San Mateo County property record for 290 Polhemus Ave, Atherton, CA 94027
| Property Type | Single Family Home |
|---|---|
| Details | 4 bd · 4 ba · 5,180 sqft · built 1942 |
| Lot Size | 5.3 acres (231,080 sqft) |
| Owner | 2 Company Names on File |
| Tax Bill | $10,170 (2025) |
| Flood Zone | Zone X (minimal risk) |
| APN | 070-012-180 |
| Primary APN | 070-012-180 |
|---|
| Bedrooms | 4 Beds |
|---|---|
| Full Baths | 4 Baths |
| Total Rooms | 12 Rooms |
| Stories | 1 Story |
| Building Area | 5,180 sqft Living Area |
| Gross Area | 5,680 sqft |
| 1st Floor Area | 4,760 sqft |
| Basement Area | 500 sqft |
| Family Room | Family Room |
| Study | Study |
| Year Built | Built 1942 |
|---|---|
| Effective Year Built | Effective 1942 |
| Lot Area | 231,080 sqft |
| Lot Dimensions | 501 ft deep x 461 ft wide |
| View / Lot | Corner |
| Garage Area | 780 sqft |
| Parking Spaces | 3 Parking Spaces |
| Cooling System | Central |
|---|---|
| Heating System | Central |
| Street Address | 290 POLHEMUS AVE |
|---|---|
| City | ATHERTON |
| State | CA |
| Zip | 94027-5455 |
| Property Category | Residential |
| Property Type | Residential > Single Family > Home |
| Local Zoning Code | R1001A |
| Legal Description | 5.307 AC MOL BEING SELY 501 FT OF LOT 53 POLHEMUS TRACT RSM 2/35 TOWN OF ATHERTON |
| Legal Subdivision | POLHEMUS TRACT |
| Legal Lot Number | 53 |
| Jurisdiction | SAN MATEO CA |
| Township / Civil Division | SAN MATEO |
| Census Block Group | 3 |
| Census Block | 3002 |
| Census Tract | 611400 |
Source: San Mateo County records · APN 070-012-180
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 | 2 Company Names on File |
|---|---|
| Mailing Address | PO BOX 7244, MENLO PARK, CA 94026-7244 |
| Owner Type | Company |
| Vesting | Life Tenant |
| Deed Names | 2 Verified Names on Deed |
|---|---|
| Last Transfer Date | Sep 15, 2016 |
| Transfer Doc | 0000094541 |
| 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 and assessed market value are set for property tax purposes and are not market price estimates.
| Year | Tax Bill | Assessed Value | Assessed Market Value |
|---|---|---|---|
| 2026 | $787,176 (+2.67%) Land $406,864 Building $380,312 | ||
| 2025 | $10,170.00 (+7.51%) | $766,742 (+8.72%) Land $398,887 Building $367,855 | |
| 2023 | $9,460.00 (+2.64%) | $705,252 Land $383,399 Building $321,853 | $7,928,100 |
| 2022 | $9,217.00 |
Source: FEMA National Flood Hazard Layer as of September 10, 2026 · FEMA NFIP claims and policies as of September 2026 · USDA Forest Service Wildfire Risk to Communities as of 2024 · 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 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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