Hello,

I live in a condo building. The unit below me is complaining that my toilet is causing their ceiling to mold. I know that there is no water leaking from underneath the toilet when I flush the toilet, as nothing shows up on my floor.

However, I do not know what is happening below my toilet and which is in proximity to the area of my neighbors ceiling where they are finding mold.

The bolts on my toilet were a little loose so I tightened them. I was thinking I could replace the wax gasket as a precaution. However, I want to make sure that makes sense and is the likely culprit. Perhaps the loose bolts moved the ceil enough to cause leakage below me, though I am guessing that if there was a leak in the seal, I would see water flooding from underneath the toilet onto my floor. Otherwise since no leak on my floor, I am wondering if the more likely culprit it the p-trap or other plumbing attached somewhere from my toilet flange downwards.

No obvious leaking below, just the mold stain on the drywall ceiling below.

What is the most likely cause ?

Thanks
Randy

You won't see water on your floor if it's leaking.

There is no p-trap in the plumbing pipes for the toilet. The toilet contains an integral p-trap.

Seal is the likely culpret.