Add laundry sink to washer drain?

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djbabyk

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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?

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Redwood

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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.

washer_rough_b.jpg
 

hj

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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.
 

djbabyk

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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.
 

Redwood

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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!
 

hj

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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.
 

Wayne in Gville

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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.

washer_rough_b.jpg

Redwood, can you explain the function of the part I circled in red?

washer_rough_b question.jpg
 
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Terry

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That is the vent. The UPC code require that the washer p-trap and standpipe gets vented before dropping below the laundry sink plumbing.
UPC doesn't allow wet venting of laundry trays and washers.
All of this is to prevent the traps from siphoning during use. It adds a few dollars and keeps the home from stinking. It's worth it.
 

BYUFan

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I have a similar project coming up, except I'd like to avoid draining the washer into the sink. Forgive the shoddy sketch, but the pencil is the existing washer system and the red is the proposed plumbing for the new sink. I THINK this method is legal, but can anyone recommend a better or easier solution?

Thanks in advance!
 

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Reach4

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Forgive the shoddy sketch, but the pencil is the existing washer system and the red is the proposed plumbing for the new sink. I THINK this method is legal, but can anyone recommend a better or easier solution?
In my marked up version, the pencil and red both are there. I think your way is probably legal, but the washer may blow some water into the laundry sink. That is not so bad, but this would avoid that.
C needs to be a long sweep, and B can be a combo or wye and 45. I think the drain for the laundry sink can be 1.5, but the drain for the standpipe would be 2 inch if new stuff. If preexisting 1.5, it is probably OK. I am not a plumber.
img_3.jpg
 

Eric C67

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Terry,

I am also considering adding a utility sink to my washing machine drain. Is it possible to tap into the drain at the point of the arrow?

Laundry Room.jpg
 

Joseph Grab

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I helped with the plumbing on our church building, and our plumber had us redo all sanitary tees into Y and 45. Also, no tees could lay on their side like the one on the horizontal pipe in the first photo above, laundry tray and washer rough-in. All tees had to be vertical. Would this be up to the newer codes with Y and 45 in place of the sanitary tee at the bottom? Is the sanitary tee for the vent acceptable, would it also need to be a Y and 45, or could it even be a straight tee as it should never have water flowing through it? I imagine it would work even if not up to code, gravity and water flow haven't changed in 6,000 years.
 
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