Master Plumber Practice Exam 2025 – Complete Prep Guide

Using soapy water to detect leaks in gas piping is a widely accepted and effective method because it allows for easy identification of escaping gas. When soapy water is applied to the exterior of the piping, any escaping gas will disrupt the surface tension of the soap solution, creating visible bubbles. This visual indication makes it straightforward for a plumber or technician to locate the precise spot of the leak.

This method is also safe for use with gas lines, as it does not introduce any substances that could react adversely or cause corrosion, which can be a concern with other methods. Additionally, soapy water is non-flammable, reducing any risk associated with the presence of gas.

In the context of the other options, using fire or acid could pose significant risks and are not appropriate for leak detection. Applying potable water to the inside of pipe tubing would not effectively reveal leaks in the piping's structure. Using a noncorrosive leak detection fluid may also be effective, but it is typically less accessible and practical than the soapy water method, which is inexpensive and easy to use for immediate identification of leaks.