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Single Family ResidenceResidential
$3,661,962$968 / 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 Jul 14, 2026
Last sold for $3,311,500 on Dec 15, 2021

18 BIG ROCK RD

ORINDA, CA 94563
5
Beds
3.5
Baths
3,782 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.
0.58 ac
Lot SizeThe size of the land the home sits on, from county records.
2021
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

$3.7M
$3.3M low$4.1M high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$3,311,500 · Dec 15, 2021

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$44,347 (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.$3,121,000 (2026)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$1,413,000
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$1,708,000
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$3,197,000

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.39
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.
23
HeatProjected heat risk, scored 0 to 100, based on how many extremely hot days a year are expected. Higher is riskier.
53
StormProjected risk from heavy rainstorms, scored 0 to 100, based on how often extreme rainfall is expected. Higher is riskier.
36
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.2022
Lot (acres)The size of the land the home sits on, from county records.0.58
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.No

Transaction History(6)

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
Wagner Ranch Elementary SchoolA+
Elementary · Grades KG–5 · 2.4 mi
M
Orinda Intermediate SchoolA+
Middle · Grades 6–8 · 2.4 mi
H
Miramonte High SchoolA+
High · Grades 9–12 · 2.8 mi

District: Orinda Union Elementary School District

Neighborhood · ZIP 94563These 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.69
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.84
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.469

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.39%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.3.6%
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.19,466
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.850 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$217,768
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$332,191
Average tempThe average temperature here across a full year.57°F
Annual precipHow much rain and melted snow falls here in a typical year.27 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

18 Big Rock Rd 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.

  • Among the most valuable homes in Contra Costa County
  • Costs more per square foot than 98% of homes in Contra Costa County
  • Bigger than 96% of homes in Contra Costa County
  • Has a bigger lot than 94% of homes in Contra Costa County
  • Among the newest homes in Orinda 94563

What homes are worth in Orinda 94563

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

This home
$955K$4.4M

This home is worth more than 95% of homes in Orinda 94563.

How it measures up in Orinda 94563

The dot is this home. The mark in the middle is the typical home in Orinda 94563.

Estimated value$3,661,962
CheaperTypical $1,905,764Pricier

Pricier than 95% of homes nearby

Price per ft²$968
CheaperTypical $778Pricier

Pricier than 90% of homes nearby

Living area3,782 ft²
SmallerTypical 2,511 ft²Bigger

Bigger than 87% of homes nearby

Lot size0.58 ac
SmallerTypical 0.5 acBigger

Bigger than 63% of homes nearby

Year built2021
OlderTypical 1958Newer

Newer than almost all homes nearby

How 18 Big Rock Rd ranks against every home in each area.
MeasureThis homeWilderOrinda 94563Contra Costa County
Estimated valuepricier than$3,661,96288% of homes95% of homesalmost all homes
Price per ft²pricier than$96886% of homes90% of homes98% of homes
Living areabigger than3,782 ft²56% of homes87% of homes96% of homes
Lot sizebigger than0.58 ac83% of homes63% of homes94% of homes
Year builtnewer than202194% of homesalmost all homesalmost all homes

About 18 Big Rock Rd

How much is 18 Big Rock Rd, Orinda, CA worth?

The TopHap Estimate for 18 Big Rock Rd, Orinda, CA is $3,661,962 as of Jul 14, 2026. The likely range is $3,268,341 to $4,055,583. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 18 Big Rock Rd, Orinda, CA last sell?

18 Big Rock Rd, Orinda, CA last sold on Dec 15, 2021 for $3,311,500, according to the county's recorded deed. TopHap holds 4 recorded sales for this parcel.

How big is 18 Big Rock Rd, Orinda, CA?

18 Big Rock Rd, Orinda, CA has 5 bedrooms, 3.5 bathrooms, 3,782 square feet of living space and a 0.58-acre lot.

When was 18 Big Rock Rd, Orinda, CA built?

18 Big Rock Rd, Orinda, CA was built in 2021, making it 5 years old. The building has 1 story.

What schools serve 18 Big Rock Rd, Orinda, CA?

18 Big Rock Rd, Orinda, CA is assigned to Wagner Ranch Elementary School (elementary), rated A+; Orinda Intermediate School (middle), rated A+; Miramonte High School (high), rated A+. All sit in Orinda Union Elementary School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 18 Big Rock Rd, Orinda, CA compare to other homes in Orinda 94563?

Among the 7,027 homes in Orinda 94563, it is worth more than 95% of them ($3,661,962 against a typical $1,905,764), its price per square foot is higher than 90% of them ($968 against a typical $778), it is bigger than 87% of them (3,782 ft² against a typical 2,511 ft²), its lot is bigger than 63% of them (0.58 ac against a typical 0.5 ac) and it is newer than almost all of them (2021 against a typical 1958). Measured against all of Contra Costa County, it is worth more than almost all 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 18 Big Rock Rd, Orinda, CA?

The 2025 property tax bill for 18 Big Rock Rd, Orinda, CA was $44,347. The county assessed it at $3,121,000.

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