Unincorporated San Diego County administers ADU permits through Planning & Development Services. The County publishes a generous standard-plan library and has issued AB 1033 condo-conversion guidance.
Detached ADU up to 1,200 sq ft. Attached ADU up to 50% of the single-family dwelling area, capped at 1,200 sq ft (with exceptions when the main home has more than one bedroom). JADUs up to 500 sq ft.
State guarantee: California requires every city to allow at least an 800 sq ft ADU exempt from local lot coverage, FAR, and front-setback rules.
Height baseline: 16 ft for detached, rising to 18 ft within ½ mile of major transit. Attached ADUs follow the primary home, capped at 25 ft.
Parking depends on the project and the County zoning package (PDS-PLN-611) plus applicable state exemptions. Confirm site-specific outcomes with PDS.
Property Summary Report via CitizenAccess; submittal checklist (PDS-658) plus PDS-441A walkthrough. Downloadable ~85% complete County Standard ADU plans are available for reuse.
State backstop: A complete ADU permit must receive a decision in 60 business days. If the city stalls past 30 business days, AB 253 lets you hire a certified private plan checker to force a 10-business-day decision.
The County’s trial ADU impact-fee waiver ran Jan 9, 2019 through Jan 9, 2024 — permits not issued by that date pay standard fees. Per state law, fees are waived under 750 sq ft.
SB 543: No impact fees on ADUs ≤750 sq ft. Above 750 sq ft, fees scale to the ratio of ADU size vs the main home.
Visit the official County of San Diego (Unincorporated) ADU page (link in hero) for current eligibility and downloads.
Standard ADUs in County of San Diego (Unincorporated): no owner-occupancy required (made permanent in 2023).
JADUs: limited to 500 sq ft of interior livable space within an existing single-family home. Owner occupancy is required only when sanitation facilities are shared with the main house. JADUs cannot be used as short-term rentals (AB 1154 / SB 543).
Sketch a floorplan, walk through it in 3D, and have our planners review it for size, height, and setback compliance before you submit to County of San Diego (Unincorporated).
Heads up: Local rules change frequently. This page summarizes publicly available state law (California Government Code §§ 66310–66342) and current local guidance for general planning purposes. Always confirm specifics with the County of San Diego (Unincorporated) planning desk before submitting plans. ADUMetrics does not provide legal advice.