National City, CA Accessory Structures: ADU Owner Occupancy (2026)

National City splits owner occupancy between two sections of the Land Use Code (Title 18). For a standard ADU, Section 18.30.380(G)(4) says owner occupancy of the primary unit or the ADU is not required. The owner can live elsewhere and rent both the house and the ADU, subject to the rental rules in the same subsection: the ADU can serve as a rental unit or be occupied by family members, guests or in-home health care providers at no cost, and neither the ADU nor the primary dwelling can be rented for less than 31 days.

A junior accessory dwelling unit under Section 18.30.390 works the other way. One JADU is permitted on a lot that includes a proposed or existing single-family dwelling, and the owner must occupy the single-family residence in which the JADU will be permitted. The owner can live in the remaining portion of the structure or in the newly created JADU. Owner-occupancy is not required when the owner is another governmental agency, land trust or housing organization.

The residence requirement is backed by paper. Before a building permit issues for a JADU, the record owner must enter into an agreement with the City in a form approved by the City Attorney. That agreement must state that the JADU may not be sold or conveyed separately from the primary dwelling, that it can be enforced against future purchasers, that the JADU will not be rented for less than 31 days, and that the record owner will reside on the premises. The City submits it to the County Recorder for recordation, and it runs with the land for the life of the JADU. The parallel agreement for a standard ADU under Section 18.30.380(G)(8) lists the no-separate-sale and 31-day terms but has no residence term.

A JADU must be at least 150 square feet and no more than 500 square feet, needs a separate exterior entry and a kitchen or efficiency kitchen, and staff act on the permit application within 60 days after a complete application is received.