A runaway minor may maintain residency for a period not exceeding 45 days at a facility operated as part of a licensed program for runaway minors. The minor may maintain residency without the consent of the person or agency having custody of the minor, except that if the court has ordered the minor committed to the custody of the department, written consent of the department is required. The residency may be extended for an additional period of 45 days with the written consent of the person or agency having custody of the minor. A minor may not maintain residency beyond the 90th day following admission to a licensed program for runaway minors without the written consent of the person or agency having custody of the minor and the written consent of the department.