California Code, Business and Professions Code - BPC § 22971.5

Any notice required by this division shall be served personally or by mail. If by mail, the notice shall be placed in a sealed envelope, with postage paid, addressed to the licensee at the address as it appears in the records of the board. The giving of notice shall be deemed complete at the time of deposit of the notice in the United States Post Office, or a mailbox, subpost office, substation, or mail chute, or other facility regularly maintained or provided by the United States Postal Service, without extension of time for any reason. In lieu of mailing, a notice may be served personally by delivering to the person to be served and service shall be deemed complete at the time of delivery. Personal service to a corporation may be made by delivery of a notice to any person designated in the Code of Civil Procedure to be served for the corporation with summons and complaints in a civil action.