Wash. Rev. Code § 26.09.280
Every action or proceeding to change, modify, or enforce any final order, judgment, or decree entered in any dissolution or legal separation or declaration concerning the validity of a marriage or domestic partnership, whether under this chapter or prior law, regarding the parenting plan or child support for the minor children of the marriage or the domestic partnership may be brought in the county where the minor children are then residing, or in the court in which the final order, judgment, or decree was entered, or in the county where the parent or other person who has the care, custody, or control of the children is then residing.
RCW 26.09.280
Part headings not law-Severability-2008 c 6: See RCW 26.60.900 and 26.60.901.
Severability-Effective date-Captions not law-1991 c 367: See notes following RCW 26.09.015.