Kitchen sink P-Trap location question.

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by kgphoto, Sep 18, 2008.

  1. kgphoto

    kgphoto New Member

    Messages:
    5
    Due to layout changes, that happened before I was asked to get involved, the stub out for the kitchen drain is 24 inches to the side and 13.5 inches lower than the center of the sink drain hole.

    So my question is, should I attach the p-trap at the wall and then go over to the sink (at 1/4 inch per foot rise) and then use a tall tail piece, or should I angle up with sweeps or 45's and put the p-trap by the sink?

    Also, would adding a clean out there be good as once I cement in the ABS you won't have a straight shot into the wall for snaking later.

    I also want to maximize storage room, so raising the pipe up under the sink for the lateral is appealing.

    I wondered if 8 inches of fall in 2 feet would cause a rush of water that might evacuate the p-trap.

    What do you think of adding a clean out wye just before the wall?

    Thanks for any guidance you can provide.
  2. Master Plumber 101

    Master Plumber 101 In the Trades

    Messages:
    268
    Location:
    Wisconsin
    Everything about what you are posting sounds wrong. Please take no offense. The kitchen waste should stub out of wall at 18"-19" above your finished floor. What you want to do will interrupt the vent. If you can send some pics it will give myself and other professionals a better idea of exactly what you want to do.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,240
    Location:
    Cave Creek, Arizona
    drain

    You CANNOT raise the trap no matter how much nicer it would be for your purposes. The trap goes under the sink opening so offset the line with a 45 or other fitting in a horizontal plane and install the trap at the end of it. Here we do not glue the entire system together so there is no problem getting into the wall pipe. If you do cement everything then definitely put a proper cleanout in the line.
  4. kgphoto

    kgphoto New Member

    Messages:
    5

    No offense taken. I didn't plumb this house, I am just being asked by my brother to attach the drain to the sink. The 1 1/2" drain stub comes out 8 inches above the floor of the cabinet, so when you ad the 4" toekick it is about 12 inches off the finished floor.

    He centered the drain in the wall and then set the kitchen base cabinet off center. Once the counter and sink are installed, the bottom of the sink strainer, where you attach the tail piece, is 22 1/2" off the cabinet floor so about 8 inches higher than the drain stub out.

    I wanted to minimize the loss of storage by raising the trap and the lateral, but can't find any info in my books that talk about the height relationship.

    If I understand you correctly, just come over from the stub to under the sink and install the p-trap and then go up with a tail piece. Right?
  5. Terry

    Terry Administrator Staff Member

    Messages:
    14,754
    Location:
    Bothell, Washington
    [​IMG]
    Typical sink drain.
    Where the santee is, that would be the level of the drain.
    If they set it low, that's what you go with.
    I have gone into the wall, and moved the tee when needed.
  6. kgphoto

    kgphoto New Member

    Messages:
    5
    Terry,

    If I have understood you correctly, you are saying to put the P-Trap (drain) at the level of the drain stub out from the wall? Then use the tail piece to reach up to the sink drain (strainer). There is no garbage disposal involved here, a single bowl only. I told him it was bad idea not to have a garbage disposal, but I am only his brother. ;)
  7. Terry

    Terry Administrator Staff Member

    Messages:
    14,754
    Location:
    Bothell, Washington
    Yes, and then use a tail piece vertically to the sink basket.
  8. Good news: you can maximize storage space. So far no one has pointed this option out so I'll do it.

    See http://www.terrylove.com/forums/showthread.php?t=15269 and look at the first line drawing. It is drawn sideways so you'll have to rotate it 90 degrees or lay your head sideways. It shows a tight bend (elbow) under the sink which sends the waste in a straight line (no bends) horizontally over to the point in space just above the P trap. Then, another tight bend sends the waste line down to the P trap. No air, no venting, no standpipe.

    Yes, the P trap must be positioned on the same level as the stub out from the wall. But, the news here is that you can place the P trap right up against the wall if you follow these two bends. This is hardly ever discussed here or anywhere else. I often wondered why. I may never know. But I do know that it makes a very quiet drain so I am one happy homeowner. Also, to reassure you, it seems all the expert plumbers here agree this configuration does not break code. The P trap is at the right height, and one tight bend is allowed under a drain. Just like under a toilet or under a tub.

    Yes, you can include a cleanout Wye in the line too, before the P Trap. Good idea.

    Further down in this thread you mention disposers. There is no need for a garbage disposal. My opinion. Billions of people have none, and live to tell their story. I've never had one and I feel fine.


    David
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,240
    Location:
    Cave Creek, Arizona
    drain

    That configuration will work, but the only time I have ever seen it used is when you have the "space saver" dishwasher that fits under the sink so you have to offset the drain.
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