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Thread: add laundry sink to washer drain?

  1. #1

    Default add laundry sink to washer drain?

    Hi. I'm adding a laundry sink next to my washer and was thinking I could just cut off the top of the standpipe where my washer now drains, then plumb in a tee to come out of the wall in order to put in my sink drain and ptrap. I would then just have the washer drain into the sink. The only problem (is it a problem?) it that there is a ptrap in the wall a the bottom of the washer stand pipe and the sink would now have two ptraps. issue or nonissue?

    Thanks

  2. #2
    Master Plumber Redwood's Avatar
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    A double trapped sink woud be a problem that could create a flood.

  3. #3
    Master Plumber Redwood's Avatar
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    You actually need to configure the drain pipe inside the wall something like this to do what you want to do. This would ensure proper drainage and venting.


  4. #4
    Moderator & Master Plumber hj's Avatar
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    Default drain

    Cut the trap off and install an elbow facing out of the wall. Then connect the sink's P trap to that, if you are not going to use the pipe in the wall for the washer drain. If you do plan to keep the current connection and add a sink, (by connecting it to the washer's standpipe), then you will not really have the classic two trap situation, nor will you even need a P trap on the sink.

  5. #5

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    Quote Originally Posted by hj View Post
    Cut the trap off and install an elbow facing out of the wall. Then connect the sink's P trap to that, if you are not going to use the pipe in the wall for the washer drain. If you do plan to keep the current connection and add a sink, (by connecting it to the washer's standpipe), then you will not really have the classic two trap situation, nor will you even need a P trap on the sink.
    OK. So it sounds like I can use a properly vented and trapped washer standpipe (correct term?) to drain both the washer and a laundry sink and they will both share the ptrap at the bottom of the standpipe? Perhaps some water will come up into the sink when washer is draining? This sounds like the same as a dishwasher draining into the kitchen sink's ptrap.

  6. #6
    Master Plumber Redwood's Avatar
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    No!
    You can have both plumbed in per the picture I posted above.

    or,

    You can eliminate the washing machine standpipe and elbow out to a sink drain & P-Trap and then drain the washing machine into the sink.

    You cannot have the washer and the sink share a trap!

  7. #7
    Moderator & Master Plumber hj's Avatar
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    Default sink

    You CAN connect the sink to the standpipe, but it would not pass an inspection. You CAN use the washer p trap connection, after you cut off the P trap, for the washer and then drain the washer into the sink. This is an approved method.

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