| Primary address | 20021 Onyx Court, Castro Valley |
| Zip code | 94546 |
| County | Alameda |
| Parcel ID | 84C-669-55 |
View detailed information on past sales, title documents and property taxes, including the assessed market value, in their dedicated tabs.
| Current property tax | $2,030 |
| Building sqft | 1,631 |
| Building class | Single Family Residential Homes Used as Such (1100) |
| Acreage | 0.13 |
| Units | 1 |
| Year built | 1947 |
| Stories | 1 |
| Bedrooms | 3 |
| Bathrooms | 2 |
| Zoning district | Single Family Residential (R1-CSU-RV) |
| School district | Castro Vly Unif SCH |
View more neighborhood information such as transportation, nearby schools and risk designations in the dedicated tab.
Property reports include comprehensive occupancy, improvement and development information (where available).
Create a free account to access valuable data points such as:
20021 Onyx Court, Castro Valley, CA 94546 was built in 1947 and has a total of 1,631 square feet.
What is the assessed value of 20021 Onyx Court, Castro Valley, CA 94546 and the property tax paid?Assessed at $181,389, the tax amount paid for 20021 Onyx Court, Castro Valley, CA 94546 is $2,111.
When was 20021 Onyx Court, Castro Valley, CA 94546 last sold?20021 Onyx Court, Castro Valley, CA 94546 was last sold in 06/30/2025.
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Create a free account to view the complete sales history for 20021 Onyx Court, Castro Valley, including title documents, transfer conditions, mortgages and liens.
To view the complete history of deeds, mortgages, assignments of leases and rents, and more, sign up for free. Available data goes back to 1966.
R: Recorded date
D: Document date
Access detailed property tax data for 20021 Onyx Court, Castro Valley, CA 94546. Tax information included: property tax, market value and assessed value, exemptions, abatements, and assessment history.
| Tax year: | 2025-2026 |
| Base tax | $2,111 |
| Current property tax | $2,030 |
| Market value | $181,389 |
Here's the assessment & property tax history for 20021 Onyx Court, Castro Valley, including the evolution of the total tax rate and corresponding property tax.
| Year | Assessment value | Total tax rate | Property tax | Year over year change |
|---|---|---|---|---|
| 2025-2026 | $181,389 | 1.164 | $2,111 | +0.69% |
| 2024-2025 | $177,833 | 1.1791 | $2,097 | -48.84% |
| 2023-2024 | $174,346 | 2.3508 | $4,099 | +101.36% |
| 2022-2023 | $170,928 | 1.1908 | $2,035 | +2.54% |
| 2021-2022 | $167,577 | 1.1848 | $1,985 | +2.26% |
The complete history of permits filed for 20021 Onyx Court, Castro Valley, including new construction or demolition permits, plus any work pertaining to plumbing, heating and sprinkler systems is available with a free account. Available data goes back to 1990.
Access a detailed real estate market overview of Castro Valley so you can assess current trends, home values, types of properties sold and transaction volume. View the median home sale price in Castro Valley and compare it to other neighborhoods in Alameda County.
Check out recently sold homes in Castro-Valley and see how their prices compare.
Create a free account to unlock extended information for 20021 Onyx Court, Castro Valley, including whether it's located in FEMA flood zones, floodways or special flood hazard areas, as well as the Coastal barriers resources system area (COBRA).
| FEMA flood zone(s) | X (See more on map) |
| Fire hazard zone | See more on map |
| Faults and tsunami inundation zone map | Register |
| Landslides and liquefaction map | Register |
Access the detailed traffic volume map for 20021 Onyx Court, Castro Valley to see estimated average daily traffic on streets surrounding the property as well as the types of properties in its vicinity.
| View daily traffic map |
| Name | Rating | Type | Grade range | No of students | Distance to school (mi) |
|---|---|---|---|---|---|
| Marshall Elementary School | 9 | Public | K-5 | 491 | 0.14 |
| Early Bird Montessori School | NR | Private | PK, K-1 | 30 | 0.39 |
| Early Bird Montessori School | NR | Private | PK, K-1 | 30 | 0.39 |
| Vannoy Elementary School | 7 | Public | K-5 | 441 | 0.68 |
| Independent Elementary School | 8 | Public | K-5 | 634 | 0.70 |
| Name | Rating | Type | Grade range | No of students | Distance to school (mi) |
|---|---|---|---|---|---|
| Creekside Middle School | 8 | Public | 6-8 | 760 | 0.17 |
| Castro Valley Adult And Career Education | NR | Public | 0 | 0.80 | |
| Canyon Middle School | 6 | Public | 6-8 | 1,332 | 0.82 |
| Redwood Christian Schools | NR | Private | K-12 | 706 | 0.83 |
| Special Education-Preschool-Laurel | NR | Public | 1 | 0.83 |
| Name | Rating | Type | Grade range | No of students | Distance to school (mi) |
|---|---|---|---|---|---|
| Castro Valley Adult And Career Education | NR | Public | 0 | 0.80 | |
| Redwood Christian Schools | NR | Private | K-12 | 706 | 0.83 |
| Special Education-Preschool-Laurel | NR | Public | 1 | 0.83 | |
| Alma Preschool | NR | Public | 52 | 0.83 | |
| Castro Valley High School | 9 | Public | 9-12 | 2,799 | 0.92 |
Data provided by GreatSchools.org © 2025. All rights reserved.
Here are the neighbors for 20021 Onyx Court, Castro Valley.