San Mateo County property record for 451 W 20th Ave, San Mateo, CA 94403
| Property Type | Public School (Administration, Campus, Dorms, Instruction) |
|---|---|
| Lot Size | 6.38 acres (278,234 sqft) |
| Owner | 2 Company Names on Record |
| Tax Bill | $5,320 (2025) |
| Flood Zone | Zone X (minimal risk) |
| APN | 039-040-200 |
| Primary APN | 039-040-200 |
|---|
| Lot Area | 278,234 sqft |
|---|
| Street Address | 451 W 20TH AVE |
|---|---|
| City | SAN MATEO |
| State | CA |
| Zip | 94403-1335 |
| Property Category | Public Works |
| Property Type | Public Works > Public School (Administration, Campus, Dorms, Instruction) |
| Legal Description | PARCEL 4 RSM 77/61-62 |
| Jurisdiction | SAN MATEO CA |
| Township / Civil Division | SAN MATEO |
| Census Block Group | 1 |
| Census Block | 1005 |
| Census Tract | 607400 |
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 Company Names on Record |
|---|---|
| Mailing Address | 1301 POST ST, 102, SAN FRANCISCO, CA 94109-6667 |
| Occupancy | Owner Occupied |
| Owner Type | Company |
| 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 |
|---|---|---|
| 2026 | $34,789,962 (+2.18%) Land $745,804 Building $34,044,158 | |
| 2025 | $5,320.00 (+6,086.05%) Additional exemption filed | $34,047,945 (+15.92%) Land $731,181 Building $33,316,764 |
| 2023 | $86.00 Additional exemption filed | $29,372,596 Land $702,790 Building $28,669,806 |
| 2022 | $86.00 |
Assessed value is set for property tax purposes and is not a market price estimate.
Source: FEMA National Flood Hazard Layer, effective September 10, 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.
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 374 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 |
| Etheric Networks Fixed Wireless | 250 / 100 |
| T-Mobile Fixed Wireless | 100 / 20 |
May also be available: GeoLinks, Verizon.
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