Where does the vent go?

I can’t seem to find a clear answer on whether the vent for the toilet should be downstream of the toilet, or upstream.

I’ve enclosed a porch, and am installing a bathroom. My thinking was to run the vent behind the vanity, then the 2 in toward the shower, then from shower to my 3 inch toilet line. The vent behind the vanity would vent the vanity, shower, and toilet.

I could also put a vent in the wall between closet and bath (beside the door, before the shower).

I can also vent directly behind the toilet (that’s an interior wall), but would be after the other fixtures.

Any help would be appreciated, please don’t rag on my artist rendition of my addition. :smiley:


This might help.

Thanks, I saw this one, Dave. That’s running the line the opposite way, AWAY from my main drain to pick up vanity (shower is between them). I can’t make it work this way.

I think that’s it Jeff. Looks like my set up. Thanks for finding that drawing! I’ve been scratching my head over this for about a month, now it’s time git r done!


The others side is my office. It’s coming along nicely. It is, of course, adjacent to the kitchen! :wink:

very nice