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Single Family ResidenceResidential
$875,110$223 / 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 97How 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 $669,000 on Apr 17, 2020

3105 CASTLE ROCK LOOP

DISCOVERY BAY, CA 94505
5
Beds
4
Baths
3,917 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.
0.25 ac
Lot SizeThe size of the land the home sits on, from county records.
2003
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.
2
ParkingThe number of parking spaces on the property, including the garage.

Valuation

$875K
$845K low$906K high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$669,000 · Apr 17, 2020

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$10,128 (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.$746,276 (2026)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$111,550
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$634,726
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$731,644

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.38
25
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
75
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.
19
StormProjected risk from heavy rainstorms, scored 0 to 100, based on how often extreme rainfall is expected. Higher is riskier.
25
DroughtProjected water shortage risk, scored 0 to 100. Higher means more strain on the local water supply.
Projected Flood DepthHow deep a serious flood is expected to get here at some point in the next 30 years. Shown in inches.3 in
30-Year Flood ChanceThe chance of at least one serious flood here in the next 30 years, not in any single year.6%
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.0.2 percent flood zone

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.2004
Lot (acres)The size of the land the home sits on, from county records.0.25
CoolingThe type of cooling or air conditioning in the home.Central
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
Timber Point Elementary SchoolB
Elementary · Grades KG–5 · 0.7 mi
M
Excelsior Middle SchoolB-
Middle · Grades 6–8 · 3.0 mi
H
Liberty High SchoolB
High · Grades 9–12 · 4.6 mi

District: Byron Union Elementary School District

Neighborhood · ZIP 94505These 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.100
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 100.340

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.92%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.22%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.6.3%
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.9,105
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.519 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$128,285
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$156,258
Average tempThe average temperature here across a full year.61°F
Annual precipHow much rain and melted snow falls here in a typical year.13 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

3105 Castle Rock Loop 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 94% of homes in Lakeshore
  • Among the lowest price per square foot in Contra Costa County
  • Bigger than 96% of homes in Contra Costa County
  • Has a bigger lot than 97% of homes in Lakeshore
  • Newer than 87% of homes in Contra Costa County

What homes are worth in Discovery Bay 94505

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

This home
$469K$1.5M

This home is worth more than 69% of homes in Discovery Bay 94505.

How it measures up in Discovery Bay 94505

The dot is this home. The mark in the middle is the typical home in Discovery Bay 94505.

Estimated value$875,110
CheaperTypical $776,672Pricier

Pricier than 69% of homes nearby

Price per ft²$223
CheaperTypical $330Pricier

Pricier than 4% of homes nearby

Living area3,917 ft²
SmallerTypical 2,405 ft²Bigger

Bigger than 95% of homes nearby

Lot size0.25 ac
SmallerTypical 0.16 acBigger

Bigger than 95% of homes nearby

Year built2003
OlderTypical 1994Newer

Newer than 73% of homes nearby

How 3105 Castle Rock Loop ranks against every home in each area.
MeasureThis homeLakeshoreDiscovery Bay 94505Contra Costa County
Estimated valuepricier than$875,11094% of homes69% of homes61% of homes
Price per ft²pricier than$22320% of homes4% of homesalmost no homes
Living areabigger than3,917 ft²92% of homes95% of homes96% of homes
Lot sizebigger than0.25 ac97% of homes95% of homes79% of homes
Year builtnewer than200376% of homes73% of homes87% of homes

About 3105 Castle Rock Loop

How much is 3105 Castle Rock Loop, Discovery Bay, CA worth?

The TopHap Estimate for 3105 Castle Rock Loop, Discovery Bay, CA is $875,110 as of Sep 24, 2026. The likely range is $844,670 to $905,550. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 3105 Castle Rock Loop, Discovery Bay, CA last sell?

3105 Castle Rock Loop, Discovery Bay, CA last sold on Apr 17, 2020 for $669,000, according to the county's recorded deed. TopHap holds 2 recorded sales for this parcel.

How big is 3105 Castle Rock Loop, Discovery Bay, CA?

3105 Castle Rock Loop, Discovery Bay, CA has 5 bedrooms, 4 bathrooms, 3,917 square feet of living space and a 0.25-acre lot.

When was 3105 Castle Rock Loop, Discovery Bay, CA built?

3105 Castle Rock Loop, Discovery Bay, CA was built in 2003, making it 23 years old. The building has 2 stories.

What schools serve 3105 Castle Rock Loop, Discovery Bay, CA?

3105 Castle Rock Loop, Discovery Bay, CA is assigned to Timber Point Elementary School (elementary), rated B; Excelsior Middle School (middle), rated B-; Liberty High School (high), rated B. All sit in Byron Union Elementary School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 3105 Castle Rock Loop, Discovery Bay, CA compare to other homes in Discovery Bay 94505?

Among the 6,088 homes in Discovery Bay 94505, it is worth more than 69% of them ($875,110 against a typical $776,672), its price per square foot is higher than 4% of them ($223 against a typical $330), it is bigger than 95% of them (3,917 ft² against a typical 2,405 ft²), its lot is bigger than 95% of them (0.25 ac against a typical 0.16 ac) and it is newer than 73% of them (2003 against a typical 1994). Measured against all of Contra Costa County, it is worth more than 61% 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 3105 Castle Rock Loop, Discovery Bay, CA?

The 2025 property tax bill for 3105 Castle Rock Loop, Discovery Bay, CA was $10,128. The county assessed it at $746,276.

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