Montebello, CA Accessory Structures: ADU Owner Occupancy (2026)

Montebello Municipal Code Section 17.10.280(C) lists twenty-two development standards that apply to any accessory dwelling unit built in conjunction with a single-family home in the R-1 or R-A zones. Item 21 is an owner-occupancy condition: whoever holds at least a fifty percent ownership interest in the property must use either the primary dwelling or the accessory dwelling as their principal, full-time residence. The rule targets absentee-landlord conversions, keeping at least half the ownership tied to someone who actually lives on site in one of the two units, rather than renting out both the main house and the accessory unit to different tenants while the owner lives elsewhere.

Item 22 reinforces the same owner-occupancy structure from a different angle by prohibiting the accessory dwelling unit from being owned or sold separately from the primary dwelling unit, so a property owner cannot subdivide title and create two separately marketable homes on one lot. Together the two standards sit inside the same subsection that also caps the accessory unit's size, sets its minimum ten-foot setback from the primary home, and requires matching exterior architecture, so a homeowner evaluating an ADU project in Montebello needs to satisfy the occupancy condition alongside the physical design standards, not as a separate permit step.

An application that does not comply with subsection C, including the occupancy standard, can be appealed to the city manager under subsection F, though that appeal is limited to compliance review without a public hearing.