When your toilet tank is not secure you could develop a leak. This guide is about toilet tank wobbles.
We installed a new toilet and something doesn't seem right. My husband said he tightened the bolts that hold the tank onto the bowl, but it wobbles as if they are extremely loose. I was very worried about this, so he put a small piece of 2 X 2 between the tank and the wall. Now there is no wobble, the tank is level, flushes right and doesn't leak, but I'm still worried. Anyone have any ideas?
You might want to check the toliet flange under the toliet meaning where the pipe and the toliet meet, you might need a new wax ring or your floor from the leaking might be rotting out your floor, I found this out the hard way myself. I would suggest taking the toliet out and check what you have going on there, mine rotted out the whole floor around the hole, not a good situation.