Atherton Real Estate & Zoning Glossary
An authoritative glossary defining municipal codes, land division terms, and architectural concepts specific to 94027.
Floor Area Ratio (FAR)
The mathematical ratio of total allowable above-grade building square footage relative to the net parcel area. In Atherton's R1-A zone, base main-house FAR is set at 18%.
R1-A Single-Family Zoning
The primary municipal land classification in Atherton restricting land use strictly to single-family residential compounds on minimum 1.0-acre parcels.
Heritage Tree Preservation (Chapter 12.16)
Town Ordinance governing native Quercus agrifolia (Coast Live Oak) and Sequoia sempervirens (Coast Redwood) with trunks measuring over designated diameter thresholds.
Accessory Dwelling Unit (ADU)
A secondary residential structure on a lot (guest house or caretaker quarters) subject to Atherton maximum square footage limits and independent utility requirements.
Front / Side Yard Setback Envelope
Mandatory clear distances measured from property boundaries within which permanent structural walls cannot be constructed (60 ft front, 30 ft sides in Atherton).
Subterranean Basement Exemption
Square footage fully subterranean below finished grade that does not count toward maximum allowable main house Floor Area Ratio.