How to Detect Water Leakage in a House If you are looking to detect a leak in the plumbing system, it is best to check for them in copper pipes. The leak is detectable as a white circle due to the salt collection within the water that crystallizes near the crack or hole on the leaking pipe. Although it is not the most efficient method, you can look for leaks in your plumbing system by looking at the meter. After closing all of your inlets and taps, see if there is still movement on the water meter. If it is, you know there is a leak somewhere.