Wash. Rev. Code § 13.34.161
In any case in which the court has ordered a parent or parents, guardian, or other person having custody of a child to pay support under RCW 13.34.160 and the order has not been complied with, the court may, upon such person or persons being duly summoned or voluntarily appearing, proceed to inquire into the amount due upon the order and enter judgment for that amount against the defaulting party or parties, and the judgment shall be docketed as are other judgments for the payment of money.
In such judgments, the county in which the order is entered shall be the judgment creditor, or the state may be the judgment creditor where the child is in the custody of a state agency. Judgments may be enforced by the prosecuting attorney of the county, or the attorney general where the state is the judgment creditor and any moneys recovered shall be paid into the registry of the juvenile court and shall be disbursed to such person, persons, agency, or governmental department as the court finds is entitled to it.
Such judgments shall remain valid and enforceable for a period of ten years after the date of entry.
RCW 13.34.161
Effective dates-Severability-1977 ex.s. c 291: See notes following RCW 13.04.005.