*New* Bathroom Sink pooling water and draining slowly

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by djroygbiv, Mar 26, 2012.

  1. djroygbiv

    djroygbiv New Member

    Messages:
    2
    Location:
    NC
    Hi there,

    Lots of great info on this site! I've been a lurker for a while but have a small issue that recently came up and I finally registered in hopes that someone might have some thoughts on what might be going on.

    The issue is the sink in our master bathroom is draining slowly. It was a new sink and new piping put in by the previous home owner so I'm 99% sure the issue isn't a clog as it's been doing it since day 1. It's a single vessel (over-mount) sink and the "pooling" of water isn't consistant. Often times it drains ok but quite often it pools up when the water is running. It usually drains relatively quickly and that process can usually be sped up by tapping the drain or swirling clockwise the water. When you do that, it seem to "catch" and drains very quickly which made me think there might be a venting issue. I'm a novice-intermediate DIY'er with little to no plumbing knowledge so I might be way off base with that guess. Everything in the rest of the house works perfectly (including that in the other 1.5 baths) and I don't notice any correlation in the sink draining of either of those 2 are engaged.

    Any thoughts or guesses around what might be going on? Thanks in advance for any info and help!

    *EDIT* I've added a pick of the plumbing under the sink in case anybody sees anything weird there. The vent is in the wall directly behind the wall and goes straight up to our roof where the "exhaust" vent is. It's hard to tell in the pic but that white pipe on the left that goes up and end is capped with one of those black screw-in caps in case anybody is looking at that. sink.jpg
    Last edited: Mar 26, 2012
  2. Hammerlane

    Hammerlane Member

    Messages:
    263
    Location:
    Ohio
    If the vent is in the wall, there is no need for the"one of those black screw-in caps" which is most likely an AAV or Air Admittance Valve.

    Why not flip that p-trap around and put the high side of the trap on the tailpiece extension. You will be able to cut the tailpiece extension a little bit to reduce some head pressure.

    Attached Files:

    Last edited: Mar 26, 2012
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,263
    Location:
    Cave Creek, Arizona
    It is a poor drain installation, but the problem is the drain fitting in the vessel sink. The sink does not have an overflow passage, so if the water covers the drain fitting too quickly, so the air trapped in the tailpiece cannot escape, and that long tailpipe makes the problem worse because it contains more air, the the water cannot drain until it does escape. When you swirl the water you break the surface tension and let the air out, then the sink can drain. The solution is to make the opening in the drain fitting large enough so that the air and water can move both ways at the same time.

    Slow draining Vessel sink
    The drain below is designed to drain well for a vessel sink.

    [​IMG]
    Last edited by a moderator: Mar 26, 2012
  4. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Among other problems, you have the trap "U" reversed, resulting in a deeper trap, which will be slow
  5. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    Is that a T on its side connected to that "Fernco"?
  6. nukeman

    nukeman Nuclear Engineer

    Messages:
    711
    Location:
    VA
    Also, since the elbow that is connected to the AAV is lower than the wall connection, water is going to pool in the elbow region.
  7. Terry

    Terry Administrator Staff Member

    Messages:
    15,418
    Location:
    Bothell, Washington
    In how many ways does this suck?

    The p-trap is installed incorrectly
    It uses a water tee on it's side
    The AAV is at the same level as the drain
    Does it even need an AAV, or is that an attempt to speed up the draining caused by the lack of an overflow in the sink"

    A grid drain does not work with a vessel sink.
    Here is one that may work better, and they also make some with a pull-up drain cover that allows air to enter the drain.

    [​IMG]
  8. djroygbiv

    djroygbiv New Member

    Messages:
    2
    Location:
    NC
    Thank you all very much for the quick responses and great information. I don't know much about plumbing but I didn't think the under sink plumbing looked right. I didn't know the drain type (assuming it wasn't clog) could make that much of a difference. I've got some work to do to get this corrected. We'll bring someone in that knows what they are doing to make things right for us.

    Thanks again!
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