Well, I`ll suffer the slings and arrows that may come from this question. I am a fairly capable homeowner and fix most things myself. I am remodeling the only bathroom in the house. I am moving the toilet from right next to the 4" cast iron drain/vent pipe which is using a very short 90 from the floor of the bathroom to the cast pipe to a location on the other side of the room. The distance is now approx six foot from the cast drain/vent pipe I need to know if I HAVE to use a vent pipe or not. I have many other questions, but this will help me decide an overall plan of action