When the upstairs bathroom showers are turned on (either one) it sounds like drops of water “falling” to the lst floor inside the wall near the kitchen sink. I do not see any evidence of a leak. What do you think the problem is??
You might have a cracked pipe are a fitting leaking, are if it is pvc it might be the water making a noise in the pipe, watch where you here it for any signs.You might be able to feel wall and see if it is hot or cold.
Just a thought – try pouring a quantity of water directly down the shower waste pipe and then listen for the noise you are hearing – if it is there then it may just be as said above the water dribbling down inside a plastic waste pipe within the wall – or it could even be that the shower waste pipe is connected into the same waste pipe that the kitchen sink runs into and the sound is just an amplification of water running through a plastic waste pipe. You do not say if you have a concrete floor or what so I suggest that if it is wooden with a crawl space under it have someone run the shower while you look round the floor plate for any wet or water dripping down – this would obviously indicate a leak is within the wall cavity somewhere. Hope this helps some.
Selgas Services Ltd Craftsman Gasfitters, Plumbers, Electrical Service Technicians