California Code, Code of Civil Procedure - CCP § 514.020

(a) At the time of levy, the levying officer shall deliver to the person in possession of the property a copy of the writ of possession, a copy of the plaintiff's undertaking, if any, and a copy of the order for issuance of the writ.

(b) If no one is in possession of the property at the time of levy, the levying officer shall subsequently serve the writ and attached undertaking on the defendant. If the defendant has appeared in the action, service shall be accomplished in the manner provided by Chapter 5 (commencing with Section 1010) of Title 14. If the defendant has not appeared in the action, service shall be accomplished in the manner provided for the service of summons and complaint by Article 3 (commencing with Section 415.10) of Chapter 4 of Title 5.