This next picture is going to show a pipe coming out of the toilet and will go into the tank in the bay to catch any additional liquid. We already have a holding tank inside the bottom of the toilet to burn off any excess liquid that may accumulate. Since this toilet was made for a family of five in a part time setting, we should really have no problem with any liquid over and above what may drain into the holding tank, but, the brochure says to do it, so we did it.