Declares that inpatient treatment may not exceed one hundred twenty days in RCW 13.40.165.

Provides that with the exception of youth committed to the department of social and health services, juvenile rehabilitation administration, when an adjudicated offender is ordered to be confined pursuant to a disposition or modification order, the court may grant credit for time served or to be served in a voluntary substance abuse or mental health inpatient treatment facility, even though such facility is not a "detention facility" as defined by RCW 13.40.020.