To further what Bob said, the floor drain in the restroom would never get any water down it and the water in the trap would eventually evaporate out leaving a open pipe with no seal between the sewer and the occupied space. In your own thought you even question how you would get a sanitizer into the pipe knowing that it would have to overcome the pressure in the pipe. When you flush the toilet the water pressure pushes water out that pipe allowing the inlet side of the trap for the floor drain to be charged thru a pipe that is in the wall and continues under the floor to where it terminates just above the trap seal. If it was sanitzer they would have to somehow synchronize the flush valve with a pressure pump that would buildup more pressure then the water supply, this in turn would allow the sanitizer to go back thru the water supply system while the valve was open flushing, since the sanitizer pressure would be greater then main pressure. No such connection would ever be permitted.
» This message has been edited by turdchaser on 16 April 2004