Cal. HSC § 119085

(a) Every public utility or utility district shall notify all electrical service customers of the electrical backfeed hazards of portable and permanent electric generators. (b) Any owner, renter, or lessee who possesses and operates an electric generator, when the generator is connected to a commercial, industrial, or residential structure’s electrical system that is connected to the service of a public utility or utility district, shall notify the utility of the location of the generator.