Came across this problem recently: When waste is introduced into the toilet, a dripping sound starts (from the toilet, not the user ;-)). Waited for the tank to start filling but it never fills leading me to believe that the water level in the tank is not affected. It seems that as the level of water in the bowl is raised by the waste there is water flowing (dripping sound) from the bowl end of things. Any thoughts on what that is all about? Toilet is Toto Ultramax II, one piece design.