3" Toilet Drain

Discussion in 'Toilet Forum discussions' started by KShirriff, Nov 8, 2012.

  1. KShirriff

    KShirriff New Member

    Messages:
    14
    Location:
    Tuscaloosa, Al.
    I have a toilet drain on the 2nd floor directly above a 2x6 wall on the 1st floor. Can I run the 3" drain from the toilet flange straight down to the basement without any elbows at the top and tie into the horizontal drain line? I have a 2" vent tied into the 3" pipe about 18" below the toilet flange and vented up throught the roof. Someone said that they think this design might suck the water out of the toilet trap. Is this true?
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,139
    Location:
    New England
    That's a really long drop but it won't suck the toilet trap dry with a vent. Not sure if that would meet codes...just don't know.
  3. Terry

    Terry Administrator Staff Member

    Messages:
    15,124
    Location:
    Bothell, Washington
    It doesn't matter whether it drops straight down or has a few bends.
    Hopefully the bowl "does" siphon when you flush. The fill valve refills the bowl after a flush anyway. I would have no problem with a toilet drain run straight down. Wait..........I've done hundreds that way.

    [​IMG]
    Last edited: Nov 8, 2012
  4. KShirriff

    KShirriff New Member

    Messages:
    14
    Location:
    Tuscaloosa, Al.
    should I put an elbow in it and offset it over and then down?
  5. KShirriff

    KShirriff New Member

    Messages:
    14
    Location:
    Tuscaloosa, Al.
    Here is a pic plumbing.jpg
  6. KShirriff

    KShirriff New Member

    Messages:
    14
    Location:
    Tuscaloosa, Al.
    going to reroute the vent at a 45 degree
  7. KShirriff

    KShirriff New Member

    Messages:
    14
    Location:
    Tuscaloosa, Al.
    Thanks Terry
  8. Terry

    Terry Administrator Staff Member

    Messages:
    15,124
    Location:
    Bothell, Washington
    Running the vent for the toilet on a vertical or a 45 is a good idea.
  9. wjcandee

    wjcandee Wise One

    Messages:
    1,894
    Location:
    New York, NY
    I was going to say that you could replace that combo with a Y for the vent, which is effectively what they are saying above.
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