Can the 2" drain from the washer be connected directly to the long turn combination tee/wye and eliminate the vent connection between the sink connection and the 1 1/2" sanitary tee?


  • I'm voting to reopen. See Ecnerwal's comment on FreeMan's answer. I misinterpreted the question.
    – isherwood
    Feb 15, 2023 at 17:28

2 Answers 2


section of example layout given with part redlined

It would be preferable to get a picture or drawing of your actual layout and whatever contraints you think you are up against in terms of running pipes. In some cases the answer will be that you need to re-think your layout to fit your constraints, in order to meet code (and not stink!)

The pipe circled in red is functionally non-optional, as it serves to vent the sink (lavatory) drain here. The auxiliary vent loop to the left of it may be optional, depending on details of your actual layout and your applicable plumbing code (they do vary.)

So long as you preserve the function, the location can be varied (may require using larger pipe where "wet venting" though.) You could vent this layout like this, if that particular location was an issue:

Moved Vent

But that example image is not your actual install, so it might or might not be useful to you - which is why a diagram or picture of your actual install is helpful.

  • Yup, I think this is a better answer to the actually asked question.
    – FreeMan
    Feb 16, 2023 at 17:19

If I've correctly identified what you're asking, then I believe the answer to your question lies within the picture itself.

enter image description here

Note where that horizontal run from the laundry P-trap is labeled 60" or less. So long as it's less than 5 feet from the trap to the vent connection, you can connect it anywhere you want.

  • This is the key, and it's the reason for the side loop in the vent in many cases. Here, however, it's not needed as the distance to the primary vent stack is less than 60". It was probably added to clear the sink drain.
    – isherwood
    Feb 14, 2023 at 19:20
  • 1
    The auxiliary loop is not needed if the drain is short enough, indeed. However, the section circled in red on the original picture is not auxiliary. it's the upper part of the stack, and removing it leaves the sink unvented.
    – Ecnerwal
    Feb 14, 2023 at 19:46
  • @Ecnerwal, you've highlighted question intent that I missed or misinterpreted. This answer doesn't address that, nor does my comment. Good catch. Post an answer.
    – isherwood
    Feb 15, 2023 at 17:27
  • I agree. I quite missed that part of the question, as well.
    – FreeMan
    Feb 15, 2023 at 17:59

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