Section 197A.425 - Accessory dwelling units(1)(a) A city with a population greater than 2,500 or a county with a population greater than 15,000 shall allow in areas within the urban growth boundary that are zoned for detached single-family dwellings the development of at least one accessory dwelling unit for each detached single-family dwelling, subject to reasonable local regulations relating to siting and design.(b) As used in this subsection:(A) "Accessory dwelling unit" means an interior, attached or detached residential structure that is used in connection with or that is accessory to a single-family dwelling.(B) "Reasonable local regulations relating to siting and design" does not include owner-occupancy requirements of either the primary or accessory structure or requirements to construct additional off-street parking.(2) Subsection (1) of this section does not prohibit local governments from regulating vacation occupancies, as defined in ORS 90.100, to require owner-occupancy or off-street parking.Formerly subsections (5) and (6) of 197.312