There are two answers here, and which one you need depends on whether you are building.
The Floor Area Ratio limits in Table 124 do not apply to homes. Planning Code Section 124(b) says so — and, since 2026, points at the section that does:
In R, RC, NC, and Mixed Use Districts, Floor Area Ratio limits shall not apply to Residential Uses. However, projects proposing new construction of a Dwelling Unit that would exceed the maximum dwelling unit size described in Section 207.10 may require Conditional Use authorization by the Planning Commission as set forth in Section 207.10.
— § 124(b), San Francisco Planning Code
RH-1, RH-2 and RH-3 are R Districts, so a dwelling in one of them is exempt from Table 124's limit. But since 12 January 2026 a different section caps the size of a home outright, and part of that cap is expressed as a ratio. Section 207.10 restricts an individual Dwelling Unit to 4,000 square feet of Gross Floor Area, or a Floor Area Ratio of 1.2:1, whichever is greater.
So "what is the maximum FAR for a house in San Francisco" no longer has the answer "there isn't one." For a new build it is 1.2:1, or 4,000 square feet — whichever gives you more.
Section 207.10: the cap that replaced the question
Ordinance 245-25 added Section 207.10, Maximum Dwelling Unit Size, effective 12 January 2026. It is the provision that gives San Francisco a residential floor-area figure again, and it is not in Table 124.
Any project that meets one or more of the criteria in subsection (b) shall be restricted to a maximum Dwelling Unit size of 4,000 square feet of Gross Floor Area or an equivalent Floor Area Ratio for any individual Dwelling Unit of 1.2:1, whichever is greater…
— § 207.10(c), San Francisco Planning Code
Who it applies to. Projects with a Development Application filed after 31 January 2026 that propose new dwelling units (including replacing a unit being demolished), the merger of two or more units, or a reduction in the number of units. An existing house nobody is altering is not caught by it.
The two figures, and which one wins. The cap is the greater of 4,000 square feet and a 1.2:1 ratio — so on a small lot the 4,000-square-foot figure is the one that governs, and on a large lot the ratio is. The two are equal at a lot of about 3,333 square feet; that arithmetic is ours, not the Code's.
Exceptions for multi-unit projects. A new-construction project of four to nine units may have one unit over 4,000 square feet; a project of ten or more may have up to 10% of its units over it.
Over the cap? That is not a prohibition. Section 207.10(d) treats a non-compliant project as one needing Conditional Use authorization from the Planning Commission, judged against the criteria in § 207.10(e) and § 303(c).
What counts toward Gross Floor Area. Section 207.10(f) uses the § 401 definition, excludes shared and common areas in multi-unit buildings and non-contiguous accessory storage — and includes every expansion permitted in the previous ten years, plus any construction done without a valid permit whenever it happened.
The basic FAR limits, and who they bind
Section 124 still sets a basic FAR for every district in Table 124, and those figures govern the uses that are subject to FAR. For the residential house districts the figure is 1.8 to 1:
| District | Basic Floor Area Ratio limit |
|---|---|
| RH-1(D), RH-1, RH-1(S), RH-2, RH-3 | 1.8 to 1 |
| RM-3 | 3.6 to 1 |
| RM-4 | 4.8 to 1 |
| C-3-S | 5.0 to 1 |
| C-3-O | 9.0 to 1 |
A figure sometimes quoted as San Francisco's residential FAR — 3.6 to 1 — belongs to the RM-3 row, a medium-density mixed district, not to the RH districts where most single-family homes sit.
Where 4.8:1 and 10.0:1 actually come from
Both figures are real, and both are commercial rules. Section 124(c) opens by naming the district it applies to:
In a C-2 District the basic floor area ratio limit shall be 4.8 to 1 for a lot which is nearer to an RM-4 or RC-4 District than to any other R District, and 10.0 to 1 for a lot which is nearer to a C-3 District than to any R District. The distance to the nearest R District or C-3 District shall be measured from the midpoint of the front line, or from a point directly across the street therefrom, whichever gives the greatest ratio.
— § 124(c), San Francisco Planning Code
The "nearer to an RM-4 or RC-4 District" test is a C-2 rule. It does not raise the FAR on a single-family lot in an RH district, because no FAR applies to that dwelling in the first place.
Section 124(e) is the same shape: the 5.0 to 1 figure for the Waterfront Special Use Districts applies "in any C District."
What actually limits the size of a house
Section 207.10 caps the unit. Everything else that shapes the building is dimensional, and is found by looking the parcel up rather than by reading one number off a table:
- Height. Section 260 measures height against the limit shown on the Zoning Map, and Section 261 adds further limits to dwellings in certain RH districts on top of whatever Article 2.5 sets.
- Rear yard. Section 134 sets the required rear yard in R, RC and NC Districts, written to protect the mid-block open space that runs behind a San Francisco block and to keep development at a scale appropriate to the district.
- Front setback. Section 132 sets front setbacks in RH, RTO and RM Districts by relating them to the existing setbacks of adjacent buildings, rather than to a fixed dimension.
- Lot width and area. Section 121's minimums apply to every property in the City, regardless of district, use, or whether the ownership is public or private.
- Density. Section 207 puts the permitted number of dwelling units in the Zoning Control Table for the district. Where no density limit is specified there, the Code says density is limited not by lot area but by the other requirements set out elsewhere in the Code — the height, yards and setbacks above.
Together those produce a buildable envelope. A FAR would have been a single ratio; this is a shape, and two lots in the same district can support very different houses.
What this means in practice
- Building a house in an RH district? Table 124's FAR is not your limit, but § 207.10 is: 4,000 square feet or 1.2:1, whichever is greater, then Conditional Use above that. Design to that cap plus the height and bulk district, the rear yard and the setbacks.
- Building something non-residential in an R district? The Table 124 figure for that district applies — 1.8 to 1 in the RH districts.
- On a C-2 lot? Then § 124(c)'s proximity test is the one to run, and it can reach 4.8 to 1 or 10.0 to 1.
Section 124(a) also notes that the Zoning Control Table for your district can specify a basic FAR, and Sections 125 through 128.1 add premiums and floor-area transfers. Confirm your district and any special use district with San Francisco Planning before you design to any figure on this page.
Code references: Sections 102, 123, 124 (including 124(b), 124(c) and 124(e)), 207.10 and 401, San Francisco Planning Code. Section 207.10 was added by Ordinance 245-25, approved 12 December 2025, effective 12 January 2026.
