Millbrae · Zoning · R-3
Millbrae R-3 zoning: height, setbacks and lot size
In Millbrae's R-3 zone, generally buildings can be up to 40 ft tall, the front setback is 20 ft and the minimum lot size is 5,000 sq ft, with the conditions listed below (Millbrae code, read October 2026).
Key points
- Maximum building height: 40 ft
- Minimum front setback: 20 ft
- Minimum side setback: 10% of lot width, min 5 ft, max 20 ft (interior side yards add 2 ft beyond the 5 ft minimum for each 10 ft, or part, of building height over 24 ft)
- Minimum rear setback: 5 ft (Add 2 ft for each 10 ft, or part of 10 ft, that the building is taller than 24 ft.)
- Minimum lot size: 5,000 sq ft (Interior lots)
- Maximum lot coverage: 75%
- Maximum floor area ratio (FAR): No limit
R-3 (Multifamily Residential) is a zoning district in Millbrae. Every value below was read from the Millbrae 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-3
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 | 40 ft § 10.05.0820 · code textMaximum height of structures shall be forty feet. |
|---|---|
| Minimum front setback | 20 ft § 10.05.0820 · code textFront: twenty feet. |
| Minimum side setback | 10% of lot width, min 5 ft, max 20 ft Applies: interior side yards add 2 ft beyond the 5 ft minimum for each 10 ft, or part, of building height over 24 ft § 10.05.0820 · code textTen percent of lot width, but in no case less than five feet or more than twenty feet. |
| Minimum rear setback | 5 ft Applies: Add 2 ft for each 10 ft, or part of 10 ft, that the building is taller than 24 ft. § 10.05.0820 · code textRear: five feet minimum, plus two feet for each ten feet, or portion thereof, that the building exceeds twenty-four feet in height. |
| Minimum lot size | 5,000 sq ft Applies: Interior lots § 10.05.0820 · code textFive thousand square feet for interior lots. |
| Maximum lot coverage | 75% § 10.05.0820 · code textLot coverage: seventy-five percent. |
| Maximum floor area ratio (FAR) | No limit § 10.05.0820 · code textFloor area ratio (FAR): no limit. |
When a different number applies
The code sets other values for particular lots, buildings or locations in R-3:
- Minimum side setback: Additional 2 ft for each 10 ft, or portion thereof, above 24 ft building height — Interior side yards; building exceeds 24 feet in height § 10.05.0820
Not on this page
We did not find a general stories, density limit for R-3 in the zoning tables we read. The code may still set one elsewhere — check the Millbrae Municipal Code.
Other Millbrae zoning districts
Who this affects
Frequently asked questions
What is the maximum building height in Millbrae's R-3 zone?
40 ft — Millbrae Municipal Code § 10.05.0820.
What is the minimum front setback in Millbrae's R-3 zone?
20 ft — Millbrae Municipal Code § 10.05.0820.
What is the minimum side setback in Millbrae's R-3 zone?
10% of lot width, min 5 ft, max 20 ft (interior side yards add 2 ft beyond the 5 ft minimum for each 10 ft, or part, of building height over 24 ft) — Millbrae Municipal Code § 10.05.0820.
What is the minimum rear setback in Millbrae's R-3 zone?
5 ft (add 2 ft for each 10 ft, or part of 10 ft, that the building is taller than 24 ft) — Millbrae Municipal Code § 10.05.0820.
What is the minimum lot size in Millbrae's R-3 zone?
5,000 sq ft (interior lots) — Millbrae Municipal Code § 10.05.0820.
General information, not legal advice.
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