For the purpose of this subchapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
AIR GAP. The measured vertical distance from the lowest end of a potable water outlet to the flood rim or line of the fixture or receptacle into which it discharges. The minimum required AIR GAP shall be twice the effective opening of the potable water outlet.
APPROVED BACKFLOW ASSEMBLY. Any device that may be approved by the cabinet in lieu of proper air gap separation.
AUXILIARY WATER SUPPLY. Any water supply on or available to the premises other than the city's public water supply. These auxiliary waters may include water from any natural source such as a well, spring, river, stream or body of water or any water or other substance of unknown or questionable quality that may present a health or system hazard to the potable public water supply.
BACK PRESSURE. The flow of water or other liquids, mixtures or substances under pressure into the distribution pipes of a potable water supply system from any source other than the original water source.
BACK SIPHONAGE. The flow of water or other liquids, mixtures or substances into the distribution pipes of a potable water supply system from any source other than the original water source, caused by the reduction of pressure in the potable water supply system.
BACKFLOW. The reversal of the normal flow of water caused by either back pressure or back siphonage.
BACKFLOW PREVENTION ASSEMBLY. An assembly or means designed to prevent backflow. A listing of acceptable backflow prevention assemblies and degree of hazard is available in the State Plumbing Law, Regulations and Code.
CONTAMINATION. An impairment of the quality of the potable water supply by any waste product, fluid, substance, compound or other material to a degree which creates an actual or potential hazard to the public health through poisoning or through the spread of disease.
CROSS-CONNECTION. Any physical connection or arrangement of piping or fixtures between two otherwise separate piping systems one of which contains potable water and the other nonpotable water or substance of questionable quality, through which, or because of which, backflow may occur into the potable water system.
CROSS-CONNECTION CONTROLLED. A connection between a potable water system and a nonpotable water system with an approved backflow prevention assembly properly installed and maintained so that it will continuously afford the protection commensurate with the degree of hazard.
THERMAL EXPANSION TANK. A device installed on the cold water supply line near a water heater to compensate for the expansion of water within a water system when the water is heated.
(2000 Code, § 13-70)