Half bath upstairs in a bungalow... one of those issues that doesn't seem right, but hasn't been a problem so I have ignored it. Now we're looking to sell in the spring and I'm trying to head off any potential issues.
The layout is sink on interior wall -> 4' to toilet -> 4' to vertical drain/vent stack on exterior wall. The sink is sized up to a 2" pipe after the trap, and somewhere in the floor sizes up to a 3" pipe before the toilet ties in. Essentially I've got 8' from sink to vent. I know this because it is all cased in a soffit on the first floor that I had open when I refinished a downstairs room.
I've been reading comments in other posts that venting is somewhat dependent on drain size and distance from the vent. Do I need to configure an AAV on the sink drain?
8 ft. to the stack on 3" DWV -that's a wet vent.
You've had no problems....
8 ft. isn't that far - probably would be OK.
We would probably, re-vent the sink just to be on the safe side.
Maybe wait to see if "TheEplumber", or others stop by, to get another