I'm looking to install a new bathroom in my basement and a local plumber told me I can connect everything (sink,toilet,shower)to the main stack within 5-6 ft and I would not need to add a vent as the main waste stack would act as one. Is this true (also idk of it would help but 2 ft above where I would tie in the new bathroom is the drain line for the kitchen sink which is directly vented to roof without anything else above it) option 2 would be to cut into the sink drain earlier bring it underground enlarge to 3 in make all my connections and then tie into main stack. Do either of these work



Edited 1 times.

BOTH of those pipes are DRAINS, NOT vents, so they CANNOT be used as vents. And as far as what he told you about the distance from the main drain riser, it is FALSE, except for some special situations which I doubt apply to your installation. How long has he been a "plumber"?

No idea it's a friend of a friend situation-which is why I wanted to double check here. Why wouldn't option 2 be a valid wet vent?

You can't wet vent fixtures on a different floor levels. I assume the kitchen is on the 1st floor ?

All fixtures in the wet vent system need to be on the same floor level. Any drain piping coming from the floor above can't be used as a vent for fixtures on a lower level.

Because it is NOT on the same floor level as the sink. Which is also why an AAV is a bad idea for a lower level fixture.



Edited 1 times.

To properly run a vent would require ripping out the walls on first and second floor and a bit of ceiling (the walls don't line up anywhere on the side of the house) including jumping 2 or 3 joist bays. Would I be able to use an AAV to avoid the expense/time/mess. I know plumbers don't like using them but is that a pesonal preference/the way things were always done like pex vs copper or are there potential functional issues in a normal installation? Is it just a matter of the AAV failing and if I smell sewer gas open a window and replace the valve?



Edited 1 times.

Our code does allow the use of an AAV for a basement bath, just get it as high as you can, leave access to it, and be sure it can get plenty of air flow. If it's going to have to be in a wall, don't insulate around it and use a louvered grill over the opening in the sheetrock where it is.