How to install dishwasher drain to double sink?

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by TCiura, Sep 18, 2007.

  1. TCiura

    TCiura New Member

    Messages:
    1
    I am remodeling my kitchen and I am adding a dishwasher. Previously there was none. I know my local ACE hardware sell's a pvc branch with tail to attach dishwasher drain. My question is with a dual sink setup how do I attach the branch tailpiece and the horizontal pvc piece that connects both sinks? Does anyone have a diagram or website where I can see a diagram of the setup? Everything I find only has examples for a single sink setup.

    Thanks for your help
  2. End outlet
    with
    dishwasher branch connection

    Search on these terms.


    Also:
    Center outlet
    CONTINUOUS WASTE
    dishwasher Wye
    dishwasher Tee


    -david
  3. Livin4Real

    Livin4Real New Member

    Messages:
    192
    Location:
    Indianapolis, IN
    If there is enough pipe after the trap (between sink trap and floor of cabinet) in the vertical section would be a good place to put a wye for the dishwasher.
    That's how I plan on running the one I'm about to install in our remodel.
  4. wyoplumb

    wyoplumb Master Plumber

    Messages:
    1
    Location:
    wyoming
    do not install after the trap. It is possible to get sewer gas through your line and into your dishwasher which in turn you will get the gas in your kitchen area. You need to put the branch wye in before the trap. you may need to lower your waste outlets coming off of your sink strainer baskets.
  5. Livin4Real

    Livin4Real New Member

    Messages:
    192
    Location:
    Indianapolis, IN
    I was assuming there would be a trap for the dishwasher as well. The one-piece p-traps.
    Last edited: Sep 19, 2007
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,515
    Location:
    Cave Creek, Arizona
    livin4real

    Connecting it directly to the drain system, with or without a trap, is usually illegal because contamination in the DW could occur very easily under the right conditions.
  7. you will see diagrams aplenty, Tciura, so you will know that your trap is the last thing in the series.

    what have you found so far? What material is your "tubular" made of. Tubular is one more good word to use in key word searches.

    Tubular is the pipe stuff that repairpeople, handymen and handywomen are allowed to change out, without being licensed as plumbers.


    david
  8. Livin4Real

    Livin4Real New Member

    Messages:
    192
    Location:
    Indianapolis, IN
    OK, going to try and redeem myself now, lol.

    [​IMG]
  9. Terry

    Terry Administrator Staff Member

    Messages:
    14,911
    Location:
    Bothell, Washington
    [​IMG]
    This picture above is legal plumbing where they use the UPC plumbing code. Uniform Plumbing Code.

    S-traps that go through the bottom of the cabinet like the drawings in the post above would not be legal in UPC country.
  10. GrumpyPlumber

    GrumpyPlumber Licensed Grump

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    1,404
    Location:
    Licensed Grump
    I don't think they're legal anywhere.
  11. Livin4Real

    Livin4Real New Member

    Messages:
    192
    Location:
    Indianapolis, IN
    I give up, lol.That's bad when the manufacturer's drawings aren't right.

    Now, after searching the archives here, the loop system was mentioned several times as being a good alternative but also not being code since alot of areas require the airgaps, some folks complaining about airgaps and water getting under them into the countertops. What's your opinions on the loop system? I also thought the new DW's have one-way check valves on the drain to keep bad stuff from getting in? I'm glad this thread came up cause I've learned alot.
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,924
    Location:
    New England
    First, check with the local code people...you may not have a choice. An air gap is a guaranteed way to install it safely. A high loop is a gamble...admittedly, a long-shot, but still a gamble on overall safety.
  13. sparky828

    sparky828 New Member

    Messages:
    2
    I'm going to tack onto this thread

    Hello all. I apologize in advance for my lack of knowledge of the correct terms. I hope my descriptions will paint an accurate picture.

    I'm struggling with this issue as well. At present, I have two sinks, no disposal and a dishwasher that was draining on the wrong side of the trap. Each sink has a horizontal pipe that runs to a central piece that then sends the water vertically down to the j-bend. I tried to put the piece with the branch between the joining piece that drain from the sinks and the j-bend, but even after sawing down the bottoms of both the fitting and the branch piece, they are a maddening 1/2" too long for the j-bend to meet the . Now I see why my father-in-law put it where he did when he installed the dishwasher :)

    Is it possible/legal to put the piece with the dishwasher branch in a horizontal position in place of one of the horizontal pieces before the join?

    Here's the old configuration for reference:
    [​IMG]

    Thanks!
  14. krow

    krow Plumber

    Messages:
    906
    Location:
    Ontario, Canada
    Yes it is legal, but you will have to use a Wye instead of a T
  15. sparky828

    sparky828 New Member

    Messages:
    2
    Thanks much for your response, and this where I further confirm my ignorance. I'm guessing the difference between a Wye and a T hinges on the angle at which the stem comes off of the tube. If that's what it is, then I think it's a Wye I have (the perspective in the picture above is misleading).

    This is the piece I'm thinking of using (already partly cut in my previous attempt to fit it vertical):

    [​IMG]

    Wye? Wye not?
  16. krow

    krow Plumber

    Messages:
    906
    Location:
    Ontario, Canada
    That will work if you have enough space in the horizontal (probably the right side , judging by your original pic)
  17. Gudtime

    Gudtime New Member

    Messages:
    1
    Location:
    Lethbridge, AB Canada
    Terry..My Double Sink like above (minus the Disposer..) uses Copper Pipe. I got a Dishwasher Instal Kit with it, however it is only for a Single sink. Looking for the Best/Cheapest route.. I have seen Co.'s like Keeney showing the Dual Sink Drains w/ the Dishwasher Drain..(END OUTLET CONTINUOUS WASTES - WITH BAFFLE TEE - SLIP JOINT) Should I just Replace the existing Copper Pipes with ABS..or just go with a Wye and Adaptor in between the sinks ? Also, the supplied Hot Water Line is 60"..so I am about 40" too short..(Drain Hose is plenty long enough) This is a 'New Instal'..not a replacement..can I splice in another 40" with a 3/8 nipple..? Also..is this going to be too far of a Run for proper draining ? Didn't really want to remove cabinets to get closer !
    Last edited: Oct 26, 2012
  18. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,334
    Location:
    Yakima WA
    I'm not sure I understand if you have a disposal or not when you say,"minus the disposal". If you have a disposal, the dishwasher drains into it. There is a knock out plug in the side of the disposal where it goes. Be sure you remove the plug and not leave it inside. If you do not have a disposal, then you use the tee as shown in a couple of post back. Depending on where you live, an air gap may be required. The hose from the DW connects to one side of the air gap and a hose to the sink drain connects to the other side before the P trap. Somd places allow a high loop instead of an air gap, and in that event, the hose from the DW must be looped and attached under the counter so that the loop is higher than the DW. Make sure the hose will not kink where it is attached to the counter top. Then the hose goes to the drain as described above. An air gap is always legal, high loops are OK in just some places. As far as the supply line is concerned, you can splice onto the existing line or replace it with a single line that is long enough. I use a line that has the braided steel cover and attach it to the water supply with a 1/4 turn valve. Of course you are free to use whatever method you prefer.
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