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Single Family ResidenceResidential
$1,034,850$680 / 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 94How 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 $850,000 on Aug 5, 2022

3728 CASTLE ROCK RD

DIAMOND BAR, CA 91765
3
Beds
2
Baths
1,521 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.
0.17 ac
Lot SizeThe size of the land the home sits on, from county records.
1963
Year BuiltThe year the home was originally built, according to county records.

Valuation

$1M
$973K low$1.1M high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$850,000 · Aug 5, 2022
Est. Owner EquityRoughly how much of the home's value the owner would keep after paying off known loans. It is our estimate minus the loans still owed.$634,850
Est. Lendable EquityThe part of the owner's equity a lender would typically let them borrow against — about 80% of their equity.$507,880
Loan-to-ValueHow much is still owed on the home compared to what it is worth. 80% means loans equal 80% of our estimate, so it shifts when the estimate does.39%
1st MortgageA loan still believed to be open on this home, in the order lenders get repaid. The first position is paid back before the second.$400,000
UNITED WHOLESALE MORTGAGE · recorded Aug 5, 2022

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$11,332 (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.$884,340 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$707,472
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$176,868
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$867,000

Climate Risk

Projected Flood DepthHow deep a serious flood is expected to get here at some point in the next 30 years. Shown in inches.71 in
30-Year Flood ChanceThe chance of at least one serious flood here in the next 30 years, not in any single year.51%
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.Single Family Residence
CountyLOS ANGELES
Lot (acres)The size of the land the home sits on, from county records.0.17
ConstructionThe main material the home's frame and walls are built from.Wood (Unspecified)
HeatingThe type of heating system in the home.Central
PoolWhether the property has a pool, and what kind, such as in-ground.No

Transaction History(5)

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
Castle Rock Elementary SchoolA+
Elementary · Grades KG–5 · 0.8 mi
H
Diamond Bar High SchoolA+
High · Grades 9–12 · 1.6 mi
M
South Pointe Middle SchoolA+
Middle · Grades 6–8 · 2.0 mi

District: Walnut Valley Unified School District

Neighborhood · ZIP 91765These 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.46
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.101
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.388

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.35%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.9.2%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.7%
PopulationHow many people live in this area.41,302
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.2,738 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$98,979
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$125,933
Average tempThe average temperature here across a full year.63°F
Annual precipHow much rain and melted snow falls here in a typical year.19 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.73%

Ownership

OccupancyWhether the owner appears to live here or somewhere else. It is inferred from the mailing address on record.Owner occupied
Company ownedWhether the owner is a company or trust rather than a person.No

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

3728 Castle 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.

  • Worth more than 67% of homes in Los Angeles County
  • Costs more per square foot than 94% of homes in Diamond Bar 91765
  • Smaller than 66% of homes in Diamond Bar 91765
  • Has a smaller lot than 89% of homes in Diamond Bar 91765
  • Older than 92% of homes in Diamond Bar 91765

What homes are worth in Diamond Bar 91765

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

This home
$375K$3.2M

This home is worth more than 55% of homes in Diamond Bar 91765.

How it measures up in Diamond Bar 91765

The dot is this home. The mark in the middle is the typical home in Diamond Bar 91765.

Estimated value$1,034,850
CheaperTypical $987,611Pricier

Pricier than 55% of homes nearby

Price per ft²$680
CheaperTypical $537Pricier

Pricier than 94% of homes nearby

Living area1,521 ft²
SmallerTypical 1,811 ft²Bigger

Bigger than 34% of homes nearby

Lot size0.17 ac
SmallerTypical 0.25 acBigger

Bigger than 11% of homes nearby

Year built1963
OlderTypical 1979Newer

Newer than 8% of homes nearby

How 3728 Castle Rock Rd ranks against every home in each area.
MeasureThis homeDiamond Bar 91765Los Angeles County
Estimated valuepricier than$1,034,85055% of homes67% of homes
Price per ft²pricier than$68094% of homes70% of homes
Living areabigger than1,521 ft²34% of homes46% of homes
Lot sizebigger than0.17 ac11% of homes50% of homes
Year builtnewer than19638% of homes60% of homes

About 3728 Castle Rock Rd

How much is 3728 Castle Rock Rd, Diamond Bar, CA worth?

The TopHap Estimate for 3728 Castle Rock Rd, Diamond Bar, CA is $1,034,850 as of Jul 14, 2026. The likely range is $972,700 to $1,097,000. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 3728 Castle Rock Rd, Diamond Bar, CA last sell?

3728 Castle Rock Rd, Diamond Bar, CA last sold on Aug 5, 2022 for $850,000, according to the county's recorded deed. TopHap holds 3 recorded sales for this parcel.

How big is 3728 Castle Rock Rd, Diamond Bar, CA?

3728 Castle Rock Rd, Diamond Bar, CA has 3 bedrooms, 2 bathrooms, 1,521 square feet of living space and a 0.17-acre lot.

When was 3728 Castle Rock Rd, Diamond Bar, CA built?

3728 Castle Rock Rd, Diamond Bar, CA was built in 1963, making it 63 years old.

What schools serve 3728 Castle Rock Rd, Diamond Bar, CA?

3728 Castle Rock Rd, Diamond Bar, CA is assigned to Castle Rock Elementary School (elementary), rated A+; Diamond Bar High School (high), rated A+; South Pointe Middle School (middle), rated A+. All sit in Walnut Valley Unified School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 3728 Castle Rock Rd, Diamond Bar, CA compare to other homes in Diamond Bar 91765?

Among the 15,284 homes in Diamond Bar 91765, it is worth more than 55% of them ($1,034,850 against a typical $987,611), its price per square foot is higher than 94% of them ($680 against a typical $537), it is bigger than 34% of them (1,521 ft² against a typical 1,811 ft²), its lot is bigger than 11% of them (0.17 ac against a typical 0.25 ac) and it is newer than 8% of them (1963 against a typical 1979). Measured against all of Los Angeles County, it is worth more than 67% 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 3728 Castle Rock Rd, Diamond Bar, CA?

The 2025 property tax bill for 3728 Castle Rock Rd, Diamond Bar, CA was $11,332. The county assessed it at $884,340.

Closest homes

More homes in Diamond Bar 91765

Assigned schools

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