How do i fix a cold water leak between floors?

Question

How do i fix a cold water leak between floors?

Answer 1

If the leak is in an inaccessible location, then the only way to fix it is the same way the plumber would do it. Tear out enough floor or ceiling to make the repair, then get a carpenter, or other contractor to fix the ceiling.  

Answer 2

Turn off the water, replace worn section. You would cut the pipe above and below where you think the leak is and rejoin the pipe with a new section, some teflon tape, soder and torch.