Originally Posted by freshstart
We are doing some plumbing work tonight so I am hoping someone can answer my question quickly. Is a 3" vent needed for each toilet or can you get by with a 2"? The way it is laid out right now, we have a toilet that flows into a jet tub drain and then into a shower drain. What would be the proper way to vent that sequence of fixtures?
A house requires one 3" main vent. On new construction we usually make this vent the kitchen sink vent6. The rest can be 2". You have a major fixture discharging past two unvented minor ones. Both the shower and the tub will have to be vented individually, the vents will have to be installed Just downstream of each trap. However, they may be connected together and revented back into a dry vent. Good luck, Tom

A house requires one 3" main vent. On new construction we usually make this vent the kitchen sink vent6. The rest can be 2". You have a major fixture discharging past two unvented minor ones. Both the shower and the tub will have to be vented individually, the vents will have to be installed Just downstream of each trap. however, they may be connected together and revented back into a dry vent. Good luck, Tom
You can use a 2" vent by international code. A 3" vent was needed in the old code. A toilet should be on a 3" line. A jet tub should be on a 2" line.. The vent should be after any trap. On a 2" line you you can run up to 8' to a vent. You can use a dry vent. Like a tee on its back or a combo(wye with a 45) and run up any wall to the outside. I hope this helps.. Stephen