Sometimes you will get your piping leaked which you will wonder where is the exact location. This is because the pipe that leaked inside the concrete might not show up in the exact location as the water sip where ever there is or are weak linage inside the concrete wall. For example, in this case, the sign where the water leak is not at the broken pipe was but show up some about one meter and somewhere else.
It was lucky that the guy who actually did the job has experience in a situation like this. He pointed out that the leak must be inside the wall and not on the ground. If we took it wrongly, it might cause damage to the portion in the location by digging the floor. We might keep dig and dig at the wrong spot !.
We knew how it can happen. This can happen due to some 10 years minor vibration. Whenever we turn on the Tap, the water rushes up to feed the open taps and hence it causes some vibration that made it grind on the concrete. When this happens for some 10 years, it will weaken the pipe and punctured the pipe.