Your architect sketches the new front of the building flush with the sidewalk, the way the corner building two doors down sits. The planner reviewing it disagrees, and points at the house next door — the one with the deep planted strip out front. Somewhere between those two buildings is a number you are now required to match, and in San Francisco's mixed residential districts it is not the number most people expect.
RM-2 is the Residential, Mixed District, Moderate Density — the same house-and-apartment mix as RM-1, at higher unit density (§ 201, § 209.2). Your front setback is copied from your neighbours and capped at 10 feet — or 15 feet where most of the block already has that (§ 132). The rear 30% of your lot depth stays open.
Key numbers for an RM-2 lot
| What | RM-2 standard | Source |
|---|---|---|
| District type | Residential, Mixed District, Moderate Density | § 201 |
| Rear yard | 30% of lot depth, never less than 15 feet | Table 209.2 |
| Side yard | Not required | Table 209.2 |
| Front setback, normal maximum | 10 feet from the property line | § 132 |
| Front setback, deep-block maximum | 15 feet, where more than 75% of the block face is set back 15 feet or more and both neighbours are too | § 132 |
| Lot with only one adjacent building | Half that building's front setback | § 132 |
| Planting in the front setback | At least 20% unpaved and devoted to plant material | § 132 |
| Height | Set by the Height and Bulk map, plus height sculpting on alleys | Table 209.2 |
What separates RM-2 from RM-1 and RM-3
All four RM districts are built on the same idea: blocks "characterized by a mixture of houses and apartment buildings," at scales that respect San Francisco's traditional lot patterns (§ 209.2). What changes between them is intensity. The code's description of RM-2:
These Districts are generally similar to RM-1 Districts, but the overall density of units is greater and the mixture of building types and unit sizes is more pronounced.
Two practical consequences follow. Building widths and scales stay moderate and considerable outdoor space remains — but the code explicitly warns that the higher permitted unit density "requires careful design of new structures in order to provide adequate amenities for the residents." And where shops and services appear, they tend to serve a wider area than RM-1's do.
Step up again to RM-3 and the character changes properly: predominantly apartment buildings of six, eight, ten or more units, many exceeding 40 feet in height. RM-3 and RM-4 also get a smaller required rear yard, 25% of lot depth, against RM-2's 30%.
The front setback is a copy of your neighbours
This is the rule that catches out owners and designers alike. There is no fixed front setback in RM-2. The code sets it by looking at what is already there (§ 132):
- Two neighbours with setbacks: you must set back at least as far as the adjacent building with the shortest front setback.
- Only one adjacent building: your required setback is half that building's.
- Corner lots: you elect which street or alley is your front, and the setback along it is half the adjacent building's.
- A neighbour that fronts on a different street is disregarded — you match the building on your opposite side instead.
- A neighbour in a commercial, industrial or public district is likewise disregarded; you match the nearest building that is in a house or mixed residential district.
- Vacant land in between: a building separated from you by undeveloped lots is still treated as "adjacent" if the gap is 50 feet or less. Beyond that, it is not.
Setbacks are measured horizontally from the property line to the closest building wall, ignoring projections, decks and garage structures.
The cap. The required front setback can never exceed 10 feet — with one exception. Where more than 75% of the properties on your block face are set back 15 feet or more, and both parcels next to you are as well, the maximum rises to 15 feet.
What has to live in that setback — and what may not
Once a front setback is required, it is not simply spare ground. At least 20% of it must remain unpaved and devoted to plant material, using climate-appropriate planting, and the whole area must be landscaped and meet the city's water use requirements. Only the obstructions the code specifically permits may sit there, and no car, trailer or boat may be parked or stored in it.
The landscaping duty is triggered by more than new construction: adding a dwelling unit, a garage or extra parking, any addition increasing gross floor area by 20% or more, a residential merger, or paving more than 200 square feet of the front setback all bring it into play.
What this article does not cover
These sections set the district's character and its setback rules. They do not tell you how many units your particular lot may hold, your Height and Bulk designation, or your parking requirements — and the floor area ratio limit for RM districts must be read from the district's own zoning control table rather than assumed (§ 124). Accessory dwelling units are governed by California state law alongside the local code. For the wider local picture, start at the San Francisco jurisdiction page and confirm your district and any overlay on the official sectional zoning maps.
