Cal. Civ. Code § 704.21

704.21 Manner of giving notice.
(1) Notice by landlord. Notice by the landlord or a person in the landlord’s behalf must be given under this chapter by one of the following methods:
(a) By giving a copy of the notice personally to the tenant or by leaving a copy at the tenant’s usual place of abode in the presence of some competent member of the tenant’s family at least 14 years of age, who is informed of the contents of the notice;
(b) By leaving a copy with any competent person apparently in charge of the rented premises or occupying the premises or a part thereof, and by mailing a copy by regular or other mail to the tenant’s last-known address;
(c) If notice cannot be given under par. (a) or (b) with reasonable diligence, by affixing a copy of the notice in a conspicuous place on the rented premises where it can be conveniently read and by mailing a copy by regular or other mail to the tenant’s last-known address;
(d) By mailing a copy of the notice by registered or certified mail to the tenant at the tenant’s last-known address;
(e) By serving the tenant as prescribed in s. 801.11 for the service of a summons.
(2) Notice by tenant. Notice by the tenant or a person in the tenant’s behalf must be given under this chapter by one of the following methods:
(a) By giving a copy of the notice personally to the landlord or to any person who has been receiving rent or managing the property as the landlord’s agent, or by leaving a copy at the landlord’s usual place of abode in the presence of some competent member of the landlord’s family at least 14 years of age, who is informed of the contents of the notice;
(b) By giving a copy of the notice personally to a competent person apparently in charge of the landlord’s regular place of business or the place where the rent is payable;
(c) By mailing a copy by registered or certified mail to the landlord at the landlord’s last-known address or to the person who has been receiving rent or managing the property as the landlord’s agent at that person’s last-known address;
(d) By serving the landlord as prescribed in s. 801.11 for the service of a summons.
(3) Corporation or partnership. If notice is to be given to a corporation notice may be given by any method provided in sub. (1) or (2) except that notice under sub. (1) (a) or (2) (a) may be given only to an officer, director, registered agent or managing agent, or left with an employee in the office of such officer or agent during regular business hours. If notice is to be given to a partnership, notice may be given by any method in sub. (1) or (2) except that notice under sub. (1) (a) or (2) (a) may be given only to a general partner or managing agent of the partnership, or left with an employee in the office of such partner or agent during regular business hours, or left at the usual place of abode of a general partner in the presence of some competent member of the general partner’s family at least 14 years of age, who is informed of the contents of the notice.
(4) Notice to one of several parties. If there are 2 or more landlords or 2 or more cotenants of the same premises, notice given to one is deemed to be given to the others also.
(5) Effect of actual receipt of notice. If notice is not properly given by one of the methods specified in this section, but is actually received by the other party, the notice is deemed to be properly given; but the burden is upon the party alleging actual receipt to prove the fact by clear and convincing evidence.