction History(11)

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
West Elementary SchoolA-
Elementary · Grades KG–5 · 1.1 mi
M
West Middle SchoolA+
Middle · Grades 6–8 · 1.1 mi
H
Andover High SchoolA
High · Grades 9–12 · 1.2 mi

District: Andover School District

Neighborhood · ZIP 01810These 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.41
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.99
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.90

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.96%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.35%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.3.0%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.4%
PopulationHow many people live in this area.37,155
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.1,160 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$155,617
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$207,356
Average tempThe average temperature here across a full year.48°F
Annual precipHow much rain and melted snow falls here in a typical year.46 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 William 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 more than 91% of homes in Essex County
  • Costs more per square foot than 77% of homes in Andover 01810
  • Bigger than 81% of homes in Essex County
  • Has a smaller lot than 88% of homes in Andover 01810
  • Older than 87% of homes in Andover 01810

What homes are worth in Andover 01810

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

This home
$293K$2.3M

This home is worth more than 77% of homes in Andover 01810.

How it measures up in Andover 01810

The dot is this home. The mark in the middle is the typical home in Andover 01810.

Estimated value$1,292,712
CheaperTypical $973,013Pricier

Pricier than 77% of homes nearby

Price per ft²$454
CheaperTypical $401Pricier

Pricier than 77% of homes nearby

Living area2,846 ft²
SmallerTypical 2,451 ft²Bigger

Bigger than 61% of homes nearby

Lot size0.28 ac
SmallerTypical 0.77 acBigger

Bigger than 12% of homes nearby

Year built1920
OlderTypical 1969Newer

Newer than 13% of homes nearby

How 21 William St ranks against every home in each area.
MeasureThis homeAndover 01810Essex County
Estimated valuepricier than$1,292,71277% of homes91% of homes
Price per ft²pricier than$45477% of homes67% of homes
Living areabigger than2,846 ft²61% of homes81% of homes
Lot sizebigger than0.28 ac12% of homes52% of homes
Year builtnewer than192013% of homes30% of homes

About 21 William St

How much is 21 William St, Andover, MA worth?

The TopHap Estimate for 21 William St, Andover, MA is $1,292,712 as of Sep 24, 2026. The likely range is $1,153,061 to $1,432,363. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 21 William St, Andover, MA last sell?

21 William St, Andover, MA last sold on Jul 30, 2026 for $1,284,000, according to the county's recorded deed.

How big is 21 William St, Andover, MA?

21 William St, Andover, MA has 5 bedrooms, 2.5 bathrooms, 2,846 square feet of living space and a 0.28-acre lot.

When was 21 William St, Andover, MA built?

21 William St, Andover, MA was built in 1920, making it 106 years old. It is a colonial home. The building has 2 stories.

What schools serve 21 William St, Andover, MA?

21 William St, Andover, MA is assigned to West Elementary School (elementary), rated A-; West Middle School (middle), rated A+; Andover High School (high), rated A. All sit in Andover School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 21 William St, Andover, MA compare to other homes in Andover 01810?

Among the 11,074 homes in Andover 01810, it is worth more than 77% of them ($1,292,712 against a typical $973,013), its price per square foot is higher than 77% of them ($454 against a typical $401), it is bigger than 61% of them (2,846 ft² against a typical 2,451 ft²), its lot is bigger than 12% of them (0.28 ac against a typical 0.77 ac) and it is newer than 13% of them (1920 against a typical 1969). Measured against all of Essex County, it is worth more than 91% 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 William St, Andover, MA?

The 2025 property tax bill for 21 William St, Andover, MA was $14,976. The county assessed it at $1,199,000.

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