San Mateo · Zoning · R1-A
San Mateo R1-A zoning: height, setbacks and lot size
In San Mateo's R1-A zone, generally buildings can be up to 32 ft tall and the front setback is 25 ft, with the conditions listed below (San Mateo code, read October 2026).
Key points
- Maximum building height: 32 ft (Measured from existing grade to the highest point of the roof; 24 ft to the building plate line.)
- Minimum front setback: 25 ft
- Minimum side setback: 7 ft
- Minimum rear setback: 15 ft (25 ft for new construction above a single story)
- Maximum floor area ratio (FAR): 0.4 for parcels of less than or equal to 10,000 square feet plus 0.2 for additional parcel area over 10,000 square feet (No more than 6,000 sq ft of total floor area per parcel in residential use.)
R1-A is a zoning district in San Mateo. Every value below was read from the San Mateo 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 R1-A
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 | 32 ft Applies: Measured from existing grade to the highest point of the roof; 24 ft to the building plate line. § 27.18.050 · code textThe maximum height of structures shall be 24 feet measured from existing grade to the building plate line and 32 feet measured from the existing grade to the highest point of the roof. |
|---|---|
| Minimum front setback | 25 ft § 27.18.070 · code textA front yard not less than twenty-five (25) feet in an R1-A district and not less than fifteen (15) feet in an R1-B or R1-C district shall be provided. |
| Minimum side setback | 7 ft § 27.18.080 · code textInterior side yards not less than seven (7) feet in an R1-A district and not less than five (5) feet in an R1-B or R1-C district shall be provided. |
| Minimum rear setback | 15 ft Applies: 25 ft for new construction above a single story § 27.18.090 · code textA rear yard of not less than fifteen (15) feet shall be provided; a rear yard not less than twenty-five (25) feet shall be provided for new construction above a single story. |
| Maximum floor area ratio (FAR) | 0.4 for parcels of less than or equal to 10,000 square feet plus 0.2 for additional parcel area over 10,000 square feet Applies: No more than 6,000 sq ft of total floor area per parcel in residential use. § 27.18.060 · code textTable row “R1-A”, column “Maximum Floor Area Ratio”: 0.4 for parcels of less than or equal to 10,000 square feet plus 0.2 for additional parcel area over 10,000 square feet. |
When a different number applies
The code sets other values for particular lots, buildings or locations in R1-A:
- Maximum building height: 24 ft — measured from existing grade to the building plate line § 27.18.050
- Minimum rear setback: 25 ft — for new construction above a single story § 27.18.090
Not on this page
We did not find a general stories, lot size, lot coverage, density limit for R1-A in the zoning tables we read. The code may still set one elsewhere — check the San Mateo Municipal Code.
Other San Mateo zoning districts
Who this affects
Frequently asked questions
What is the maximum building height in San Mateo's R1-A zone?
32 ft (measured from existing grade to the highest point of the roof; 24 ft to the building plate line) — San Mateo Municipal Code § 27.18.050.
What is the minimum front setback in San Mateo's R1-A zone?
25 ft — San Mateo Municipal Code § 27.18.070.
What is the minimum side setback in San Mateo's R1-A zone?
7 ft — San Mateo Municipal Code § 27.18.080.
What is the minimum rear setback in San Mateo's R1-A zone?
15 ft (25 ft for new construction above a single story) — San Mateo Municipal Code § 27.18.090.
What is the maximum floor area ratio (far) in San Mateo's R1-A zone?
0.4 for parcels of less than or equal to 10,000 square feet plus 0.2 for additional parcel area over 10,000 square feet (no more than 6,000 sq ft of total floor area per parcel in residential use) — San Mateo Municipal Code § 27.18.060.
General information, not legal advice.
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