DWV Connection – Drain to Vent
Hi,
I am wondering if this is an incorrect setup for our drain line and its connection to the vent? I have seen multiple posts online that a wye should not be used in this application, but it should be a sanitary tee. For the plumbers in here, can I get confirmation of this? My contractor, who is not using a licensed plumber but operating under the license of one, is adamant this is sufficient. My understanding is the way it’s setup now with the wye could allow for a strong enough siphon to pull water from the trap and allow sewer gas out the “wrong end.” It also appears to almost make an s-trap, but I think that’s debatable.
Thanks,
Michael
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Replies
Not allowed and likely clearly evident in whatever code you're under. You are correct in saying it should be a sanitee.
Thank you for the confirmation! Glad to know I'm not crazy. Everyone should bear witness to the totality of this plumbing job and let it serve as a guide on exactly how not to plumb a house. It's so sloppy and bad.
Yep, should be a sanitary tee. There is a thread on almost exactly this setup on the Terry Love plumbing site: https://terrylove.com/forums/index.php?threads/best-way-to-wet-vent-a-washing-maching-and-utility-sink.83470/
JLC's field guide for venting may also be helpful here:
https://www.jlconline.com/how-to/plumbing/vents/vents-field-guide
I think you're pretty close to having an S trap here too, but if they replace that wye with a sanitary tee raised up a bit, then they'll probably have enough of a horizontal pipe section to get you back into P trap territory. Basically replace that one fitting, and swap the position a bit using a coupler, and you can fix both issues at once.
Bill
Thank you Bill for the reply and links. They will serve very helpful in my conversation. I also found a plumbing company that will come do a full inspection, so at least will get some peace of mind before everything is covered up and it's too late.
Not a plumber. But the reason a sanitary tee is required there is there has to be a continuous layer of air between the top of the pipe and the vent, otherwise the pipe can get airlocked under heavy flow.
Fixing it is less than $20 worth of fittings and a few minutes.
Thanks DC, that's my instinct too but all I get is pushback when I ask, cause I'm just a lowly homeowner. It's a pattern of behavior from our contractor and we're just safeguarding ourselves from future issues and trying to get to a point where we can let him go.
Thanks