California Code, Harbors and Navigation Code - HNC § 630

The operator of every privately or publicly owned marina or small craft harbor, or facilities in connection therewith, furnishing electrical power to slips or berths for use aboard any vessel, may provide facilities for submetering to measure the electrical power actually used by or aboard each vessel and may base charges therefor upon that use including the actual cost of inspection, testing, and registration of submeters that may be charged by any authority having jurisdiction thereof.