Contra Costa County property record for 5121 Roundup Ct, Antioch, CA 94531
| Property Type | Single Family Home |
|---|---|
| Details | 3 bd · 2 ba · 1,321 sqft · built 1995 |
| Lot Size | 0.129 acres (5,600 sqft) |
| Owner | 2 Individual Names on Record |
| Last Sale | $335,000 (Dec 2015) |
| Tax Bill | $4,879 (2025) |
| Flood Zone | Zone X (minimal risk) |
| APN | 056-240-002-8 |
| Primary APN | 056-240-002-8 |
|---|---|
| Alternative APN |
|
| Bedrooms | 3 Beds |
|---|---|
| Full Baths | 2 Baths |
| Total Rooms | 6 Rooms |
| Stories | 1 Story |
| Building Area | 1,321 sqft Living Area |
| 1st Floor Area | 1,321 sqft |
| Year Built | Built 1995 |
|---|---|
| Effective Year Built | Effective 1998 |
| Lot Area | 5,600 sqft (0.129 acres) |
| Garage Type | Attached |
| Garage Area | 475 sqft |
| Parking Spaces | 2 Parking Spaces |
| Heating System | Central |
|---|
| Street Address | 5121 ROUNDUP CT |
|---|---|
| City | ANTIOCH |
| State | CA |
| Zip | 94531-8474 |
| Property Category | Residential |
| Property Type | Residential > Single Family > Home |
| Legal Description | T7620 L486 |
| Legal Tract | 7620 |
| Legal Lot Number | 486 |
| Jurisdiction | CONTRA COSTA CA |
| Township / Civil Division | EAST CONTRA COSTA |
| Census Block Group | 1 |
| Census Block | 1011 |
| Census Tract | 303207 |
Source: NPS National Register of Historic Places, as of August 1, 2026
| Historic District | Within the Shannon-Williamson Ranch listed 1987 · 12 contributing resources · NRIS 87000003 |
|---|
Federal listing alone does not restrict alterations; local historic district rules, which this data does not cover, may apply.
Source: Contra Costa County records, as of July 14, 2026
Owner names and exact recorded amounts shown locked on this page are available instantly with a free trial.
| Owner of Record | 2 Individual Names on Record |
|---|---|
| Mailing Address | 2238 LAKE VILLA CT, MARTINEZ, CA 94553-5464 |
| Owner Type | Individual |
| Vesting | Joint Tenants |
| Deed Names | 2 Names on Deed |
|---|---|
| Last Sale | Dec 29, 2015 · Amount on Record |
| Deed Sale | Dec 29, 2015 · Amount on Record |
| Prior Sale | Oct 26, 2015 · Amount on Record |
| Deed Document Number | 2015266617 |
| Prior Transfer Date | Feb 22, 2006 |
| Prior Transfer Doc | 0000069120 |
| Record Updated | Sep 20, 2026 |
Source: Contra Costa County assessment roll, as of July 14, 2026
| Type | Name |
|---|---|
| State | California |
| County | Contra Costa County |
| Municipality | Antioch City |
| Unified School District | Antioch Unified School District (KG - 12) |
| Year | Tax Bill | Assessed Value |
|---|---|---|
| 2026 | $404,494 (+2%) Land $108,669 Building $295,825 | |
| 2025 | $4,879.00 (+6.2%) | $396,564 (+4.04%) Land $106,539 Building $290,025 |
| 2023 | $4,594.00 (+1.52%) | $381,166 Land $102,402 Building $278,764 |
| 2022 | $4,525.00 |
Assessed value is set for property tax purposes and is not a market price estimate.
Source: FEMA National Flood Hazard Layer, effective October 12, 2026
| FEMA Flood Zone | Zone X minimal risk |
|---|---|
| Flood Insurance Requirement | Not required lenders may require it |
Values are read at the parcel center point; lenders make the official flood determination.
Source: USDA Forest Service Wildfire Risk to Communities (2nd edition), as of 2024
| Wildfire Risk | Low lower than 62% of the US · lower than 77% of California |
|---|---|
| Wildfire Likelihood | 0.06% annual chance |
| Exposure | Indirect within ember reach |
Values cover an area roughly 900 ft across, not the parcel itself; insurers use their own ratings.
Source: EPA Safe Drinking Water Information System, as of September 2026
| Water System | CITY OF ANTIOCH serves 116,781 people · EPA ID CA0710001 |
|---|---|
| Water Source | Surface water |
| Last State Inspection | Jan 2024 |
| Lead | Under 1 ppb (2022–2024) action level 15 ppb |
| Water Quality | None last 10 years |
|---|---|
| Treatment and Procedure | None last 10 years |
| Monitoring and Reporting | None last 3 years |
Results are for the whole water system, not water tested at this address; lead at the tap also depends on the building's own pipes.
Source: FCC Broadband Data Collection, based on 638 locations within half a mile, as of December 31, 2025
| Provider | Max Down / Up (Mbps) |
|---|---|
| Xfinity Cable | 2,000 / 250 |
| Unwired Fixed Wireless | 300 / 25 |
| Verizon Fixed Wireless | 300 / 20 |
| AT&T DSL | 100 / 20 |
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