San Mateo County property record for 291 Polhemus Ave, Atherton, CA 94027
| Property Type | Single Family Home |
|---|---|
| Details | 5 bd · 8.5 ba · 11,700 sqft · built 2004 |
| Lot Size | 1.06 acres (46,224 sqft) |
| Owner | Company Name on File |
| Last Sale | $9,250,000 (Sep 2014) |
| Tax Bill | $123,950 (2025) |
| Flood Zone | Zone X (minimal risk) |
| APN | 070-032-040 |
| Primary APN | 070-032-040 |
|---|
| Bedrooms | 5 Beds |
|---|---|
| Full Baths | 8.5 Baths |
| Half Baths | 1 Half Bath |
| Total Rooms | 18 Rooms |
| Stories | 2 Stories |
| Building Area | 11,700 sqft Living Area |
| 1st Floor Area | 4,580 sqft |
| 2nd Floor Area | 2,540 sqft |
| Basement Area | 4,580 sqft |
| Finished Basement | 4,580 sqft |
| Family Room | Family Room |
| Study | Study |
| Fireplaces | 1 Fireplace |
| Fireplace | Fireplace |
| Year Built | Built 2004 |
|---|---|
| Effective Year Built | Effective 2004 |
| Lot Area | 46,224 sqft |
| Lot Dimensions | 215 ft deep x 215 ft wide |
| Garage Area | 800 sqft |
| Parking Spaces | 3 Parking Spaces |
| Cooling System | Central |
|---|---|
| Heating System | Central |
| Street Address | 291 POLHEMUS AVE |
|---|---|
| City | ATHERTON |
| State | CA |
| Zip | 94027-5456 |
| Property Category | Residential |
| Property Type | Residential > Single Family > Home |
| Local Zoning Code | R1001A |
| Legal Description | LOT 6 VARNEY SUBDIVISION RSM 44/20 TOWN OF ATHERTON |
| Legal Subdivision | VARNEY SUBDIVISION |
| Legal Lot Number | 6 |
| Jurisdiction | SAN MATEO CA |
| Township / Civil Division | SAN MATEO |
| Census Block Group | 3 |
| Census Block | 3003 |
| Census Tract | 611400 |
Source: San Mateo County records · APN 070-032-040
Assessment roll updated July 15, 2026 · Last verified July 2026
Owner names and exact recorded amounts shown locked on this page are available instantly with a free trial.
| Owner of Record | Company Name on File |
|---|---|
| Mailing Address | 5150 EL CAMINO REAL, D22, LOS ALTOS, CA 94022-1561 |
| Owner Type | Company |
| Vesting | Company |
| Deed Names | Verified Name on Deed |
|---|---|
| Last Sale | Sep 19, 2014 · Amount on Record |
| Deed Sale | Sep 19, 2014 · Amount on Record |
| Prior Sale | Dec 17, 2004 · Amount on Record |
| Deed Document Number | 201484862 |
| Prior Transfer Date | Mar 15, 2004 |
| Prior Transfer Doc | 0000080712 |
| Record Updated | Sep 20, 2026 |
Source: San Mateo County records · Assessment roll updated July 15, 2026 · Last verified July 2026
| Type | Name |
|---|---|
| State | California |
| Municipality | Atherton Town |
| County | San Mateo County |
| Elementary School District | Las Lomitas Elementary School District (KG - 08) |
| Secondary School District | Sequoia Union High School District (09 - 12) |
Assessed value is set for property tax purposes and is not a market price estimate.
| Year | Tax Bill | Assessed Value |
|---|---|---|
| 2026 | $11,395,226 (+2%) Land $6,178,470 Building $5,216,756 | |
| 2025 | $123,950.00 (+2.84%) | $11,171,792 (+4.04%) Land $6,057,324 Building $5,114,468 |
| 2023 | $120,532.00 (+2.83%) | $10,737,979 Land $5,822,111 Building $4,915,868 |
| 2022 | $117,217.00 |
Source: FEMA National Flood Hazard Layer, San Mateo County (06081C), as of September 10, 2026 · FEMA OpenFEMA NFIP redacted claims and policies, census block group 060816114003, as of September 2026 · USDA Forest Service Wildfire Risk to Communities, 2nd edition, as of 2020 · Last verified October 2026
| FEMA Flood Zone | Zone X minimal risk |
|---|---|
| Flood Insurance Requirement | Not required lenders may require it |
| Flood Insurance Cost | Premium on Record median of 10 policies |
| Nearby Flood Policies | 10 in force |
| Nearby Flood Claims | 1 (2022) |
| Claims Outside the SFHA | 1 of 1 |
| Most Recent Claim | Dec 2022 · Severe Winter Storms, Flooding, Landslides, And Mudslides |
| Wildfire Risk | Low lower than 97% of the US · lower than 97.8% of California |
|---|---|
| Wildfire Likelihood | Under 0.01% annual chance |
| Exposure | None beyond ember reach |
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: FCC Broadband Data Collection as of December 31, 2025 · Last verified October 2026
| Provider | Max Down / Up (Mbps) |
|---|---|
| Race Telecommunications 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 |
| Verizon Fixed Wireless | 300 / 20 |
May also be available: Etheric Communications, LLC..
Based on FCC filings for 136 locations within half a mile of this property.
Source: EPA Safe Drinking Water Information System, water system CA4110006, as of 2026 Q3 · EPA water system boundaries as of March 2026 · Last verified October 2026
| Water System | CALIFORNIA WATER SERVICE - BEAR GULCH private · serves 60,382 people |
|---|---|
| Water Source | Surface water |
| Last State Inspection | Feb 2025 |
| Lead | 4 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 as reported to EPA, not water tested at this address; lead at the tap also depends on the building's own pipes. The full violation and enforcement history is in the system's EPA record.
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