What is the purpose of an air gap in plumbing?

The purpose of an air gap in plumbing is to prevent backflow and maintain water quality. An air gap is a physical separation between the end of a water supply outlet and the flood level of a fixture, such as a sink or a bathtub. This separation creates a barrier that prevents contaminants from entering the potable water supply.

When water is flowing, the pressure keeps it moving in the intended direction; however, if there is a drop in pressure or if some form of back siphonage occurs, the air gap ensures that no polluted water can be sucked back into the drinking water system. By maintaining this critical separation, the air gap plays a vital role in protecting public health and ensuring safe drinking water by adhering to plumbing codes and regulations regarding backflow prevention.