Backflow may be caused by either backpressure or backsiphonage. A loss of pressure in the public drinking water system may lead to backsiphonage through unprotected cross connections. Backpressure may be created when the water pressure of a facility’s internal water system is elevated above the supply pressure of the public drinking water system from water main breaks, unauthorized use of fire hydrants, etc., resulting in backflow through unprotected cross connections.
Backflow incidents potentially cause illness, chemical burns or even death. The installation and routine testing of backflow prevention valves help stop backflow threats from occurring.