Cal. Gov. Code § 41601

For the suppression of riot, public tumult, disturbance of the peace, or resistance against the laws or public authorities in the lawful exercise of their functions, and for the execution of all orders of the local health officer issued for the purpose of preventing the spread of any contagious, infectious, or communicable disease, the chief of police has the powers conferred upon sheriffs by general law and in all respects is entitled to the same protection.