San Mateo County property record for 229 Polhemus Ave, Atherton, CA 94027
| Property Type | Single Family Home |
|---|---|
| Details | 2124 bd · 8.5 ba · 10,433 sqft · built 1930 |
| Lot Size | 2.39 acres (104,159 sqft) |
| Owner | Company Name on Record |
| Last Sale | $33,900,000 (Jul 2024) |
| Tax Bill | $372,177 (2025) |
| Flood Zone | Zone X (minimal risk) |
| APN | 070-040-110 |
| Primary APN | 070-040-110 |
|---|---|
| Alternative APN |
|
| Bedrooms | 2124 Beds |
|---|---|
| Full Baths | 8.5 Baths |
| Half Baths | 9 Half Baths |
| Total Rooms | 2084 Rooms |
| Stories | 3 Stories |
| Building Area | 10,433 sqft Living Area |
| 1st Floor Area | 6,049 sqft |
| 2nd Floor Area | 3,448 sqft |
| Basement Area | 1,081 sqft |
| Family Room | Family Room |
| Study | Study |
| Fireplaces | 5 Fireplaces |
| Fireplace | Fireplace |
| Year Built | Built 1930 |
|---|---|
| Effective Year Built | Effective 1930 |
| Lot Area | 104,159 sqft |
| Garage Area | 790 sqft |
| Parking Spaces | 3 Parking Spaces |
| Total Buildings | 2 Buildings |
| Cooling System | Central |
|---|---|
| Heating System | Central |
| Old Parcel Number | 070040110 |
|---|---|
| Street Address | 229 POLHEMUS AVE |
| City | ATHERTON |
| State | CA |
| Zip | 94027-5442 |
| Property Category | Residential |
| Property Type | Residential > Single Family > Home |
| Local Zoning Code | R1001A |
| Legal Description | PTN LOT 9 STERN OAKS RSM 36/19 TOWN OF ATHERTON |
| Legal Subdivision | STERN OAKS |
| Legal Lot Number | 9 |
| Jurisdiction | SAN MATEO CA |
| Township / Civil Division | SAN MATEO |
| Census Block Group | 3 |
| Census Block | 3003 |
| Census Tract | 611400 |
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 | Company Name on Record |
|---|---|
| Mailing Address | 1801 PAGE MILL RD, PALO ALTO, CA 94304-1216 |
| Owner Type | Company |
| Vesting | Limited Liability Company |
| Deed Names | Name on Deed |
|---|---|
| Last Sale | Jul 3, 2024 · Amount on Record |
| Deed Sale | Jul 3, 2024 · Amount on Record |
| Prior Sale | Jun 4, 2004 · Amount on Record |
| Deed Document Number | 202435434 |
| Prior Transfer Date | Mar 27, 2008 |
| Prior Transfer Doc | 0000044518 |
| Record Updated | Sep 20, 2026 |
Source: San Mateo County assessment roll, as of July 15, 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) |
| Year | Tax Bill | Assessed Value |
|---|---|---|
| 2026 | $34,578,000 (+2%) Land $20,802,900 Building $13,775,100 | |
| 2025 | $372,177.00 (+81.92%) | $33,900,000 (+87.63%) Land $18,750,000 Building $15,150,000 |
| 2024 | $204,579.00 (+1.57%) | |
| 2023 | $201,423.00 (+2.85%) | $18,067,211 Land $15,032,465 Building $3,034,746 |
| 2022 | $195,849.00 |
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 |
| 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 |
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 | Low lower than 96% of the US · lower than 97.4% of California |
|---|---|
| Wildfire Likelihood | Under 0.01% annual chance |
| Exposure | None beyond 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 - BEAR GULCH private · serves 60,382 people · EPA ID CA4110006 |
|---|---|
| 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, 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 160 locations within half a mile, as of December 31, 2025
| Provider | Max Down / Up (Mbps) |
|---|---|
| Race Communications Fiber | 10,000 / 10,000 |
| AT&T Fiber · Fixed Wireless in parts of the area | 5,000 / 5,000 |
| Xfinity Cable | 2,000 / 250 |
May also be available: Etheric Networks, Verizon.
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