Cal. Welf. and Inst. Code § 4426
The department may inquire into the manner in which a person with an intellectual disability who is subject to commitment, not confined in a state hospital, is cared for and maintained. If, in its judgment, the person is not properly and suitably cared for, the department may apply to a judge of the superior court for an order to commit him or her to a state hospital under the provisions of this code. This order shall not be made unless the judge finds, and certifies in the order, that the person is not properly or suitably cared for by his or her relatives, legal guardian, or conservator, or that it is dangerous to the public to allow him or her to be cared for and maintained by the relatives, legal guardian, or conservator.
Ca. Welf. and Inst. Code § 4426