International Residential Code (IRC) Plumbing Practice Test 2026 – All-in-One Resource to Master Your Exam!

A bidet must be equipped with an air-gap type or vacuum-breaker type supply fitting to ensure proper backflow prevention and protection of the potable water supply. This requirement is crucial because bidets are connected to the plumbing system and can involve both clean water supply and potential contaminants, especially if there is any change in water pressure or if there is a backflow situation.

The air-gap fitting functions by creating a physical separation between the potable water system and the waste system, preventing any possibility of contaminated water flowing back into the clean water supply. Similarly, a vacuum-breaker fitting also helps prevent back siphonage, ensuring that the water from the bidet does not contaminate the clean water supply if there is a drop in pressure in the supply lines.

In contrast, other types of fittings might not provide the same level of protection against contamination, which is why using an air-gap or vacuum breaker fitting is specifically mandated in plumbing codes for fixtures like bidets.