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Single Family ResidenceResidential
$1,048,923$490 / 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 Sep 24, 2026
Last sold for $1,050,000 on Oct 14, 2025

20 MT TAMALPAIS PL

CLAYTON, CA 94517
4
Beds
2.5
Baths
2,141 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.
0.26 ac
Lot SizeThe size of the land the home sits on, from county records.
1975
Year BuiltThe year the home was originally built, according to county records.
1
StoriesHow many floors the home has above ground.
9
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

$1M
$941K low$1.2M high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$1,050,000 · Oct 14, 2025

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$7,166 (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.$1,050,000 (2026)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$500,000
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$550,000
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$533,864

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.36
1
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
83
WildfireProjected wildfire risk, scored 0 to 100, based on how much land burns in a typical year. Higher is riskier.
46
HeatProjected heat risk, scored 0 to 100, based on how many extremely hot days a year are expected. Higher is riskier.
40
StormProjected risk from heavy rainstorms, scored 0 to 100, based on how often extreme rainfall is expected. Higher is riskier.
14
DroughtProjected water shortage risk, scored 0 to 100. Higher means more strain on the local water supply.

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
CountyCONTRA COSTA
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.1976
Lot (acres)The size of the land the home sits on, from county records.0.26
GarageWhether the property has a garage, and details like whether it is attached to the home.Garage, Attached
PoolWhether the property has a pool, and what kind, such as in-ground.Yes

Transaction History(4)

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.

M
Diablo View Middle SchoolA-
Middle · Grades 6–8 · 0.8 mi
E
Mt. Diablo Elementary SchoolA
Elementary · Grades KG–5 · 1.0 mi
H
Northgate High SchoolA
High · Grades 9–12 · 4.2 mi

District: Mount Diablo Unified School District

Neighborhood · ZIP 94517These 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.38
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.86
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.481

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.98%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.37%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.2.8%
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.12,675
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.266 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$151,382
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$185,430
Average tempThe average temperature here across a full year.58°F
Annual precipHow much rain and melted snow falls here in a typical year.22 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.78%

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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

20 Mt Tamalpais Pl 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 69% of homes in Contra Costa County
  • Costs more per square foot than 76% of homes in Dana Hills
  • Bigger than 67% of homes in Contra Costa County
  • Has a bigger lot than 81% of homes in Contra Costa County
  • Older than 72% of homes in Clayton 94517

What homes are worth in Clayton 94517

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

This home
$535K$1.8M

This home is worth more than 61% of homes in Clayton 94517.

How it measures up in Clayton 94517

The dot is this home. The mark in the middle is the typical home in Clayton 94517.

Estimated value$1,048,923
CheaperTypical $997,813Pricier

Pricier than 61% of homes nearby

Price per ft²$490
CheaperTypical $463Pricier

Pricier than 67% of homes nearby

Living area2,141 ft²
SmallerTypical 2,045 ft²Bigger

Bigger than 57% of homes nearby

Lot size0.26 ac
SmallerTypical 0.24 acBigger

Bigger than 58% of homes nearby

Year built1975
OlderTypical 1980Newer

Newer than 28% of homes nearby

How 20 Mt Tamalpais Pl ranks against every home in each area.
MeasureThis homeDana HillsClayton 94517Contra Costa County
Estimated valuepricier than$1,048,92344% of homes61% of homes69% of homes
Price per ft²pricier than$49076% of homes67% of homes57% of homes
Living areabigger than2,141 ft²40% of homes57% of homes67% of homes
Lot sizebigger than0.26 ac76% of homes58% of homes81% of homes
Year builtnewer than197553% of homes28% of homes47% of homes

About 20 Mt Tamalpais Pl

How much is 20 Mt Tamalpais Pl, Clayton, CA worth?

The TopHap Estimate for 20 Mt Tamalpais Pl, Clayton, CA is $1,048,923 as of Sep 24, 2026. The likely range is $941,207 to $1,156,639. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 20 Mt Tamalpais Pl, Clayton, CA last sell?

20 Mt Tamalpais Pl, Clayton, CA last sold on Oct 14, 2025 for $1,050,000, according to the county's recorded deed. TopHap holds 2 recorded sales for this parcel.

How big is 20 Mt Tamalpais Pl, Clayton, CA?

20 Mt Tamalpais Pl, Clayton, CA has 4 bedrooms, 2.5 bathrooms, 2,141 square feet of living space and a 0.26-acre lot.

When was 20 Mt Tamalpais Pl, Clayton, CA built?

20 Mt Tamalpais Pl, Clayton, CA was built in 1975, making it 51 years old. The building has 1 story.

What schools serve 20 Mt Tamalpais Pl, Clayton, CA?

20 Mt Tamalpais Pl, Clayton, CA is assigned to Diablo View Middle School (middle), rated A-; Mt. Diablo Elementary School (elementary), rated A; Northgate High School (high), rated A. All sit in Mount Diablo Unified School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 20 Mt Tamalpais Pl, Clayton, CA compare to other homes in Clayton 94517?

Among the 4,550 homes in Clayton 94517, it is worth more than 61% of them ($1,048,923 against a typical $997,813), its price per square foot is higher than 67% of them ($490 against a typical $463), it is bigger than 57% of them (2,141 ft² against a typical 2,045 ft²), its lot is bigger than 58% of them (0.26 ac against a typical 0.24 ac) and it is newer than 28% of them (1975 against a typical 1980). Measured against all of Contra Costa County, it is worth more than 69% 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 Mt Tamalpais Pl, Clayton, CA?

The 2025 property tax bill for 20 Mt Tamalpais Pl, Clayton, CA was $7,166. The county assessed it at $1,050,000.

More homes on Mt Tamalpais Pl

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