Public Utilities Code § 1406
CHAPTER 8. Determination of Just Compensation for Acquisition of Utility Properties
Service of the order to show cause shall be made in accordance with the provisions of the Code of Civil Procedure or by depositing a copy of the order to show cause certified under the seal of the commission with a copy of the petition attached thereto, in the United States mail, enclosed in a sealed envelope, registered, with postage prepaid, addressed to each of the owners or claimants, at the address specified in the petition.