My shower has tile up to the area just below the shower head. I recently noticed that the paint around the shower head is peeling badly, and there are water marks. The water marks appear to be older, and the area around the shower head is not wet. There is no spray from the shower head onto the wall when the water is turned on. I figured this means a leak inside the wall, but a plumber has told me he does not think so — he thinks it’s condensation. How do I tell without opening up the wall? I replaced the shower head some time ago, so it is possible the former shower head was leaking.