Skip to content
Skip to content
TopHapOpen in map
CondominiumResidential
$1,186,708$517 / 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 90How 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
Last sold for $920,000 on Sep 30, 2020

20 PORTER ST

WATERTOWN, MA 02472
4
Beds
3
Baths
2,296 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.
0.12 ac
Lot SizeThe size of the land the home sits on, from county records.
1909
Year BuiltThe year the home was originally built, according to county records.
3
StoriesHow many floors the home has above ground.
8
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.

Valuation

$1.2M
$1.1M low$1.3M high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$920,000 · Sep 30, 2020

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$11,600 (2026)
Assessed ValueThe value the county assigns to this home to calculate property tax. It is often lower than what the home would sell for.$950,800 (2026)
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$950,800
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$1,039,585

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.35
1
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
1
WildfireProjected wildfire risk, scored 0 to 100, based on how much land burns in a typical year. Higher is riskier.
58
HeatProjected heat risk, scored 0 to 100, based on how many extremely hot days a year are expected. Higher is riskier.
84
StormProjected risk from heavy rainstorms, scored 0 to 100, based on how often extreme rainfall is expected. Higher is riskier.
32
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.Condominium
StyleThe architectural style of the home, such as ranch or colonial.Condo/Apartment
CountyMIDDLESEX
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.2020
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.Forced Air With Air Conditioning
CoolingThe type of cooling or air conditioning in the home.Yes
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
Hosmer Elementary SchoolB
Elementary · Grades PK–5 · 0.3 mi
H
Watertown High SchoolC+
High · Grades 9–12 · 0.7 mi
M
Watertown Middle SchoolB-
Middle · Grades 6–8 · 1.4 mi

District: Watertown School District

Neighborhood · ZIP 02472These 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.112
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.103
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.71

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.34%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.6.6%
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.35,928
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.8,689 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$115,227
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$149,103
Average tempThe average temperature here across a full year.50°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%

Owner Tools

Do you own this home?
Claim this home

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

20 Porter 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 87% of homes in Watertown 02472
  • Costs less per square foot than 73% of homes in East Watertown
  • Bigger than 68% of homes in Watertown 02472
  • Has a smaller lot than 82% of homes in Middlesex County
  • Older than 84% of homes in Watertown 02472

What homes are worth in Watertown 02472

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

This home
$372K$1.8M

This home is worth more than 87% of homes in Watertown 02472.

How it measures up in Watertown 02472

The dot is this home. The mark in the middle is the typical home in Watertown 02472.

Estimated value$1,186,708
CheaperTypical $811,593Pricier

Pricier than 87% of homes nearby

Price per ft²$517
CheaperTypical $584Pricier

Pricier than 27% of homes nearby

Living area2,296 ft²
SmallerTypical 1,728 ft²Bigger

Bigger than 68% of homes nearby

Lot size0.12 ac
SmallerTypical 0.14 acBigger

Bigger than 38% of homes nearby

Year built1909
OlderTypical 1930Newer

Newer than 16% of homes nearby

How 20 Porter St ranks against every home in each area.
MeasureThis homeEast WatertownWatertown 02472Middlesex County
Estimated valuepricier than$1,186,70880% of homes87% of homes80% of homes
Price per ft²pricier than$51727% of homes27% of homes63% of homes
Living areabigger than2,296 ft²57% of homes68% of homes68% of homes
Lot sizebigger than0.12 ac41% of homes38% of homes18% of homes
Year builtnewer than190920% of homes16% of homes17% of homes

About 20 Porter St

How much is 20 Porter St, Watertown, MA worth?

The TopHap Estimate for 20 Porter St, Watertown, MA is $1,186,708 as of Oct 21, 2026. The likely range is $1,066,821 to $1,306,595. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 20 Porter St, Watertown, MA last sell?

20 Porter St, Watertown, MA last sold on Sep 30, 2020 for $920,000, according to the county's recorded deed.

How big is 20 Porter St, Watertown, MA?

20 Porter St, Watertown, MA has 4 bedrooms, 3 bathrooms and 2,296 square feet of living space.

When was 20 Porter St, Watertown, MA built?

20 Porter St, Watertown, MA was built in 1909, making it 117 years old. It is a condo/apartment home. The building has 3 stories.

What schools serve 20 Porter St, Watertown, MA?

20 Porter St, Watertown, MA is assigned to Hosmer Elementary School (elementary), rated B; Watertown High School (high), rated C+; Watertown Middle School (middle), rated B-. All sit in Watertown School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 20 Porter St, Watertown, MA compare to other homes in Watertown 02472?

Among the 10,041 homes in Watertown 02472, it is worth more than 87% of them ($1,186,708 against a typical $811,593), its price per square foot is higher than 27% of them ($517 against a typical $584), it is bigger than 68% of them (2,296 ft² against a typical 1,728 ft²), its lot is bigger than 38% of them (0.12 ac against a typical 0.14 ac) and it is newer than 16% of them (1909 against a typical 1930). Measured against all of Middlesex County, it is worth more than 80% 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 20 Porter St, Watertown, MA?

The 2026 property tax bill for 20 Porter St, Watertown, MA was $11,600. The county assessed it at $950,800.

More homes on Porter St

Closest homes

More homes in Watertown 02472

Assigned schools

Explore the area

See this home in context

Open 20 Porter St on TopHap’s interactive map to compare it against every sale nearby, overlay school zones and flood risk, and run a CMA.

Open in map
A flyover of TopHap's photorealistic 3D map, with recorded sale prices pinned to homes
Search any address, city, zip, or county…3D$1.9M$6.25MOpen in map