drip... drip... drip...

We have a pretty new toilet--it's a Toto one-piece. When you sit on it, you can hear a dripping, about 1 drip per second. This dripping begins when you sit down and continues for a while, but not forever: it doesn't drip all night.

If, while it's dripping, you open the tank, you can push on the flap and stress other inside-the-tank components without causing any change in the dripping.

If you turn off the water to the toilet, the tank doesn't empty. While it's dripping, there's no visible turbulence in the tank or the bowl.

My theory is that sitting down compresses the seal or otherwise disturbs the toilet and the water is somehow dripping down the drain (water from the bowl flowing over the P-trap?)

But I can't figure out why it drips for so long (at least a few minutes) and so regularly. Is it possible that the seal compresses and it takes a while to return to its shape?

Thanks for your ideas or opinions.

All toilets get the bowl filled to the brim, like filling a glass to overflowing. It's just that that brim isn't the top of the bowl, but the height of the internal passageways. If the toilet or floor moves at all when you sit, you could be tipping the bowl enough for some water to drain out. This is also true when you are adding stuff to the bowl - the overflow will drain. Some toilets allow you to hear that more readily than others, and Toto's with the Unifit adapter (which is plastic rather than porcelain) don't dampen the sound as much as a more traditional toilet where the trap is made in the toilet verses being in the adapter. If the toilet doesn't rock when you sit on it, which should be fixed regardless of the brand or type, what you are hearing is normal.

drip

Unless you are making a tight seal when you sit on the seat, you are not doing anything to force water out of the bowl.

drippage

Yeah, it's definitely not water being forced out of the bowl by air pressure: it's much more regular than that would be, and it continues for a while after you stand up. We're also definitely not sealing the opening.

I currently like the explanation that it's water overflowing the bowl, either because the toilet tips a little bit (it definitely doesn't rock, but it's possible that the floor or the toilet/floor junction compresses a little bit) or because something has been added to the bowl. Maybe the design of this toilet just leads to a gradual draining of this overflow via audible dripping.

I plan to do the following experiments: pour a little bit of water into the bowl and see if that starts the dripping. Also, see if there's any visible shift to the toilet when sitting.

Thanks for your comments. Any more thoughts or experiment suggestions would be appreciated.

Toto toilets with the Uni-Fit is what gets the most complaints, becuase it's platic and echos.
Toto has an adapter that will fit on the end of the overflow tube, in esseance what it does is reduces the water level in the bowl and when you sit and add volume to the water it's not enough to overflow into the uni-fit.
This is a tiny part and Toto should be able to send one out to you.
I had a few, but doubt if any other wholesaler would.
You can call them at 1-888-295-8134 and press 4 for technical.

If you do that, you'll probably reduce the water spot. While maybe disconcerting, the drip isn't a problem, assuming it is what I think it is. You get used to it, and it causes no damage.