Garage Apartment Drain and Venting Plan Questions with Diagram

Users who are viewing this thread


New Member
Reaction score
Decatur, GA
I have built a two-story garage apartment, and I am ready for running DWV pipes. I have five fixtures, which I believe are called branch intervals, so pretty sure a vent stack is required. Most of my runs, except possibly the kitchen, which is in a wall 5 feet away, are under the minimum length runs to required for a separate vent, so I’m curious if vent runs A and B are necessary, or the bath sink and bathtub could be designated as individual wet vents as in 901.2.1. I am not sure if the horizontal distance only is calculated into the “maximum distance of fixture of trap from the vent” chart. If not, then, my kitchen sink would actually be within 8 feet of the main stack if vertical distance is not counted. I also wonder if my design is correct, especially the vent from the utility sink down below, and my pipe sizing. I would welcome any help or problems with this design. This is an especially difficult install because the framers did not only ignore my stud placement marks on the bottom plate of my 2x6 wall, but they also put a vertical 2x10 underneath this non-load bearing wall, so I have very little room for DWV, especially 3". Thank you very much for any help. Location = Decatur, Georgia.
Garage Apartment Drain Plan.jpg
Last edited:
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks