Cal. Government Code § 7927.105

(a) As used in this section, the term “patron use records” includes both of the following: (1) Any written or electronic record that is used to identify a library patron and is provided by the patron to become eligible to borrow or use books and other materials. This includes, but is not limited to, a patron’s name, address, telephone number, or email address. (2) Any written record or electronic transaction that identifies a patron’s borrowing information or use of library information resources. This includes, but is not limited to, database search records, borrowing records, class records, and any other personally identifiable uses of library resources, information requests, or inquiries. (b) This section does not apply to either of the following: (1) Statistical reports of patron use. (2) Records of fines collected by a library. (c) All patron use records of a library that is in whole or in part supported by public funds shall remain confidential. A public agency, or a private actor that maintains or stores patron use records on behalf of a public agency, shall not disclose those records to any person, local agency, or state agency, except as follows: (1) By a person acting within the scope of the person’s duties within the administration of the library. (2) By a person authorized in writing to inspect the records. The authorization shall be from the individual to whom the records pertain. (3) By order of the appropriate superior court.