Draining sink & washer to same standpipe?

Discussion in 'General Plumbing Help' started by Jason W., Dec 30, 2019.

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  1. Dec 30, 2019 #1

    Jason W.

    Jason W.

    Jason W.

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    All, thanks in advance for the help.

    I’d like to add a utility sink near my washer. Currently there is one standpipe, shown in the picture and it does not vent through the roof, also no trap. Is it a big deal to drain both a sink and washer into the pipe?
    I planned to expand left [pic] for the washer and add draining for the sink to the right. Rough sketch over actual pic attached.

    any issues with this Approach, also should I add AAV to the top of the pipe since it doesn’t vent outside?
     

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  2. Dec 31, 2019 #2

    Jeff Handy

    Jeff Handy

    Jeff Handy

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    Is that standpipe plumbed into an old floor drain?

    Or maybe a rough-in for a toilet?

    If either of these are true, then there is probably a trap already under the floor.

    You can verify a trap under the slab by shining a light down there, if you see standing water it has a trap.
    Or the drain is clogged, haha.

    Or poke a stick down, and if three or four inches of the end are wet, it has a trap.
     
  3. Dec 31, 2019 #3

    Jason W.

    Jason W.

    Jason W.

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    It is nearby/inline with a floor drain and the light showed some water, stick had a few inches wet, think you’re right. See any issues with me cutting in the T for the Sink drain?
     
  4. Dec 31, 2019 #4

    Jeff Handy

    Jeff Handy

    Jeff Handy

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    The pros on here can advise, but I think you can run both down there.

    Or plan B, just connect your new slop sink to the standpipe, cap the standpipe with an AAV, and run the washing machine drain over the side of the slop sink.
    Capping the standpipe might help with odors.
    Laundry has lots of fibers that will rot in the drain and create stink.

    But I am not a pro, so wait for better advice as it trickles in!
     
  5. Dec 31, 2019 #5

    frodo

    frodo

    frodo

    Just call me Macgyver Professional Supporting Member

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    just my thoughts
    you say there is a floor drain inline with this pipe. that would lead me to believe that pipe is the vent for the floor drain

    if you stacked the tees the way your drawing shows. i believe the washer would suck the laundry sink trap dry
    but if you use a wye...like this

    ford fan.png
     
  6. Jan 16, 2020 #6

    Diehard

    Diehard

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    NSPC Figure of Standpipe.jpg 2018 IPC IPC 2018 laundry tray to standpipe.jpg
     

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