I am installing a new toilet with PVC piping under the floor with limited space. From the flange, my 3" pipe extends vertically downward about two feet to a sweeping elbow which connects to the main drain about 10 feet away. I installed my 2" vent about 6" beneath the flange, extending rearward (horizontally) to the wall behind where the toilet will be and then up vertically through the wall and through the roof. My local inspector says this should be wet vented. I do not understand.