More of a general question than anything. Does anyone know why toilet manufacturers don't make the lip on the toilet flange long enough to extend down into the floor drain flange, thus eliminating the leak problem? I know that the wax ring still would be needed for sewer gases, but, wouldn't an extended lip prevent water leaks without the need of a wax ring? They do make wax rings with a rubber flange for the same purpose, so, why not permanently part of the toilet?

Even if the lip were taller you still need a seal because china and steel don't seal. A rubber or neopreme collar molded into the toilet would be a good innovation but the toilet as it comes from the kiln is all china and adding a collar would be one more step that they see no need for since wax rings have been available for decades and work well.

Hey Ken,
Does anyone know why toilet manufacturers don't make the lip on the toilet flange long enough to extend down into the floor drain flange, thus eliminating the leak problem, why not permanently part of the toilet?
But they do already. Turn any toilet bowl over and you'll see a horn about 3 or 3 1/2 inches that extends down past the flange. This directs the flow into the closet bend but does not make a air tight seal. The wax seal does that. Hope this clears ip up for you. Regards, tom