Hydrostatic loop

A Hydrostatic Loop, though not often used in Plumbing practice,is an arrangement of pipes formed into a vertical "loop" to prevent Backflow of water within the plumbing potable water system. Since a Siphon has a maximum height that it can work( about 33 feet)a Hydrostatic Loop is built higher than 33 feet. There are several ways to prevent siphonage and an undesirable backflow of the water in a plumbing system. One form of a Backflow Preventer is an "Air Gap".