How far can I come of the p trap of my tub before venting? It is a 2" line and will be hitting a 332 wye about 8 ft away

Hey Gabe, Ready for a little good news? You may not have to run a separate vent for the tub. If you do then code calls for five feet from the pipe that connects the trap to the vent opening. However, if you have a existing bathroom group you are already vented through the lavatory vent. Tell me more about this three inch line. Is it a horizontal line from thr toilet or is it a vertical vent stack? If it's a drain line from the toilet make sure your 3 X 3X 2 tee is cut in below,(downstream) from where the lavatory branches in to it. Code states that you can not discharge a major fixture, (toilet) past a unvented minor one, (your tub). However cutting in downstream from the lavatory will wet vent your tub and keep you legal. It's difficult to explain vents, revents and wet vents so if I haven't made myself clear click on back with a precise explanation of your drainage lay out and I'll try again. Good luck, Tom

THANKS FOR THE REPLY, right now it's set up so the toilet sweeps down to a 3 in waste line, there is a 3" wye in the vertical stack below the toilet that goes up and catches a 332 sanitery t that picks up the lavatory off of the 2" line through the wall and the 3 inch continues vertically to the roof (exterior stack).. the 2" tub line would connect to the 3" waste line/vent just below the lavatory.. let me know if I'm being clear enough, thanks

Go for it! You're vented. Good luck, Tom

Thanks a lot for the help..