Sanitary tee on back for venting toilet

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by bandrewfox, Jul 22, 2012.

  1. bandrewfox

    bandrewfox New Member

    Jul 22, 2012
    Hi, I'm a new member here and have been browsing the forum trying to get an answer to this question, but it seems like half the threads say it is ok to do this and half say it is not ok.

    My question is: can I use a 3" sanitary tee on its back with the 2" opening going straight up vertically (as a vent - with nothing draining into it) on a horizontal 3" drain directly from the toilet's floor flange (about 1 foot away from the san tee)?

    I certainly understand that san tees can only be used vertically for drainage, but is this considered drainage or venting? Toilets seem to be an exception to some rules because their trap is inside the fixture...

    If you say "no, san tee cannot be used in this situation", then I will have to use a wye for the 2" vent - but I can't use the wye with the 2" vertical since there is not enough room in my joist area for the extra street 45 fitting. In this case, my next question is, how much do I need to "roll" my wye. Does it have to be 45 degrees or is something like 10 degrees ok? I know it can't be flat.

    I am the homeowner doing the work and this is in Seattle - with King County doing the plumbing inspection.

    Thanks so much!
    Last edited: Jul 22, 2012
  2. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Aug 9, 2009
    If the sanitary tee is down stream from the toilet it's OK.

    Last edited: Jul 22, 2012
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  4. Terry

    Terry Administrator Staff Member

    Aug 17, 2004
    Bothell, Washington
    In Seattle, which uses UPC code, they will expect a combo or wye fitting if it's on it's back.
    You may need to drill a larger hole up through the floor. can try the Santee and see if the inspector notices.

    Here is a nice link to Bert Polk's plumbing tips
    Last edited: Jul 23, 2012
  5. Tom Sawyer

    Tom Sawyer In the Trades

    Nov 29, 2010
    Downstream or there is waste upstream and the 2" straight up works for IPC
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