There shall be no physical connection between a potable, public, or private water supply system and such pools at a point below the maximum flow line of the pool, or to a recirculating or heating system of a pool, unless such physical connection is so installed and operated that no pool water can be discharged or siphoned into a potable water supply system. A vacuum valve shall be installed between the city water system or the entry of the pools operations. (Ord. 1329, §7, 1980).