Oregon Revised Statutes Revenue and Taxation § 310.160

(1) For purposes of determining whether the taxes on property to be imposed on any property exceed the limits imposed by section 11b, Article XI of the Oregon Constitution, the unit of property to be considered shall consist of all contiguous property within a single code area in the county under common ownership that is used and appraised for a single integrated purpose, whether or not that property is taxed as a single account or multiple accounts.

(2) In the case of real property that is specially assessed under ORS 308A.107, 308A.256, 308A.315 or 321.257 to 321.390 or any other law, or partially exempt from tax under ORS 307.250, 307.370 or 358.480 to 358.545 or any other law, the unit of property shall consist of all components of land and improvements in a single operating unit.

(3) In the case of timeshare properties, the unit of property shall consist of all real property components associated with all timeshare property within a timeshare plan as described in ORS 94.808.

(4) In the case of personal property that is not part of an operating unit consisting of both real and personal property, the unit of property shall consist of all items of personal property identified in a single property tax account.

(5) In the case of land upon which an improvement is located, and the land and the improvement are owned by different persons, if the land and improvements are a single operating unit, the unit of property shall consist of the entire improved parcel.