Contra Costa County property record for 501 William Way, Martinez, CA 94553
| Property Type | Federal Property (Exempt) |
|---|---|
| Lot Size | 0.817 acres (35,606 sqft) |
| Owner | Company Name on File |
| Tax Bill | $94 (2023) |
| Flood Zone | Zone X (minimal risk) |
| APN | 162-580-068-3 |
| Primary APN | 162-580-068-3 |
|---|---|
| Alternative APN |
|
| Lot Area | 35,606 sqft (0.817 acres) |
|---|
| Street Address | 501 WILLIAM WAY |
|---|---|
| City | MARTINEZ |
| State | CA |
| Zip | 94553-4764 |
| Property Category | Public Works |
| Property Type | Public Works > Federal Property (Exempt) |
| Legal Description | T9358 PCL C DED TO CITY |
| Jurisdiction | CONTRA COSTA CA |
| Township / Civil Division | CENTRAL CONTRA COSTA |
| Census Block Group | 3 |
| Census Block | 3014 |
| Census Tract | 321101 |
501 William Way, a public works property, is owned by a company.
Source: Contra Costa County records, as of July 14, 2026
Owner names and exact recorded amounts are on file and can be viewed instantly on this page with a free 10-day trial.
| Owner of Record | Company Name on File |
|---|---|
| Mailing Address | 525 HENRIETTA ST, MARTINEZ, CA 94553-2337 |
| Owner Type | Company |
| Deed Names | Name on Deed |
|---|---|
| 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 | Martinez City |
| Unified School District | Mount Diablo Unified School District (KG - 12) |
| Year | Tax Bill | Assessed Value |
|---|---|---|
| 2026 | $122,298 (+2%) Land $122,298 | |
| 2025 | $119,900 Land $119,900 | |
| 2023 | $94.00 (+526.67%) | $1 Land $1 |
| 2022 | $15.00 |
Assessed value is set for property tax purposes and is not a market price estimate.
FEMA maps place 501 William Way in Zone X, an area of minimal flood risk.
Source: FEMA National Flood Hazard Layer, effective October 12, 2026 · OpenFEMA NFIP redacted claims and policies, as of September 2026
| FEMA Flood Zone | Zone X minimal risk |
|---|---|
| Flood Insurance Requirement | Not required lenders may require it |
| Nearby Flood Policies | 1 in force |
Values are read at the parcel center point; flood claims are located to the census block group, not this parcel; lenders make the official flood determination.
The area around 501 William Way has no burnable land within ember reach, so its wildfire risk is not rated.
Source: USDA Forest Service Wildfire Risk to Communities (2nd edition), as of 2024
| Wildfire Risk | Not rated no burnable land 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 MARTINEZ serves 31,015 people · EPA ID CA0710006 |
|---|---|
| Water Source | Purchased surface water from CONTRA COSTA WATER DISTRICT |
| Last State Inspection | Oct 2025 |
| Lead | Under 1 ppb (2023–2025) 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 528 locations within half a mile, as of December 31, 2025
| Provider | Max Down / Up (Mbps) |
|---|---|
| Xfinity Cable | 2,000 / 250 |
| Astound Broadband Fiber · Cable in parts of the area | 1,500 / 1,500 |
| Unwired Fixed Wireless | 300 / 25 |
| T-Mobile Fixed Wireless | 100 / 20 |
| AT&T DSL · Fiber in parts of the area | 100 / 20 |
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