NEHA Certified Professional Food Manager Practice Exam 2025 - Free Food Safety Practice Questions and Study Guide

An air gap in plumbing systems is a critical feature designed to prevent backflow contamination, ensuring safe drinking water and maintaining hygiene in foodservice settings. The correct specification for an air gap is that it must be at least the same diameter as the water supply inlet. This requirement ensures that the air gap is effective in preventing any potential contamination from the drain or wastewater that could siphon back into the potable water supply.

When the air gap is equal to or greater than the diameter of the water supply inlet, it provides an effective barrier between the fresh water and potential contaminants. This is crucial in foodservice environments where the risk of cross-contamination can have serious implications for public health.

In contrast, while there might be various standards discussing minimum inches for air gaps in different contexts, these do not universally apply to all plumbing systems or pertain to all situations. For foodservice, ensuring that the air gap matches or exceeds the diameter of the inlet is a more accurate guideline to guarantee safe and functional plumbing.