Toilet or drain leak. How do I find it?
I recently found a mushroom growing from under the baseboard/carpet of my family room. Needless to say, the carpet in that area was wet but because of the location and size of the wet area, it was not noticed sooner. I pulled the carpet back from the wall and have been trying to eliminate potential sources. I'm confident that the leak is coming from the toilet in the bathroom that is directly above that spot. Water only appears after flushing. I haven't used that toilet for 2 days and the area remains dry.
I removed the toilet and examined the wax ring and the flooring around the drain. There was no evidence of leaking around the base of the toilet. The wax ring was in good condition, the sub-flooring is clean and dry, and the flange appears to be solid.
I re-installed the toilet with a new wax ring; the toilet is stable (no rocking or movement). Again, I find no evidence of leaking from the toilet itself or around the wax ring/flange. Yet, when I flush, the water returns.
I suspect I will have to start cutting holes in the sheetrock. The drainage line is what I suspect. Since the incoming line is under constant pressure, if there were a leak in that line, wouldn't the leak be continuous?
I'd love any ideas or input, things I can do to further narrow it down or locate the source.
Thanks in advance!!!