Kern County, CA Accessory Structures: ADU Rules (2026)

Per Kern County Code of Ordinances Title 19 Zoning, Chapter 19.90 (Accessory Dwelling Units), Section 19.90.030 sets out the development standards in unincorporated Kern County. Only one ADU may be created per legal lot, and the lot must contain no other dwellings besides the principal dwelling. Minimum lot size is 7,500 net square feet if served by both community water and public sewer, one-half net acre if served by community water and a private septic system, or one net acre if served by neither. The principal dwelling must contain at least 1,200 gross square feet. For an attached or interior-conversion ADU, the maximum floor area is 1,200 square feet or 50 percent of the principal dwelling's floor space, whichever is less; for a detached ADU the maximum is 1,200 square feet. The ADU must have separate kitchen and bathroom facilities and a separate entrance. Either the principal dwelling or the ADU must be owner-occupied, and the ADU must comply with the front-yard, rear-yard, side-yard, distance-between-structures, and height standards of the underlying zoning district, but is excluded from minimum-lot-area-per-dwelling-unit standards.