Drain question for adding second bathroom sink

Discussion in 'Remodel Forum & Blog' started by Carsonic, Oct 20, 2010.

  1. Carsonic

    Carsonic New Member

    Messages:
    3
    Location:
    Atlanta, GA
    I am adding a lav sink about 4 feet to the right of the existing one. I've built a little half wall to run the plumbing through so it goes behind my new cabinets. I need to know if I should put the tee in the vertical tailpipe section of the existing sink so I can plumb it similar to my 2 kitchen sinks only with a farther distance (my research so far indicates "probably not" :confused:) or if I should put it in the main.

    All I have seen are diagrams of drains halfway between the 2 sinks, so I'm concerned that there are issues with my asymmetrical setup that will cause me trouble. I am going from standard sinks to vessel sinks and raising the level of the countertop, if that makes a difference.

    Thanks for the help!

    (I live in GA, btw.)
    Last edited: Oct 20, 2010
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,313
    Location:
    New England
    Four feet is too long for one trap...the trap arm would collect crud and be open to the air and eventually generate some nasty smells. Depending on where the vent is, you might need some fancy footwork if it is essentially an island (you can't go up with the vent). You'll probably need a loop vent. A quick search will show you some possible ways to do this. A diagram of what you have and what you want might make it easier to comment.
  3. Carsonic

    Carsonic New Member

    Messages:
    3
    Location:
    Atlanta, GA
    Thanks Jim, here's a picture of what I'm doing.[​IMG]
  4. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    You're going to have to open the wall up.
  5. Carsonic

    Carsonic New Member

    Messages:
    3
    Location:
    Atlanta, GA
    Okay, why's that?
  6. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego

    Because you need to add another sanitary tee on the vertical stack. The distance between the two sinks would result in the "TRAP ARM" length exceeding code, and in general you cannot combine two traps into one trap arm either, so you need a new connection.

    I will say that based on what I have read on the forums over the years, the strictness that inspectors feel about this exact issue varies a lot. You might just want to add.

    If you "get away with it" that long arm will be prone to gunking up. Try to put a good slope down from the far sink.
Similar Threads: Drain question
Forum Title Date
Remodel Forum & Blog Shower drain re-venting question Jan 29, 2012
Remodel Forum & Blog Drain and Vent question in small bathroom Dec 13, 2011
Remodel Forum & Blog new toilet drain question Feb 17, 2008
Remodel Forum & Blog Double Lavatory drain/vent question Jan 26, 2006
Remodel Forum & Blog Toilet move using the same drain ..... Sep 19, 2014

Share This Page