Undermount Sink and Garbage Disposal Potential Issue

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by ms222, Dec 8, 2013.

  1. ms222

    ms222 New Member

    Messages:
    12
    Location:
    Florida
    I do not know much if anything about plumbing so bare with me please.

    So I am remodeling my kitchen and I'm on my last step. All of my cabinets are in. Moving the drain pipe is not really an option as the piping is in stucco/cinderblock and has an elbow that runs about 35" or more horizontally, so it would be a disaster.

    Here's the situation. I have a single basin undermount kitchen sink. The distance from the sink drain to the centerline of my in-wall vent drain is exactly 7". I currently own an insinkerator compact disposal, where according to manufacturer specifications, the distance between the sink drain and the centerline of the disposal discharge arm is 6". Instead of using a 90 degree arm from the disposal I would want to use a horizontal straight pipe to have the disposal discharge arm 1" higher than the in wall drain vent.

    My dishwasher is directly to the right of my sink cabinet.

    Below is my empty setup (sorry for picture quality).

    I am having a plumber come on Wednesday to install everything, can I get away with the disposal being 1" higher than the main drain, as technically water wouldn't have to travel upwards.

    If not, does anyone know of a disposal that has a smaller distance than 6" to the discharge arm? I looked all over and did not see any. plumbing.jpg
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,770
    Location:
    New England
    As long as the outlet of the disposer is above the inlet to the wall, a plumber should be able to make it all work. It's when the outlet is lower than the inlet in the wall where it is a problem.
  3. ms222

    ms222 New Member

    Messages:
    12
    Location:
    Florida
    The outlet based on my measurements will be 1/2" to 1" higher than the inlet to the wall. Hope this will suffice. How would my setup work if I used a horizontal straight discharge pipe in terms of it being able to hook up to the ptrap and not clog up?
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,161
    Location:
    Cave Creek, Arizona
    The problem will be getting the trap and disposer elbow to fit together within that 1" dimension, since the trap inlet is higher than the outlet pipe, and the disposer, or any other 90, will need some space for its radius. For compatibility reasons most disposers have the same dimension, other than batch feed models which are even lower. Even if you use a "horzontal pipe" it still has to turn downward at the trap.
    Last edited: Dec 9, 2013
  5. ms222

    ms222 New Member

    Messages:
    12
    Location:
    Florida
    Is there anyway that a professional licensed plumber will be able to make this work? I just redid the kitchen and really dont want to have no disposal. At the same time, the drain pipe is so far away that moving it will tear up a lot of my brand new cabinets.
  6. Terry

    Terry Administrator Staff Member

    Messages:
    14,680
    Location:
    Bothell, Washington
    [​IMG]

    You may want to pick up a J Bend Low Inlet for your p-trap.

    [​IMG]
  7. ms222

    ms222 New Member

    Messages:
    12
    Location:
    Florida
    Hi Terry, thanks for your advice. Do you have a picture by any chance of a setup similar to mine that uses that pipe so I can visualize how it works?
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,161
    Location:
    Cave Creek, Arizona
    The problem with low inlet traps is that when the nuts are at the same "elevation", the inlet is almost as shallow as using a conventional trap "backwards". If you notice the one in the picture on the package has the inlet nut higher and it shows a "socket" for the tailpiece to slide into giving a more rigid and secure connection.
  9. ms222

    ms222 New Member

    Messages:
    12
    Location:
    Florida
    HJ, I am not sure whether you are saying it will be just a challenge, or if it will not be possible. I understand this is less than ideal, but in all practicality, moving the drain pipe is out of the picture, and if it can be done, even if not as secure, I'm willing to take the chance.


    Anyone viewing this thread, please let me know if given the picture of my setup, and the 1" differential, if there is anyway to make this work? I am having a plumber come for $375 flat rate tomorrow, and don't want to end up having to settle on no disposal when he may try to tell me he can't do it because he is not up for a challenge that day. I just want to know if its theoretically possible to make this work, and maybe a picture or a diagram showing how to present to him. Thank you!
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,161
    Location:
    Cave Creek, Arizona
    Depending on how it is done, it could be less than ideal, but will work. "$375.00"? I would like to install them all day long for that price. Just don't come back tomorrow, like a previous poster" and ask if you got "taken" because he was only there 30 minutes.
  11. MACPLUMB 777

    MACPLUMB 777 TROJAN WORLDWIDE SALES RP

    Messages:
    679
    Location:
    Houston, Texas, United States
    I think the poster was talking hooking up ever thing under the sink
    new faucet, supplies as whale as the g/d drain
Similar Threads: Undermount Sink
Forum Title Date
Plumbing Forum, Professional & DIY Advice, Tips & Toto undermount sink issue - ring around outside of drain Jun 25, 2014
Plumbing Forum, Professional & DIY Advice, Tips & Are cast iron undermount sink clips model-specific or generic? Sep 15, 2011
Plumbing Forum, Professional & DIY Advice, Tips & Buying a double bowl undermount sink Jul 31, 2011
Plumbing Forum, Professional & DIY Advice, Tips & kitchen sink: trying to find off center drain undermount sink Sep 29, 2010
Plumbing Forum, Professional & DIY Advice, Tips & replacing undermount bathroom sink. Need advice Sep 6, 2010

Share This Page