California Code, Harbors and Navigation Code - HNC § 660

(a) Any ordinance, law, regulation, or rule relating to vessels, which is adopted pursuant to provisions of law other than this chapter by any entity other than the department, including, but not limited to, any county, city, port authority, district, or any state agency other than the department, shall, notwithstanding any other provision of law, pertain only to time-of-day restrictions, speed zones, special-use areas, and sanitation and pollution control, and the measure shall not conflict with this chapter or the regulations adopted by the department.  Except as provided in subdivision (c), any measure relating to boats or vessels adopted by any governmental entity other than the department shall be submitted to the department prior to adoption and at least 30 days prior to the effective date thereof.

(b) The department may make special rules and regulations governing the use of boats or vessels on any body of water within the territorial limits of two or more counties, cities, or other political subdivisions if no special rules or regulations exist or if the department determines that the local laws regulating the use of boats or vessels on that body of water are not uniform and that uniformity is practicable and necessary.