A 2nd story living quarters is perched atop of a ground floor office.
There is high certainty based on history and observations that there is a slab leak: assume this is the case for this question. It is desirable to find the water feed into the upstairs (entry point for a bypass).
There is a very similar second office / apartment configuration that has a copper pipe, that comes out of the slab, travels behind an office wall vertically and bridges and provides water to the 2nd floor:
A visual inspection was performed to find the water feed for said apartment: a copper pipe candidate is thought to be the the water-feed.
The goal is to confirm that it is the water feed without cutting the pipe.
What tests can be performed on said candidate copper pipe to confirm that it is the water feed? Tests that are simple, easy, can be performed without elaborate tools (especially avoiding cutting) are appreciated. Thank you