I occupy a condo for 3 years bought new, however I have some water infiltrations between the wall of the shower and the bedroom and this from the beginning. I am sure there is a water leak in the tubing but the developer never wanted to break the wall to find out or come these infiltrations. I do not know what to do with each one developer puts a painting but they still have nothing resolved. Someone could advise me ?

Pay to have it done yourself may be the only answer.

There can be a lot of causes: leaking in bathroom on the floor above, inferior grouting in the bathroom, a leak in piping.

I can imagine that the developer/juristic office isn't really interested in investigating/solving the problem; they just don't know where to search. 

 

Following giddyup's advise may be the only right thing. 

I had both leaking in the wall and bad grouting...after fixing the leaky wall I was dismayed to still have a slight damp patch on the outside of the bathroom wall,only after moving the emergency waterbucket I found
Some grouting that had been eaten away by toilet cleaning solution containing hydrochloric acid (don't use that stuff on your bathroom floor it cleans very well but eats the grout) after repairing that the damp patch went away.

The first thing I would check is that the tap isn't leaking where it screws into the wall. I had a dampness problem on the wall in the bedroom that separated the bathroom. I envisaged having to break all the tiles out to get to the problem, turned out I only needed to put some more white plumbers tape on the thread where the tap attached. It may be that simple.