Cal. Government Code § 18672

(a) Subpoenas and subpoenas duces tecum may be issued for attendance at a hearing and for production of documents at any reasonable time and place. However, a subpoena shall not be issued to compel attendance of any witness who does not reside within 100 miles of the place where the hearing or investigation is held unless it is shown to the satisfaction of a member of the board, the executive officer, or the person authorized to conduct the investigation or hearing, by affidavit stating the facts, that the witness is a material witness. That statewide subpoena shall be served at least five days prior to the date of hearing. (b) Subpoenas and subpoenas duces tecum shall be issued by the board or its authorized representative at the request of a party. (c) The process extends to all parts of the state and shall be served in accordance with Sections 1987 and 1988 of the Code of Civil Procedure and the service provisions of subdivisions (a) and (b) of Section 68097.1 of the Government Code. A subpoena or subpoena duces tecum may also be delivered by certified mail return receipt requested or by messenger. Service by messenger shall be effected when the witness acknowledges receipt of the subpoena to the sender, by telephone, by mail, or in person, and identifies himself or herself either by reference to date of birth and driver’s license number or Department of Motor Vehicles identification number, or the sender may verify receipt of the subpoena by obtaining other identifying information from the recipient. The sender shall make a written notation of the acknowledgment. A subpoena issued and acknowledged pursuant to this section has the same force and effect as a subpoena personally served. Failure to comply with a subpoena issued and acknowledged pursuant to this section may be punished as a contempt and the subpoena may so state. (d) No witness is obliged to attend unless the witness is a resident of the state at the time of service. (e) The custodian of documents that are the subject of a subpoena duces tecum may satisfy the subpoena by delivery of the documents or a copy of the documents, or by making the documents available for inspection or copying, together with an affidavit in compliance with Section 1561 of the Evidence Code.