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 backflow prevention is an air gap.

See also

• Pressure vacuum breaker
• Double check valve
• Chemigation valve
• Reduced Pressure Principle BFP
• Atmospheric vacuum breaker