I am installing a new washer box. (see picture for reference) My plan was to switch out the Wye from the sink so the top was 2" and put the p-trap and Wye from the washer just above that in the stack. Then reattach the vent to that. My buddy was making a comment that a washer Wye has to go below the sink Wye in the stack.

As you can tell doing so would be a bit of a pain given the position of both appliances. I will say I'm not up to par on the plumbing codes (pretty sure he isn't either).

Is there any reason that I cant just fit in the washer above the sink Wye?

Location is Virginia.

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You'll need to change the tee on the vertical pipe to a 2" tee for the laundry drain. You're not allowed to reduce to a 1-1/2" for a few inches of horizontal branch and then increase to 2" again for the washer trap & standpipe. However, the washer trap & standpipe does need to be minimum 2".

PEX crimp connectors certainly can be behind drywall. Check with your AHJ if you have any doubts about your local rules, but these are reliable connections.

You are probably going to need to reroute the copper supply pipes to fit the laundry trap in that wall cavity. Keep in mind there are several height restrictions on laundry standpipes. It must be >= 18" above the trap weir and 30" to 48" above the floor. The trap itself should be >= 12" above the floor.

  • 1
    Thanks for the info! Yes for the stack my plan was to change out the sink tee for a 2" vertical and a 1 1/2 side to match the sink now. Above that in the stack would be another tee with 2" openings linking to the bottom of the stack and to the side for the washer, 1 1/2" top to match the current vent.
    – James D
    Nov 26 '20 at 18:58
  • I have plenty of room to go up if needed. was trying to stay at a reasonable height anywhere below 96" which is what the washer specs say the max for the drain can be.
    – James D
    Nov 26 '20 at 18:59
  • I think I understand your planned configuration. You may need to move the box up higher and do a 45-45 jog to the left to make the trap fit into that stud bay. A Sioux Chief Ox Box with the supply on the left of the stud & drain on the right would be easier. Check it out before you make a final decision. Ox Box would still have to be higher than the current one (for standpipe minimum height above trap weir) but the drain configuration would be simpler. Nov 26 '20 at 20:57
  • Think i found the box you speak of. Looks like 2 separate boxes that wrap around a stud. supplies on the left box and the drain in the right box? Ill see if one of the local stores have one. So in regards to my original question about if the washer tee can be above the sink tee, is that allowed or is my buddy right and the washer tee has to go below the sink tee?
    – James D
    Nov 26 '20 at 21:09

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