What is meant by an Air Gap?

An air gap refers specifically to the unobstructed vertical distance between the lowest point of a water supply outlet and the highest point of a downstream plumbing fixture or vessel. This distance is crucial in preventing backflow, which can occur when there is a drop in water pressure in the supply line. By maintaining an air gap, it ensures that any potential contaminants from a downstream fixture cannot flow back into the potable water supply.

This form of backflow prevention is considered one of the most reliable methods because it does not rely on mechanical parts or devices that could fail. The proper implementation of an air gap is essential for maintaining safe drinking water standards and compliance with health regulations. Understanding this concept is vital for water operators in managing water quality and protecting public health.