Utility Sink Installation

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by ttsmith, Jan 30, 2013.

  1. ttsmith

    ttsmith New Member

    Messages:
    7
    Location:
    Anchorage
    I was hoping to complete an installation of a utility sink into an adjacent washing machine drain. I spent a good amount of time studying another thread on here, and it has helped a lot, but I'm not exactly sure how to adapt the recommendation to my current setup. The example that was given in the other thread is this:

    washer_rough_b.jpg

    And the drain/vent situation I have looks like this:
    DSC_4874-2.jpg

    So, my questions:
    - Does the washing machine drain have to be below the sink (as it is in the example), or can the sink be below?
    - If the sink is lower, than obviously it would need the vent "bypass" rather than the washing machine. Could I run this "bypass" to the neighboring vent stack (on the left in the picture) rather than the one the washer uses?

    Thanks very much for the help. I can't seem to find anyone who has a definite idea on the proper way to do this. I'm in Anchorage, which I believe is UPC if that is significant.

    Thanks again,

    Travis
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,006
    Location:
    New England
    Is the pipe on the left a vent or a drain? Once a drain, always a drain. You may need to open up some of the wall to determine what you need to do. Which side of the whole thing do you want to install the sink on?
  3. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,246
    Location:
    Land of Cheese
    We would be allowed to plumb the sink over the washer as long as the vent is indeed a vent. Problem in your case might be that the sink is too low. Sometimes it is easier to raise the sink rather than reconfigure the plumbing.
  4. Terry

    Terry Administrator Staff Member

    Messages:
    15,004
    Location:
    Bothell, Washington
    As long as the washer and the sink are vented before they combine in a waste stack you would be okay. Then the two vents can tie together.
    Sometimes it's easier to cut out what little you have there and start from scratch. A blank sheet is so much easier.
    For one thing, the washer standpipe you have is longer than it needs to be.
    Or if you have room for it, you can still put the sink in above the tee for the washer. You will need to increase to 2" above the santee though.
  5. ttsmith

    ttsmith New Member

    Messages:
    7
    Location:
    Anchorage
    Thanks everyone for the help. This is already clearing things up. To follow-up: the sink will be to the left of the washer. I do plan to remove most of the existing washer drain/vent and re-do it to incorporate the addition. My main hope is that I can do everything without removing drywall or certainly not cement.

    Can the horizontal run from the sanitary tee to the street-trap adapter for the sink be 1-1/2" instead of 2"? The vent above the sanitary-tee is 1-1/2", and the washer drain is 2".

    Thanks again,

    Travis
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,631
    Location:
    Cave Creek, Arizona
    Lower the washing machine connection and install the sink connection above it and ALL your venting questions are taken care of. The branch to the sink can be 1 1/2".
  7. ttsmith

    ttsmith New Member

    Messages:
    7
    Location:
    Anchorage
    But I don't have much room to lower the washing machine connection--only about 1" or so below is where the coupling is to go to cast iron.

    So if I connect the sink above the washing machine I don't need any vent changes? Do you mean I can just add another san-tee on top of the washing machines, and it would lead to the sink? Wouldn't I then just have the same situation as that example I posted originally, but without the vent bypass?

    Travis
  8. Terry

    Terry Administrator Staff Member

    Messages:
    15,004
    Location:
    Bothell, Washington
    In Arizona, you can put the laundry tray above the washer if the santee is a 2x2x1.5
    Most other places would require that the washer has it's own vent.
    If it's being inspected, you can ask your inspector what he will pass.

    I like to show pictures that pass everywhere. It's less confusing that way.
  9. Hammerlane

    Hammerlane New Member

    Messages:
    252
    Location:
    Ohio
    Doesnt this distance need to be a minimum of two inside pipe diameters???

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