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Single Family ResidenceResidential
$1,052,529$466 / 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 Aug 30, 2026

335 ROUNDHILL CT

CLAYTON, CA 94517
4
Beds
2.5
Baths
2,258 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.
1977
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
12
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.
1
ParkingThe number of parking spaces on the property, including the garage.

Valuation

$1.1M
$996K low$1.1M high

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$5,300 (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.$378,253 (2026)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$102,565
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$275,688
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$370,837

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.
76
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
StyleThe architectural style of the home, such as ranch or colonial.Ranch
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.1978
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.Wood Shingle
HeatingThe type of heating system in the home.Forced Air With Air Conditioning
CoolingThe type of cooling or air conditioning in the home.Central
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, Attached
PoolWhether the property has a pool, and what kind, such as in-ground.Yes

Transaction History(3)

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
Mt. Diablo Elementary SchoolA+
Elementary · Grades KG–5 · 0.6 mi
M
Diablo View Middle SchoolA
Middle · Grades 6–8 · 0.7 mi
H
Concord High SchoolC+
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

335 Roundhill Ct 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 70% of homes in Contra Costa County
  • Bigger than 71% of homes in Contra Costa County
  • Has a bigger lot than 83% of homes in Contra Costa County

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
$523K$1.8M

This home is worth more than 57% 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$1,052,529
CheaperTypical $1,019,230Pricier

Pricier than 57% of homes nearby

Price per ft²$466
CheaperTypical $470Pricier

Pricier than 47% of homes nearby

Living area2,258 ft²
SmallerTypical 2,033 ft²Bigger

Bigger than 61% of homes nearby

Lot size0.28 ac
SmallerTypical 0.24 acBigger

Bigger than 63% of homes nearby

Year built1977
OlderTypical 1980Newer

Newer than 43% of homes nearby

How 335 Roundhill Ct ranks against every home in each area.
MeasureThis homeClayton 94517Contra Costa County
Estimated valuepricier than$1,052,52957% of homes70% of homes
Price per ft²pricier than$46647% of homes52% of homes
Living areabigger than2,258 ft²61% of homes71% of homes
Lot sizebigger than0.28 ac63% of homes83% of homes
Year builtnewer than197743% of homes51% of homes

About 335 Roundhill Ct

How much is 335 Roundhill Ct, Clayton, CA worth?

The TopHap Estimate for 335 Roundhill Ct, Clayton, CA is $1,052,529 as of Aug 30, 2026. The likely range is $995,607 to $1,109,452. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 335 Roundhill Ct, Clayton, CA last sell?

335 Roundhill Ct, Clayton, CA last sold on Jan 1, 1900, according to the county's recorded deed.

How big is 335 Roundhill Ct, Clayton, CA?

335 Roundhill Ct, Clayton, CA has 4 bedrooms, 2.5 bathrooms, 2,258 square feet of living space and a 0.28-acre lot.

When was 335 Roundhill Ct, Clayton, CA built?

335 Roundhill Ct, Clayton, CA was built in 1977, making it 49 years old. It is a ranch home. The building has 2 stories.

What schools serve 335 Roundhill Ct, Clayton, CA?

335 Roundhill Ct, Clayton, CA is assigned to Mt. Diablo Elementary School (elementary), rated A+; Diablo View Middle School (middle), rated A; Concord High School (high), rated C+. All sit in Mount Diablo Unified School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 335 Roundhill Ct, Clayton, CA compare to other homes in Clayton 94517?

Among the 4,550 homes in Clayton 94517, it is worth more than 57% of them ($1,052,529 against a typical $1,019,230), its price per square foot is higher than 47% of them ($466 against a typical $470), it is bigger than 61% of them (2,258 ft² against a typical 2,033 ft²), its lot is bigger than 63% of them (0.28 ac against a typical 0.24 ac) and it is newer than 43% of them (1977 against a typical 1980). Measured against all of Contra Costa County, it is worth more than 70% 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 335 Roundhill Ct, Clayton, CA?

The 2025 property tax bill for 335 Roundhill Ct, Clayton, CA was $5,300. The county assessed it at $378,253.

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