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Thread: Convert basement Toilet to Drain?

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  1. #1

    Default Convert basement Toilet to Drain?

    I was directed to this forum to ask my question... hopefully you guys can help me...

    I just baught a house and there is a very nice room in the basement with a fireplace and everything! I plan on building a bar with a draft system... but rather than have a drip tray (they cost upwards of $75) I got a sink. Same price, better utility. The problem is: Where to drain it

    Directly on the other side of the wall from the sink is a toilet. It's mounted directly to the concrete floor and is about 2' from my furnace. Almost totally useless. I don't think the toilet is vented.

    My question is:
    A. Can I just pull the toilet, attach some sort of fitting to the drain and drain my sink into via a plain old P-trap?

    B. My fiancee seems convinced the toilet might be usefull at some point. Is there a fitting that would raise the toilet and allow me to run PVC under it to drain the sink into? I would obviously have to create a subfloor to raise the toilet. If this is possible would it cause problems with the sink when you flushed? Sewer gas in my bar would suck.

    Any other tips or ideas would be appretiated as well.


  2. #2


    IMHO, you're better off 'pulling' the toilet now, draining yr sink into the drain (w proper ptrap and vent) and then relocating the toilet to a preferable place flush (no pun intended) with the ground.

    If you do as yr wife says, you'll have a badly located toilet at a crappy (no pun intended) height. It'll look like a hack job.
    (important note: I'm not a pro)

  3. #3


    Do I have to vent the drain if it's going into a floor mounted drain like this? The toilets not vented...

    Also... This is a basement... moving the toilet would involve a Jackhammer. I would rather just get rid of it.

  4. #4
    Homeowner geniescience's Avatar
    Join Date
    Nov 2005
    humid summers hot, humid winters cold


    every toilet has a P trap inside it. Thus, a toilet drain has no P trap since you can't have two P traps in series. Your drain in your floor is made for a toilet. It has no P trap. It cannot serve as a floor drain alone, since it has no P trap.

    You have two options if you remove the toilet. Either you attach plumbing to it so that a sink drains into it, with a sink P trap between the sink and the current drain. Or, you break open the concrete and add a P trap to the drain so that it now is a standalone floor drain.

    More complicated options are available too...

    First things first. Do you have a floor plan, or idea of where you want things to be? I find it hard to believe that someone is not sure whether or not he wants to keep a toilet or not. Either you have the space or not. Either your planned space layout makes sense or not.

    To pull a toilet does not require breaking concrete. You unscrew bolts and slide (rotate) it off. It's easy and fast.


    p.s. After you figure out what you want to do... then venting is the next big question. Where are your closest vents?
    p.p.s. no a floor drain doesn't need a vent. A sink may not require anything more than a little AAV vent, so don't let venting constraints decide for you what you want to do with your space.
    Last edited by geniescience; 03-20-2007 at 01:59 PM.

  5. #5


    Ok, screw the toilet. People can go upstairs.

    What is this AAV? Does it stand for "open Air vent"? Can you link me a picture?
    Also, how do I tie into the toilet drain? I saw an adapter at ******* (like home depot) that looked like it would convert from the toilet fitting to 3" PVC. If I use something like this, how do I seal it? The wax toilet fitting or somethign eles?

    I'm still trying to figure out my layout... it's going to be highly dependent on how I configure this drain.

    Here's a rough scetch of my basement... directly behind the toilet are the cold-air return vents. I was planning on moving the door from the room with the fireplace and moving that wall back a few feet... that would be the bar. There is another drain right in fron of the toilet... but I can't run anything to it without blocking off a door. My furnace is HUGE and from the 1960s... but I dont plan on replacing it for about another year.
    Last edited by Charliemopps; 03-20-2007 at 03:25 PM.

  6. #6
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    New England


    AAV=air admittance valve; Studor is one brand, and they are often called that sort of like Kleenex for a tissue or Xerox for a copy. I sort of thing if you are going to have a bar...a toilet would be nice, but it needs a sink!
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014


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