Journal
An ADU can now be sold separately in San Diego County's unincorporated communities
Written by Zohra Azizi, CA DRE# 01992847 · Updated 2026-07-30
The County adopted AB 1033 in March 2026: an accessory dwelling unit in Fallbrook, Valley Center, Ramona and the rest of the unincorporated county can be converted to a condominium and sold on its own. What the ordinance actually allows, where it does not apply, and the parcel-level facts that decide whether a backcountry ADU pencils.
Can you sell an ADU separately from the main house in San Diego County?
San Diego County’s Board of Supervisors voted on March 4, 2026 to implement AB 1033, and since April 4, 2026 an accessory dwelling unit in the county’s unincorporated communities can be sold separately from the primary home through a condominium conversion.
The mechanics are real-property mechanics, not a shortcut: the conversion runs through the Subdivision Map Act and the Davis-Stirling common-interest framework, existing lienholders must consent, and the County publishes an ADU condo guidance checklist for determining whether a specific project qualifies. The Board also directed staff to develop first-time-homebuyer and owner-occupancy options, which went to the Planning Commission in June 2026 — the program is young and still moving.
Does the ADU separate-sale rule apply inside San Diego city limits?
The County of San Diego’s separate-sale ordinance covers only unincorporated territory — Fallbrook, Valley Center, Ramona and communities like them — while an address inside the city of San Diego, Escondido, Oceanside, Carlsbad or any other incorporated city follows that city’s own ADU rules.
AB 1033 is opt-in: a city has to pass its own ordinance before an ADU there can be sold separately, so the answer changes at the city line rather than the mailing address — and the map is moving. Escondido opted in with its June 2026 ADU ordinance overhaul, which makes ADU approval ministerial and allows separate sale under the state framework. The trap that runs through school districts runs through zoning too — a “Fallbrook” or “Escondido” mailing address does not say which jurisdiction governs the parcel. The planning department that issues the permit is the authority, and the same verify-the-actual-boundary habit serves buyers in both cases.
Do you have to live on the property to rent out an ADU in San Diego?
California law bars local agencies from imposing owner-occupancy requirements on accessory dwelling units — AB 976 made the prohibition permanent in October 2023 — so a San Diego ADU can be built and rented without the owner living in either unit.
One boundary survives: local agencies may still require rental terms of 30 days or longer, so an ADU is not automatically a short-term rental. Reading the owner-occupancy rule and the separate-sale ordinance together shows what changed in 2026: an ADU in the unincorporated county is no longer only a rental income stream — it is a unit that can eventually be sold on its own, which changes what the construction cost buys.
Why is the ADU math different in Fallbrook, Valley Center and Ramona?
Large unincorporated parcels in Fallbrook, Valley Center and Ramona clear the space constraints that pinch suburban ADUs, but the same parcels bring septic capacity, well yield and fire-zone insurance into the equation — costs that do not exist on a sewered city lot.
A septic system is sized to bedroom count, and an added dwelling can trigger an upgraded or second system; a shared well’s yield has to support the added household; and insuring a second structure in a fire hazard severity zone runs into the same narrowed market covered in the FAIR Plan explainer. None of these kills a project, and all of them are quantifiable before design money is spent. The Fallbrook, Valley Center and Ramona guides carry the parcel-level land-use picture.
How do you check what ADU rules apply to a specific San Diego parcel?
An ADU’s real constraints in San Diego County are parcel-level facts — jurisdiction, zoning, sewer or septic, fire hazard designation — and every one of them is checkable at the planning counter before any money is spent.
Establish the jurisdiction first, because it decides which ordinance governs and whether separate sale is even on the table. Then the parcel’s zoning layer, the wastewater answer, and the fire designation, in that order — each narrows the design space and the budget before an architect is engaged. For unincorporated parcels, the County’s ADU condo checklist states the separate-sale eligibility conditions in full.
Zoning and ADU standards are jurisdiction-specific and under active revision. Ordinance details above are as adopted by the County of San Diego on March 4, 2026 (effective April 4, 2026); the planning department for the parcel’s actual jurisdiction is the authority for any specific project.
Published 2026-07-30