San Mateo County property record for 258 W 40th Ave, San Mateo, CA 94403
| Property Type | Single Family Home |
|---|---|
| Details | 3 bd · 1.5 ba · 1,780 sqft · built 1948 |
| Lot Size | 0.116 acres (5,046 sqft) |
| Owner | 2 Individual Names on Record |
| Tax Bill | $6,779 (2025) |
| Flood Zone | Zone X (minimal risk) |
| APN | 042-221-080 |
| Primary APN | 042-221-080 |
|---|
| Bedrooms | 3 Beds |
|---|---|
| Full Baths | 1.5 Baths |
| Half Baths | 1 Half Bath |
| Total Rooms | 9 Rooms |
| Building Area | 1,780 sqft Living Area |
| Gross Area | 2,100 sqft |
| 1st Floor Area | 1,180 sqft |
| Basement Area | 460 sqft |
| Finished Basement | 140 sqft |
| Unfinished Basement | 320 sqft |
| Family Room | Family Room |
| Study | Study |
| Year Built | Built 1948 |
|---|---|
| Effective Year Built | Effective 1948 |
| Lot Area | 5,046 sqft (0.116 acres) |
| Lot Dimensions | 95 ft deep x 53 ft wide |
| Garage Type | Basement |
| Garage Area | 320 sqft |
| Parking Spaces | 1 Parking Space |
| Cooling System | Central |
|---|---|
| Heating System | Central |
| Street Address | 258 W 40TH AVE |
|---|---|
| City | SAN MATEO |
| State | CA |
| Zip | 94403-4350 |
| Property Category | Residential |
| Property Type | Residential > Single Family > Home |
| Local Zoning Code | R10006 |
| Legal Description | LOT 8 BLOCK 11 SAN MATEO KNOLLS RSM 22/8 9 CITY OF SAN MATEO |
| Legal Subdivision | SAN MATEO KNOLLS |
| Legal Block | 11 |
| Legal Lot Number | 8 |
| Jurisdiction | SAN MATEO CA |
| Township / Civil Division | SAN MATEO |
| Census Block Group | 2 |
| Census Block | 2000 |
| Census Tract | 607100 |
Source: San Mateo County records, as of July 15, 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 | 214 42ND AVE, SAN MATEO, CA 94403-5002 |
| Occupancy | Owner Occupied |
| Owner Type | Individual |
| Deed Names | 2 Names on Deed |
|---|---|
| Record Updated | Sep 20, 2026 |
Source: San Mateo County assessment roll, as of July 15, 2026
| Type | Name |
|---|---|
| State | California |
| County | San Mateo County |
| Municipality | San Mateo City |
| Elementary School District | San Mateo-Foster City Elementary School District (KG - 08) |
| Secondary School District | San Mateo Union High School District (09 - 12) |
| Year | Tax Bill | Assessed Value | Assessed Market Value |
|---|---|---|---|
| 2026 | $423,491 (+2%) Land $181,205 Building $242,286 | ||
| 2025 | $6,779.00 (+2.39%) Homeowner's exemption | $415,188 (+4.04%) Land $177,652 Building $237,536 | |
| 2023 | $6,621.00 (+1.94%) Homeowner's exemption | $399,067 Land $170,754 Building $228,313 | $1,903,950 |
| 2022 | $6,495.00 |
Assessed value and assessed market value are set for property tax purposes and are not market price estimates.
Source: FEMA National Flood Hazard Layer, effective September 10, 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 | 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 | CALIFORNIA WATER SERVICE - SAN MATEO private · serves 103,536 people · EPA ID CA4110008 |
|---|---|
| Water Source | Purchased surface water from SAN FRANCISCO REGIONAL WATER SYSTEM |
| Last State Inspection | Mar 2025 |
| Lead | 4 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 785 locations within half a mile, as of December 31, 2025
| Provider | Max Down / Up (Mbps) |
|---|---|
| Sonic Telecom Fiber | 10,000 / 10,000 |
| AT&T Fiber · Fixed Wireless, DSL in parts of the area | 5,000 / 5,000 |
| Xfinity Cable | 2,000 / 250 |
| Astound Broadband Cable | 1,500 / 50 |
| Verizon Fixed Wireless | 300 / 20 |
| Etheric Networks Fixed Wireless | 250 / 100 |
May also be available: GeoLinks, T-Mobile.
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