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Definitions and Terms
Backflow in the water distribution system happens as a result of a reversal of the normal flow of water in the system. The two types of backflow are backsiphonage or backpressure. Backsiphonage is the reversal of flow of liquid caused by a partial vacuum in the potable water distribution system. This condition occurs when the supply pressure drops below atmospheric pressure. Backpressure is a condition in which the pressure in a non-potable system is greater than the pressure in a potable water system. Superior pressure will cause non-potable liquids to flow into the potable water distribution system through cross-connections.
- Hospitals, mortuaries, clinics, veterinary establishments, nursing homes, and medical buildings;
- Laboratories;
- Piers, docks and waterfront facilities;
- Sewage treatment plants, sewage pumping stations, or storm water pumping stations;
- Food and beverage processing plants;
- Chemical plants, dyeing plants and pharmaceutical plants;
- Metal plating industries;
- Petroleum or natural gas processing or storage plants;
- Radioactive materials processing plants or nuclear reactors;
- Car washes and laundries;
- Lawn sprinkler systems, and irrigation systems;
- Fire service systems;
- Slaughter houses and poultry processing plants;
- Farms where the water is used for other than household purposes;
- Commercial greenhouses and nurseries;
- Health clubs with swimming pools, therapeutic baths, hot tubs, or saunas;
- Paper and paper products plants and printing plants;
- Pesticide or exterminating companies and their vehicles with storage or mixing tanks;
- Schools or colleges with laboratory facilities;
- High-rise buildings (four or more stories);
- Multiuse commercial, office, or warehouse facilities; and
- Others specified by the purveyor or the division when reasonable cause can be shown for a potential backflow or cross connection hazard.