Cal. Health and Safety Code § 1580.9

Any person may request an inspection of any adult day health center in accordance with the provisions of this article by transmitting to the state department notice of an alleged violation of applicable requirements prescribed by statute or regulation. Any such notice shall be in writing, specifying to a reasonable extent the details of the alleged violation, and shall be signed by the complainant. The substance of the complaint shall be provided to the licensee no earlier than at the time of the inspection. Unless the complainant specifically requests otherwise, neither the substance of the complaint provided the licensee nor any copy of the complaint or any record published, released, or otherwise made available to the licensee or the public shall disclose the name of any person mentioned in the complaint, unless the complainant is a duly authorized officer, employee, or agent of the state department conducting the investigation or inspection pursuant to this article.