San Francisco Zoning, Planning & Building Codes

The San Francisco Planning Code governs how land may be used across the city — what can be built, where, and at what density — while the San Francisco Building Code governs how it is constructed. Land use is organized into zoning districts: RH (Residential, House), RM (Residential, Mixed), RC (Residential-Commercial) and the various NC (Neighborhood Commercial) districts. Sorting out which district applies to a parcel, and what it allows, is exactly the kind of question GoCodebook answers with citations.

San Francisco layers its own rules on top of the statewide California Building Standards Code and state housing laws. Recent density-exception ordinances now allow up to four units per lot (and up to six on corner lots) in many RH districts, and the city runs its own Accessory Dwelling Unit (ADU) program under the Planning Code. Because outcomes depend on the specific district, lot and building age, a plain-English, cited answer saves time before you file.

San Francisco's residential districts run from RH-1 (one house per lot) and RH-1(D) (detached, with side yards) through RH-2 and RH-3 (two and three units), up to RM districts that mix houses and apartments and RC and NC districts that combine residential with ground-floor commercial uses.

Each district sets its own controls on density, height, bulk, setbacks and permitted uses. To see where the city has detailed coverage, check our coverage page, and compare neighboring peninsula rules in Palo Alto or Cupertino.

Beyond the use district, every parcel also carries a height and bulk designation — written like 40-X. The two parts control the building envelope:

• Height limit — the number is the maximum height in feet (e.g. 40 in 40-X; common limits include 40, 65 and 105 ft).
• Bulk district — the letter limits a building's plan dimensions and is meant to break up massing. X means no bulk controls; letters such as A–G cap maximum length and diagonal dimension above a certain height.

A 2023 density-exception ordinance allows up to four units on most lots — and up to six on corner lots — in many RH districts, layered on top of state density law. What a specific parcel allows still depends on its district, height/bulk and lot.

San Francisco is known for a discretionary process. Many projects are not approved purely over the counter: a use may require conditional use (CU) authorization from the Planning Commission, and most residential building permits trigger Section 311 neighborhood notification, during which any member of the public can request discretionary review (DR) of the project before the Commission.

Because any neighbor can file a discretionary review during the Section 311 window, a permit that looks code-compliant can still face a hearing — timelines in San Francisco often hinge on this step.

Construction permits are issued and inspected by the Department of Building Inspection (DBI), which enforces the San Francisco Building, Housing and related codes — themselves amendments to the statewide California Building Code and Residential Code. Most projects move through Planning review for zoning compliance first, then DBI for the building permit and inspections.

A change of use — for example, converting commercial space to residential, or legalizing a unit — often requires both Planning sign-off and a DBI permit. DBI also handles housing-code enforcement and habitability complaints. Browse the full set of statewide model codes on our California Building Standards Code hub.

San Francisco has its own Rent Ordinance, administered by the SF Rent Board. Whether a unit is rent-controlled on price turns largely on the building's age, while just-cause eviction protections reach more broadly.

The key rent-control question is the building's age — a first certificate of occupancy before June 13, 1979 is the classic trigger for price controls. This local ordinance is stricter than, and runs alongside, the statewide AB 1482 cap — see our rent control overview.

The city also runs a local ADU program under the Planning Code that lets owners add accessory dwelling units to existing residential buildings, subject to its own controls. Because ADU and rent-control coverage both hinge on the building's age, type and history, the safest move is to check the specific property. Compare how rent-controlled Los Angeles handles similar questions.