California Code, Government Code - GOV § 960.8

Service of process in an action or proceeding against a public agency may be made in conformity with the information contained in the statement in the Registry of Public Agencies pertaining to that public agency which is on file at the time of that service. Service in this manner, if otherwise made in compliance with law, constitutes personal service upon the public agency.

As used in this section, “statement in the Registry of Public Agencies” means the statement or amended statement in the Registry of Public Agencies in the office of the Secretary of State or in the office of the county clerk of any county in which that statement or amended statement is on file.