A building's potable water supply line is suspected of having a leak underground in a non-accessible area. After isolating a section and seeing a pressure drop, you need to pinpoint the leak. What is the next logical step before excavation?

Question: A building's potable water supply line is suspected of having a leak underground in a non-accessible area. After isolating a section and seeing a pressure drop, you need to pinpoint the leak. What is the next logical step before excavation?

Answer options:

• Introduce dye into the water supply ✅ Use a ground microphone or acoustic leak detector
• Perform a visual inspection with a borescope
• Increase water pressure to force water to the surface

Correct answer: Use a ground microphone or acoustic leak detector

Explanation: After confirming a pressure drop in an isolated section, using a ground microphone or acoustic leak detector is the logical next step. These tools can 'listen' for the sound of escaping water through the ground, helping to pinpoint the leak's exact location before excavation. Introducing dye or increasing pressure are not appropriate or safe methods for underground potable water leaks.