Atherton · Zoning · R-1A
Atherton R-1A zoning: height, setbacks and lot size
In Atherton's R-1A zone, generally buildings can be up to 30 ft tall and the front setback is 60 ft, with the conditions listed below (Atherton code, read October 2026).
Key points
- Maximum building height: 30 ft (may be increased up to 34 ft for main buildings (28 ft for sidewalls and columns); sidewalls and columns otherwise limited to 22 ft)
- Minimum front setback: 60 ft (Main building, interior, and corner lots.)
- Minimum rear setback: 60 ft (Main building, interior, and corner lots.)
- Maximum floor area ratio (FAR): 18% (Lots of 43,560 sq ft (one acre) or more; smaller lots use a formula)
R-1A (Residential District R-1A) is a zoning district in Atherton. Every value below was read from the Atherton Municipal Code and links to its section (read October 2026). State laws such as the ADU and SB 9 rules can allow more on a residential lot. General information, not legal advice — read the code text and check with the city before you build.
Development standards in R-1A
The general rule for a typical lot in this zone. Zoning tables often attach notes, such as rules for corner lots, lots next to a residential zone, or new subdivisions only. Open “code text” under a value to see the table cell or sentence it was read from.
| Maximum building height | 30 ft Applies: may be increased up to 34 ft for main buildings (28 ft for sidewalls and columns); sidewalls and columns otherwise limited to 22 ft § 17.32.040 · code textThe standard maximum height for main buildings shall be thirty feet; provided, that vertical sidewalls and columns may not exceed twenty-two feet; and provided further, that these standard maximum heights may be increased, but in no event to exceed thirty-four feet for main buildings nor to exceed twenty-eight feet for vertical sidewalls and columns, as follows: |
|---|---|
| Minimum front setback | 60 ft Applies: Main building, interior, and corner lots. § 17.32.040 · code textMain building, interior, and corner lots: sixty feet minimum; provided, however, on lots of record prior to adoption of Ordinance No. 146 (April 16, 1946) with a depth of less than two hundred feet, the front and rear yards shall each be thirty percent of the lot depth with a minimum of thirty feet; provided further, where main building heights are between thirty feet and thirty-four feet, the front and rear yards shall be increased by a ratio of five feet for each one-foot increase in height. |
| Minimum rear setback | 60 ft Applies: Main building, interior, and corner lots. § 17.32.040 · code textMain building, interior, and corner lots: sixty feet minimum; provided, however, on lots of record prior to adoption of Ordinance No. 146 (April 16, 1946) with a depth of less than two hundred feet, the front and rear yards shall each be thirty percent of the lot depth with a minimum of thirty feet; provided further, where main building heights are between thirty feet and thirty-four feet, the front and rear yards shall be increased by a ratio of five feet for each one-foot increase in height. |
| Maximum floor area ratio (FAR) | 18% Applies: Lots of 43,560 sq ft (one acre) or more; smaller lots use a formula § 17.32.040 · code textThe maximum floor area ratio shall be eighteen percent of the lot size except for those lots smaller than forty-three thousand five hundred sixty square feet (one acre), which shall be determined by the following equation: |
When a different number applies
The code sets other values for particular lots, buildings or locations in R-1A:
- Maximum building height: 34 ft — Upon approval of a special structure permit. § 17.32.040
- Minimum front setback: 30% of lot depth, min 30 ft — Lots of record before April 16, 1946, with depth less than 200 ft. § 17.32.040
- Minimum rear setback: 30% of lot depth, min 30 ft — Lots of record before April 16, 1946, with depth less than 200 ft. § 17.32.040
- Maximum floor area ratio (FAR): Floor area = (lot size × 0.163) + 726 sq ft, minimum 2,250 sq ft — Lots smaller than 43,560 sq ft (one acre). § 17.32.040
Not on this page
We did not find a general stories, side setback, lot size, lot coverage, density limit for R-1A in the zoning tables we read. The code may still set one elsewhere — check the Atherton Municipal Code.
Other Atherton zoning districts
Who this affects
Frequently asked questions
What is the maximum building height in Atherton's R-1A zone?
30 ft (may be increased up to 34 ft for main buildings (28 ft for sidewalls and columns); sidewalls and columns otherwise limited to 22 ft) — Atherton Municipal Code § 17.32.040.
What is the minimum front setback in Atherton's R-1A zone?
60 ft (main building, interior, and corner lots) — Atherton Municipal Code § 17.32.040.
What is the minimum rear setback in Atherton's R-1A zone?
60 ft (main building, interior, and corner lots) — Atherton Municipal Code § 17.32.040.
What is the maximum floor area ratio (far) in Atherton's R-1A zone?
18% (lots of 43,560 sq ft (one acre) or more; smaller lots use a formula) — Atherton Municipal Code § 17.32.040.
General information, not legal advice.
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