Owner Occupancy. Prior to issuance of a building permit establishing an ADU, the owner shall sign and record as a deed restriction in the county auditor's office a certification by the owner under oath in a form prescribed by the city that one of the dwelling units is and will continue to be occupied by the owner of the property as the owner's principal and permanent residence for as long as the other unit is being rented or otherwise occupied. The owner shall maintain residency for at least six months out of the year, and at no time receive rent for, or otherwise allow to be occupied, the owner-occupied unit if absent for the remainder of the year(s). Sale or ownership of such unit separate from the primary residential unit is prohibited.