Oregon Revised Statutes Human Services; Juvenile Code; Corrections § 416.422

(1) Past support may not be ordered for any period of time prior to the later of:

(2) If the administrator has issued a notice and finding of financial responsibility under ORS 416.415 that includes a statement of past support but the administrator or an administrative law judge has not issued an order, and a court proceeding that involves the same obligor and child support for the same child is pending or is commenced after the notice is issued, the administrator may certify all matters under the notice to the court for consolidation in the court proceeding. After the matter is certified to the court, the court may, in the same manner as the administrator, order a parent to pay an amount of past support.

(3) If the administrator does not certify the matter to the court under subsection (2) of this section and the court's judgment or order does not address past support, the administrator or an administrative law judge may thereafter issue an order directing a parent to pay an amount of past support.