Building permits, zoning and rural land rules across California

California has 0 counties classified as requiring no residential building permit, 3 with requirements only in some cases, and 55 requiring a residential building permit¹. These county counts concern unincorporated land; incorporated cities exercise their own building and zoning authority^8,9.

California's 2025 Building Standards Code applies to buildings and structures with permit applications dated January 1, 2026 or later¹⁰. California's owner-builder exemption concerns contractor licensing, and owner-builders must obtain building permits and pass inspections^5,6. Use the California owner-builder guide to explore that exemption, then ask the parcel's building official which building permits the proposed project needs^5,11.

California has 0 counties without county-wide zoning, and all 58 counties have county zoning¹. California also has 0 counties classified as having neither a residential building permit nor county-wide zoning¹.

California county and city legislative bodies can regulate land uses, building location and size, lot coverage, parking and setbacks through zoning ordinances⁹. Building setbacks, side and rear yards, and property-line requirements are generally reserved to local jurisdictions, subject to statutory exceptions¹². Before choosing rural land, ask the county planning office for the parcel's zoning district and the proposed dwelling's applicable land-use and setback requirements; inside city limits, ask the city planning office^9,12.

County offices issue septic permits in 55 California counties, while district authorities serve 3 counties¹. Named county agencies include Alameda County Department of Environmental Health and Butte County Environmental Health Division¹. The State Water Resources Control Board establishes the statewide onsite wastewater treatment system policy, and local agencies issue septic permits under that framework².

New and replacement systems follow applicable local permitting and design requirements; existing properly functioning systems have a separate policy category². Approved Local Agency Management Programs can tailor siting and design standards locally². Ask the parcel's local septic agency for its application, site-evaluation requirements and current septic permit fee; use the Water Board's regional jurisdiction page when the responsible office is unclear^2,13.

Humboldt County leads California's Bolthole Index at 60, followed by Mendocino County, Placer County and Shasta County at 56 each¹. Nevada County, Butte County, Lassen County and Del Norte County complete the leading group; all of these counties require residential building permits, have zoning and use county septic authorities¹.

The median county farmland value is $11,471 per acre, and the median county effective property tax rate is 0.7%, with a median county annual tax bill of $3,172¹. Inyo County has the lowest listed farmland value at $961 per acre, followed by Sierra County at $2,427¹. Use these county farmland values and tax medians as comparison measures, then request parcel-specific pricing and a tax estimate.

California well owners need local well permits before construction, modification or destruction, and water-well construction must be performed by a licensed well-drilling contractor⁷. DWR sets minimum well standards, while local enforcing agencies administer well permits and may adopt stricter standards¹⁴.

Parts of 45 California counties fall inside a special groundwater management regime, including actively managed, declining and adjudicated basins; a county-level designation does not identify the regime for every parcel¹⁵. Ask the local environmental health agency or water district which well ordinance applies and whether the parcel falls within a groundwater management area^7,15. For proposed access work within a state highway right of way, California requires a Caltrans encroachment permit from the appropriate District Encroachment Permits Office¹⁶.