Washington Revised Code Title 26. Domestic Relations § 26.27.421. Duty to enforce

(1) A court of this state shall recognize and enforce a child custody determination of a court of another state if the latter court exercised jurisdiction in substantial conformity with this chapter or the determination was made under factual circumstances meeting the jurisdictional standards of this chapter and the determination has not been modified in accordance with this chapter.

(2) A court of this state may use any remedy available under other law of this state including writs of habeas corpus under chapter 7.36 RCW and enforcement proceedings under Title 26 RCW to enforce a child custody determination made by a court of another state. The remedies provided in this article are cumulative and do not affect the availability of other remedies to enforce a child custody determination.