Oregon Revised Statutes Revenue and Taxation § 311.216

(1) Whenever the assessor discovers or receives credible information, or if the assessor has reason to believe that any real or personal property, including property subject to assessment by the Department of Revenue, or any buildings, structures, improvements or timber on land previously assessed without the same, has from any cause been omitted, in whole or in part, from assessment and taxation on the current assessment and tax rolls or on any such rolls for any year or years not exceeding five years prior to the last certified roll, the assessor shall give notice as provided in ORS 311.219.

(2) Property or the excess cost of property, after adjustment to reflect real market value, shall be presumed to be omitted property subject to additional assessment as provided in ORS 311.216 to 311.232 whenever the assessor discovers or receives credible information:

(3) If the tax collector discovers or receives credible information or if the tax collector has reason to believe that any property subject to taxation has been omitted from the tax roll, the tax collector shall immediately bring this to the attention of the assessor by written notice.