Wash. Rev. Code § 10.77.132
If the defendant has been found not guilty by reason of insanity and a substantial danger, or presents a substantial likelihood of committing criminal acts jeopardizing public safety or security, so as to require treatment then the secretary shall immediately cause the defendant to be evaluated to ascertain if the defendant has a developmental disability. When appropriate, and subject to available funds, the defendant may be committed to a program specifically reserved for the treatment and training of persons with developmental disabilities. A person so committed shall receive habilitation services according to an individualized service plan specifically developed to treat the behavior which was the subject of the criminal proceedings. The treatment program shall be administered by developmental disabilities professionals and others trained specifically in the needs of persons with developmental disabilities. The treatment program shall provide physical security to a degree consistent with the finding that the defendant is dangerous and may incorporate varying conditions of security and alternative sites when the dangerousness of any particular defendant makes this necessary. The department may limit admissions to this specialized program in order to ensure that expenditures for services do not exceed amounts appropriated by the legislature and allocated by the department for such services. The department may establish admission priorities in the event that the number of eligible persons exceeds the limits set by the department.
RCW 10.77.132