Cal. HSC § 6500

If a district has a boundary which is contiguous to the boundary of a city and the district has a contract with that city under which the city is responsible for the operation and maintenance of all facilities of the district, the governing board of the district may, by a resolution adopted by a 4/5 vote of the board, declare the board dissolved and thereafter the governing body of the city shall be ex officio the governing board of the district.