Will this toilet venting work?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by koa, Jul 12, 2014.

  1. koa

    koa Member

    Messages:
    76
    Location:
    Hawaii
    I have a toilet rough-in that was done by a plumber when I built the house 35 years ago. I never hooked up a toilet due to building dept not allowing half bath due to a slopping ceiling which never made much sense to me.

    I've recently decided to install an Ultramax. I notice there wasn't much slope to the drain line and was thinking I should probably put a little more slope in it. The copper line is in the way to just pull the drain line down a bit. I can move the copper or just have the drain go under it. That's not a problem either way. My concern is the way the plumber vented the drain. In the pic you can see the vent and drain are horizontal for about about 4' before the vent goes up to the roof and the drain goes down. The third pipe on far left is for venting a bath behind the wall on left. They connect in the floor above about 3' from the floor before one goes up through the roof. Will this work? If it's not to code, what is the reasoning why this shouldn't be done. The toilet flange is attached directly to elbow on the upper side of floor.

    Thanks.

    [​IMG]
    Last edited: Jul 12, 2014
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,156
    Location:
    Bothell, Washington
    You're not allowed to flat vent like that. A santee horizontal like that is a no-no, as is the vent 90 below the flood level.
    Since this is a toilet, which is meant to siphon, would have vented back at the wall, or even installed a wye below the 90 on the vetical where it bends down, with a wye fitting and 45 over to the vent he used.

    Since that is open, you could just install it and see how it works. As longs as the vent stays clear, it works. More than likely, since the Ultramax whooshes out of there, there won't be much to clog things. If you ever have an issue, well, it's all open.
  3. koa

    koa Member

    Messages:
    76
    Location:
    Hawaii
    I wonder why the plumber vented it the way he did? It seems like he was trying to get the venting as close to the toilet as possible. Venting back at the wall like you suggest would have been easier than what he did.

    If I'm going to change the slope I might as well change the venting since I'm cutting into it and it's all really clean. Just want to double check if this is correct along with how the existing toilet vent attaches to the roof vent with a regular T fitting.

    [​IMG]
    Terry likes this.
  4. Terry

    Terry Administrator Staff Member

    Messages:
    15,156
    Location:
    Bothell, Washington
    That looks nice. :)
  5. JustAHomeOwner

    JustAHomeOwner Member

    Messages:
    41
    Location:
    NY
    on a properly pitched horizontal run is there a max distance from the toilet flange to the vent line?
  6. Terry

    Terry Administrator Staff Member

    Messages:
    15,156
    Location:
    Bothell, Washington
    Six feet for 3" or 4"
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