Hello,

I own a 1st floor condo with one bathroom. There is one identical condo directly above me. I do not know if the pipes are shared.

My problem is that when the toilet is flushed, the bowl will fill correctly but within a few hours of inactive use the bowl will empty on its own to about a tea cup of water.

Can someone tell me what the problem is and how to fix it? I removed the toilet and put in a new wax seal, this solved the problem for a week or so but is now back and worse than before. I have searched for leaks but none to be found.

As you flush and the float ball drops, turning on the ballcock so it fills the tank it also diverts water through a small 1/8" tube from the top of the ballcock into the top of the white overflow pipe. This flow adds water to the water in the bowl to bring the level up. Make sure the 1/8" tube is clear and is pumping water into the overflow pipe and not in the tank. That's the first thing I would check. There could also be a factory defect in the bowl. Sometimes in casting the bowl there is a small bubble in the china. Instead of junking the bowl the manufacture will put a porcelain patch over the hole and send it on through. On occasion the patch will fail allowing the water to seep out of the bowl. If that's the case you would have a full bowl after you flushed and the bowl filled but some hours later you would notice a drop in the bowl level. The only other thing might be if you dropped something in the bowl and cracked it. If you're worried about where the water's going, in both cases it drains back down into the sewer and not under the bowl on the floor. Hope this helps . Tom

Hey Tom, I liked your answer. Do you think he may be getting a siphon from the unit above him due to a partially blocked vent?