Wash. Rev. Code § 71.06.260
At any time any person is committed as a sexual psychopath the court shall, after reasonable notice of the time, place and purpose of the hearing has been given to persons subject to liability under this section, inquire into and determine the financial ability of said person, or his or her parents if he or she is a minor, or other relatives to pay the cost of care, meals and lodging during his or her period of hospitalization. Such cost shall be determined by the department of social and health services. Findings of fact shall be made relative to the ability to pay such cost and a judgment entered against the person or persons found to be financially responsible and directing the payment of said cost or such part thereof as the court may direct. The person committed, or his or her parents or relatives, may apply for modification of said judgment, or the order last entered by the court, if a proper showing of equitable grounds is made therefor.
RCW 71.06.260