toilet drain vertical minimum

Discussion in 'Toilet Forum discussions' started by glebbscout, Nov 23, 2006.

  1. glebbscout

    glebbscout New Member

    Nov 23, 2006
    What is the minimum vertical height between the bottom of where the bend starts in the horizontal drain pipe and the flange? Assume the drain pipe is 4" interior dimension and flange is 1/4". The center of the drain pipe is only about 18 inches from vent stack so not a lot of slope to it.

    _ (flange sitting on floor)
    min. vertical? l
    ________ (horizontal pipe line)

  2. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Nov 8, 2005
    Hansville, Washington
    It wouldn't be too hard to lay a closet bend against a flange in any of the big box stores to get a rough idea. I'd guess something like 6-7".
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  4. glebbscout

    glebbscout New Member

    Nov 23, 2006
    yes, but...

    I guess what I mean is: is it acceptable from a plumbing perspective to have such a short distance for the water etc. to flow from the toilet, into the drain before it hits the bend? If the flange measures 2 inches, roughly, top to bottom, plus the 4 inches until the bottom of the pipe, that's not much of a drop before it hits the bend. Does that matter?
  5. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    The minimum distance is as little as you can cut it and still get the flange to slide over with a good seal. Which usually means the riser has to be as long as the flange is deep.
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