What is the purpose of a dishwasher air gap?

The purpose of a dishwasher air gap is to prevent dirty water from siphoning back into the dishwasher. This component is critical in maintaining the hygiene and functionality of the dishwasher. The air gap acts as a physical barrier between the dishwasher’s drain and the home’s plumbing system, ensuring that wastewater cannot flow back into the dishwasher. If backflow were to occur, it could lead to contamination of the clean water being used in the dishwasher, posing health risks.

This device is typically installed at the sink and includes a small opening at the top, which allows air to enter, preventing any sort of siphoning effect. It’s a safeguard against cross-connection, which can be a significant concern in plumbing, especially in appliances that use both clean and dirty water. Having an air gap is a critical component of plumbing code requirements in many locations, reinforcing its importance in residential systems.

While enhancing efficiency, regulating water temperature, or filtering food particles are important aspects of a dishwasher's operation, they do not relate directly to the primary function of preventing backflow, which is the sole purpose of the air gap.