Venting question -- working on a remodel of a bath and only moving the lav. However, the existing DWV system is not ideal as one of the drain lines enters up into the floor right next to the wall, then takes a 90 into the wall and up. This was covered up by the original vanity, but that is being moved now.

The attached picture shows the current set-up (minus the yellow line -- that does not exist). I also attached a sketch of how the DWV looks, and how I am proposing with the changes. The vanity is moving about 20" away and turning 90 degrees along the back wall. There is a large 4" vent stack that will need to be moved back 20" as well.


I am asking if my proposed set-up works from a vent standpoint -- the question marks indicate I am not sure if 2" vent is necessary? Also, is there a specification for how close the vent line needs to tie into the toilet line? Ignore the 6' designation in the proposed sketch.

Thanks so much

Jason

45933

45935

45936

Bump de Bump... plus a small addition


The toilet drain and main vent is actually 3", no 4". I am guessing that in the current layout, the 3" main vent stack is serving as the vent for the toilet, since the other vent line is only 1.5" (2" is necessary for toilet, no?).

So, assuming that is the case --- since I am adding vents for both the lav and the bathtub, could I use 1.5" for the new yellow vent at the tub, and tie into the 3" main vent with a 2" drain pipe for the new lav? And would the toilet be OK so long as it was within 72" of where it ties into the 3" main stack?

Hi Jason

The new picture didn't load up. From what I can tell, you are headed in the right direction, but codes are very specific to your city/town so all I can really tell you is that your proposed setup looks correct...2" for tub drain and tub vent (which effectively "wet vents" the toilet).

Mark