What is the required distance between the end of the water supply pipe and the sink?

The required distance between the end of the water supply pipe and the sink is based on plumbing codes aimed at preventing contamination and ensuring proper drainage and flow.

The correct choice indicates that the distance should be two times the diameter of the supply pipe. This guideline helps to ensure that any potential back-siphonage or contaminants present in or around the sink do not enter the drinkable water supply. The prescribed distance provides a safety buffer, allowing air to act as a break between the water supply and any possible contaminants that could be present, such as soap, food particles, or other pollutants.

By establishing a physical separation based on the diameter of the pipe, plumbing practices aim to maintain the health and safety of the water supply system, reducing the risk of cross-contamination. Keeping this in mind, other measurements such as 1-1/2 times, 3 times, or 4 times the diameter are not routinely recognized in standard plumbing codes for this specific application.