Cal. Welf. and Inst. Code § 380
Any person adjudged to be a dependent child of the juvenile court may be permitted by order of the court to reside in a county other than the county of his or her legal residence, and the court shall retain jurisdiction over that person.
Whenever a dependent child of the juvenile court is permitted to reside in a county other than the county of his or her legal residence, he or she may be placed under the supervision of the social worker of the county of actual residence, with the consent of the social worker. The dependent child shall comply with the instructions of the social worker and upon failure to do so shall be returned to the county of his or her legal residence for further hearing and order of the court.
Ca. Welf. and Inst. Code § 380