California Codes, Code of Civil Procedure - CCP, Part 3 — Of Special Proceedings of a Civil Nature, Title 3 — Of Summary Proceedings, Chapter 4 — Summary Proceedings for Obtaining Possession of Real Property in Certain Cases, Section 1162

(a) Except as provided in subdivision (b), the notices required by Sections 1161 and 1161a may be served by any of the following methods:

(1) By delivering a copy to the tenant personally.

(2) If he or she is absent from his or her place of residence, and from his or her usual place of business, by leaving a copy with some person of suitable age and discretion at either place, and sending a copy through the mail addressed to the tenant at his or her place of residence.

(3) If such place of residence and business cannot be ascertained, or a person of suitable age or discretion there can not be found, then by affixing a copy in a conspicuous place on the property, and also delivering a copy to a person there residing, if such person can be found; and also sending a copy through the mail addressed to the tenant at the place where the property is situated. Service upon a subtenant may be made in the same manner.

(b) The notices required by Section 1161 may be served upon a commercial tenant by any of the following methods:

(1) By delivering a copy to the tenant personally.

(2) If he or she is absent from the commercial rental property, by leaving a copy with some person of suitable age and discretion at the property, and sending a copy through the mail addressed to the tenant at the address where the property is situated.

(3) If, at the time of attempted service, a person of suitable age or discretion is not found at the rental property through the exercise of reasonable diligence, then by affixing a copy in a conspicuous place on the property, and also sending a copy through the mail addressed to the tenant at the address where the property is situated. Service upon a subtenant may be made in the same manner.

(c) For purposes of subdivision (b), “commercial tenant” means a person or entity that hires any real property in this state that is not a dwelling unit, as defined in subdivision (c) of Section 1940 of the Civil Code, or a mobilehome, as defined in Section 798.3 of the Civil Code.