Cal. HNC § 268

(a) Counties or cities may adopt restrictions concerning the navigation and operation of vessels and water skis, aquaplanes, or similar devices subject to the provisions of subdivision (a) of Section 660, and may grant permits to bona fide yacht clubs, water ski clubs, or civic organizations to conduct vessel or water ski races or other marine events over courses established, marked, and patrolled by authority of the United States Coast Guard, city harbormaster, or other officer having authority over the waters on which such race or other marine event is proposed to be conducted and on such days and between such hours as may be approved thereby. These provisions shall not apply to marine events authorized by United States Coast Guard permit.

(b) The provisions of this section shall apply to all waters which are in fact navigable regardless of whether they are declared navigable by this code.