Kern County, CA Accessory Structures: ADU Rules (2026)
ADU rules in Kern County, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Code Section
- Kern County Code § 19.90.030
- Max ADU size (detached)
- 1,200 sq ft
- Min lot size (water + sewer)
- 7,500 net sq ft
- Min principal dwelling size
- 1,200 sq ft gross
- ADUs allowed per lot
- 1
Summary
Kern County Zoning Ordinance Chapter 19.90 allows one accessory dwelling unit per legal lot, capped at 1,200 square feet, subject to minimum lot size and zoning district setbacks.
No accessory dwelling unit may be established unless it complies with the following standards: The lot upon which the accessory dwelling unit is to be established shall contain no other dwellings except for the principal dwelling... a minimum of seven thousand five hundred (7,500) net square feet if the lot is served by both a community water supply and public sewer... Only one (1) accessory dwelling unit may be created per legal lot.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 59 Update 1).
Full Breakdown
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.
Violations & Fines
Establishing or expanding an ADU outside Chapter 19.90 standards is a zoning violation. Under Title 19, zoning violations are misdemeanors and may also be abated as public nuisances; the county can require removal, withhold permits, and assess civil penalties through code enforcement.
Frequently Asked Questions
How many ADUs can I build on my Kern County property?
Does my Kern County ADU have to meet the same setbacks as the main house?
Do I have to live on the property if I build an ADU in unincorporated Kern County?
Sources & Official References
Other rules in Kern County
How Kern County compares: Easiest Cities to Build an ADU·California rules heatmap·Compare Kern County to another location·View the California accessory structures overview
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