Cal. Harb. and Nav. Code § 663.5
Within the territorial limits of a county, city, or district, a harbor policeman regularly employed and paid as such by the county, city, or district shall also enforce the provisions of this chapter and any rules or regulations adopted by the department pursuant to this chapter and the provisions of Chapter 2 (commencing with Section 9850) of Division 3.5 of the Vehicle Code.
In the exercise of his duties, a harbor policeman shall have the authority to stop any vessel subject to this chapter and to issue written notices to appear in court pursuant to Section 664. As used in Section 664, the term "officer" shall include a harbor policeman regularly employed and paid as such by a county, city, or district.
Every harbor policeman who is on duty for the purpose of enforcing the provisions of this chapter, and the rules and regulations adopted by the department pursuant to this chapter, shall wear a full distinctive uniform, and, if he uses a vessel, the vessel shall be painted a distinctive color and appropriately marked as specified by the department to identify it as a harbor police vessel.
Ca. Harb. and Nav. Code § 663.5