Atherton R-1B zoning: height, setbacks and lot size

R-1B (Residential District R-1B) 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-1B

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	28 ft Applies: Main buildings § 17.33.040 · code text 1. Main buildings: twenty-eight feet; provided, that neither vertical side walls or columns exceed eighteen feet. End walls shall be perpendicular to the lot depth.
Minimum front setback	30 ft Applies: Main buildings, interior and corner lots § 17.33.040 · code text 1. Main buildings, interior and corner lots: thirty feet minimum; provided, however, on lots of record prior to adoption of Ordinance No. 277 (October 30, 1967) with a depth less than one hundred sixty feet, the front and rear yards shall each be eighteen percent of the lot depth with a minimum of twenty feet; and
Minimum rear setback	30 ft Applies: Main buildings, interior and corner lots § 17.33.040 · code text 1. Main buildings, interior and corner lots: thirty feet minimum; provided, however, on lots of record prior to adoption of Ordinance No. 277 (October 30, 1967) with a depth less than one hundred sixty feet, the front and rear yards shall each be eighteen percent of the lot depth with a minimum of twenty feet; and
Maximum floor area ratio (FAR)	18% Applies: Lots of 43,560 sq ft (one acre) or more; smaller lots use a formula § 17.33.040 · code text The 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-1B:

Minimum front setback: 18% of lot depth, min 20 ft — Lots of record prior to October 30, 1967, with depth less than 160 ft § 17.33.040
Minimum rear setback: 18% of lot depth, min 20 ft — Lots of record prior to October 30, 1967, with depth less than 160 ft § 17.33.040
Maximum floor area ratio (FAR): Floor area = (lot size × 0.165) + 1,500 sq ft — Lots smaller than 43,560 sq ft (one acre) § 17.33.040

Not on this page

We did not find a general stories, side setback, lot size, lot coverage, density limit for R-1B 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

HomeownersArchitects and designersDevelopersReal estate agents

Frequently asked questions

What is the maximum building height in Atherton's R-1B zone?

28 ft (main buildings) — Atherton Municipal Code § 17.33.040.

What is the minimum front setback in Atherton's R-1B zone?

30 ft (main buildings, interior and corner lots) — Atherton Municipal Code § 17.33.040.

What is the minimum rear setback in Atherton's R-1B zone?

30 ft (main buildings, interior and corner lots) — Atherton Municipal Code § 17.33.040.

What is the maximum floor area ratio (far) in Atherton's R-1B zone?

18% (lots of 43,560 sq ft (one acre) or more; smaller lots use a formula) — Atherton Municipal Code § 17.33.040.

General information, not legal advice.