United States · California
California regulations
Building codes, zoning, land use and housing law across California — statewide codes layered with the local zoning ordinances of 482 cities and 58 counties.
California Building Standards Code (Title 24)
All 13 parts — building, residential, electrical, mechanical, plumbing, energy, fire, CALGreen and more.
ExploreHousing & tenant law
Rent control, AB 1482, Costa-Hawkins, the Ellis Act, just-cause eviction, the statewide rent cap, SB 567 and ADU law.
ExploreCities (482)
Local zoning, planning and building-permit guides for California cities.
ExploreCounties (58)
Local zoning, planning and building-permit guides for California counties.
Explore540
Cities & counties
794
Codes & ordinances
289,000+
Code sections
13
Parts of Title 24
How the rules stack
No single document decides what you can build in California. Three layers apply to every parcel, and the answer usually lives where they meet.
State
Title 24 and the housing statutes
The Building Standards Code sets construction requirements statewide, and housing law sets floors cities can't go below — ADU rights, rent caps, eviction protections.
County
Unincorporated land
If a parcel sits outside any city's limits, the county's zoning and building code governs it — a different rulebook from the nearest city's.
City
Local zoning and planning
Inside city limits, the municipal code decides use, density, height, setbacks and parking. This is the layer that changes most at every jurisdiction line.
Start with a major city
San Francisco
San Francisco Planning Code, Building Code, zoning districts and permit pathways.
Los Angeles
Los Angeles zoning code (Chapters 1 & 1A), rent stabilization and building rules.
Cupertino
Cupertino Municipal Code Title 19 zoning and development standards.
Palo Alto
Palo Alto zoning (Title 18), master plan and precise plans.
Or find any of the 482 cities and 58 counties we cover.
Common questions
Does state law or my city's code control?
Both. Title 24 sets construction standards statewide, and state housing law sets minimums a city cannot undercut. Within that, the local zoning code decides what you may build and where. State language like "a city shall not require more than X" is a ceiling on the city — not the requirement itself.
How do I know whether I'm under a city or a county?
If the address is inside an incorporated city's limits, the city's code applies. Otherwise the parcel is unincorporated and the county's code applies — even when it has a city mailing address. Ask about the specific address if you're not sure.
Which edition of the building code applies to my project?
California publishes a new Title 24 edition on a three-year cycle; the 2025 edition takes effect January 1, 2026. Which edition governs generally follows the date your permit application is filed, so a project in progress may still be under the prior edition.
Is the actual code text available, or just summaries?
Both. Every guide here is written from the enacted text, and the Code Library holds the verbatim ordinances — 289,000+ sections — so you can read the controlling language yourself instead of taking a summary's word for it.
More answers on the questions page, or read the verbatim text in the Code Library.