Upstairs we have back to back bathrooms. Below one we have a third bathroom.

I used one of the upstairs toilets and later found it running and water on the floor. It wasn't coming out of the bowl when I got there, but I think it had. The side of the bowl was damp.

I checked downstairs and there was a lot of water on the floor but none on the walls or ceiling. The side of that bowl was damp as well, but not currently overflowing. Three feet away from that toilet is a shower with NO dampness.

Six feet away from the upstairs toilet is a shower that a tile guy just started remodeling yesterday. The tile guy is exceptionally neat and had laid a folded section of blanket over the open shower drain so nothing would fall in. NO dampness here. Since the shower walls are open, I can see the shower's vent pipe (~2" copper, 50 yr old house). In the attic I can see where that joins a 4 or 5" copper vent pipe from near the toilets before penetrating the roof near the peak. I haven't gone up to check the roof.

Both toilets flush and clear now.

So what happened? A clog in the main stack after downstairs toilet? That cleared itself? And didn't cause any dampness in either shower? I don't know how the lower level waste pipes join together. Maybe the clog was before that shower. Why no dampness in the upstairs shower?

Could the covered shower drain have affected venting somehow? Only if my vents are blocked?

Also, my wife tells me that the upper bathroom toilet overflowed maybe 2 weeks ago. She used the plunger on it. No water downstairs.


Thanks for any insights!



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