I'd like to tap into an existing 2" tub drain with a 2" drain for a new vanity.
Can you tap into an existing tub drain with a 2" drain for a new vanity?
The tub is approx. 5' from the main stack and vent. The connection for the sink would be around the 3' mark on the tub drain leaving about 2' until it reaches the main. The lavatory will be approx. 6'6" from the main stack & vent.

You do realize that unless you come off the existing vent with a sanitary tee with a two inch branch to pick up the lavatory that you will need to run a separate vent for the lavatory don't you? Regards, tom

Hey Tom,

Thanks for the advice. What I don't understand is as of right now the tub and the existing lavatory along with the toilet all drain into 1 stack and that stack is in the wall where it continues up through the roof acting as the vent. Is it still necessary for a separate vent for the new lavatory? The new location for the lav is across from the existing which is only at most 6' from the main stack and the vent.
The tub drain is very close to where I want to place the new lavatory. It would be ideal if I can just tap into the tub drain line.

Let me know. Thanks for your time. I really appreciate it!