California counties
California county zoning & codes
Counties regulate zoning and building in unincorporated areas. GoCodebook covers 58 California counties — find yours below, or ask about an address.
City or county — which rulebook?
A great deal of California sits outside any city's limits, and on that land the county is the planning department. Getting this wrong means reading the wrong code from the start.
The mailing address lies
A parcel can have a city's name and ZIP code and still sit outside its limits. Postal geography and jurisdictional boundaries are different things, and only one of them decides your code.
The county is the planning authority
On unincorporated land the county's zoning ordinance controls use, density and setbacks, and the county issues the permits — the nearby city has no say.
Rural standards differ in kind
County codes deal with things city codes rarely touch: agricultural and resource zoning, minimum parcel sizes measured in acres, septic and well requirements, and access on private roads.
Overlays bite harder out here
Fire-severity zones, hillside and grading rules, flood and coastal overlays, and Williamson Act contracts routinely govern unincorporated parcels — often more than the base zoning does.
Inside city limits? Use the city directory instead, or read either code verbatim in the Code Library.
All counties
Common questions
How do I tell whether my property is in a city or unincorporated?
The mailing address won't tell you — a parcel can carry a city's name while sitting outside its boundary. The reliable checks are the county assessor's parcel record or the county's GIS map, both of which show the jurisdiction for the parcel. Asking about the specific address here resolves it too.
Does the county code apply inside city limits?
Generally no. Inside an incorporated city, that city's zoning and building code governs. The county still runs services that cross boundaries — assessor records, health permits, some environmental review — but land-use authority belongs to the city.
Does Title 24 apply in unincorporated areas?
Yes. The California Building Standards Code applies statewide regardless of jurisdiction. What changes between a city and a county is the zoning layer and any local amendments each has adopted on top of the state code.
Why is San Francisco listed as both a city and a county?
San Francisco is a consolidated city and county — one government exercising both sets of powers, with a single code. It's the only one in California, which is why the county count reads differently depending on how it's grouped.