Loud - gurgling - bathroom sink drain

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by 67stang, Jan 7, 2008.

  1. 67stang

    67stang New Member

    Messages:
    10
    Location:
    SF Bay Area
    Update: Movie! Loud - gurgling - bathroom sink drain

    Hey there,
    First time post. Great forum you have here.

    I am in the process of a bathroom remodel. Vanity/sink are done. We moved the location and therefore tied into the combo vent and drain which serves the shower. For what its worth, work was done by a licensed plumber.

    Got the sink P-trap connected up last night. Right off the bat I noticed the sink drain is very loud. Obviously this is subjective, but compared to other sink drains in the house, this is like running open headers (ok, little muscle car analogy.)

    I have searched the Forums for similar "loud, gurgling drain" threads, and found lots of comments on clogged vents. I am ruling this out since the tub drain (shares the same vent) is NOT loud - fairly silent actually.

    http://www.youtube.com/watch?v=pIyaks3iWsk

    Some other facts - not sure if they relate to the problem -

    There is a long drop from the bottom of the sink to the P-trap - I'd say 25" of 1 1-1/4" tail piece into 1 1/2" ABS.

    The tub/shower is "dry" in that we are tiling the tub surround and therefore haven't run it in a while. Not sure is this effects the sound from the shared vent/drain.


    I dont have too many pics here at work, but can certainly take more tonight and even a video/audio.

    The pic below however gives some insight into how the vent was tapped into. Below the center cabinet, but not visible in this picture unfortunately, is the drain where then taps into the shower drain below the sub floor.

    All the walls are closed up now.

    Thanks in advance for any help.

    Attached Files:

    Last edited: Jan 7, 2008
  2. Herk

    Herk Plumber

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    Location:
    S.E. Idaho
    Please say this is a joke. Why would you tear off all the walls only to have a two-foot drop to the trap? Where do you find a 1-1/4" tailpiece 25" long?
  3. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,309
    Location:
    Yakima WA
    The drop to the P trap is too long. 24" is max. The trap should be right under the sink anyway.
  4. Redwood

    Redwood Master Plumber

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    Location:
    Connecticut
    Got any questions on the tub as long as your here??? Better now than later! And yes the dry tub can add to the sound of the sink but most of your noise is the long tailpiece. What is that on the top left section of the ABS?
    Last edited: Jan 7, 2008
  5. 67stang

    67stang New Member

    Messages:
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    Location:
    SF Bay Area
    Herk
    It's not a joke. The walls weren't exactly tore off...that area was a closet and a shower stall that was removed - walls were open. Since we didn't have the exact vanity and sink dimensions known when the plumbing work was done, the drain was placed in a fairly standard proximity to the waters.

    Redwood,
    To the left looks like a T that is capped. Can't explain why he did it like that, may just have been what he had in materials. Cant imagine this would effect the sound.


    I will measure tonight the actual distance from bottom of sink to the P. I guesstimated 25", but pretty sure that is max - may be a bit less. I certainly didn't find a 24" lon tail piece. I used a 12" long piece attached to the one that comes with the faucet. Now that I think about it, probably way less than 25"

    I ran the 12" long tailpiece considerably deep into the "P"
    Maybe this is causing a flow and hence sound issue?


    Like I said, the walls are closed up now and tub surround is being tiled. Nothing really changed on the tub side for drainage. So, no questions on the tub at the moment.

    Thanks
    Last edited: Jan 7, 2008
  6. 67stang

    67stang New Member

    Messages:
    10
    Location:
    SF Bay Area
    Redwood

    are you saying it is better to have the shortest drop possible to the P, and then put any long drops after the P and to the drain? I could probably plumb it that way and get the P way up there, but would end up with an ABS drop down to the drain of maybe 15" (again, need to confirm these lengths). Would this approach be better for sound control?
  7. cwhyu2

    cwhyu2 Consultant

    Messages:
    1,331
    Location:
    Cincinnati OH
    According to the code that I worked with it was no morethan 24"to the top of the trap.No mater the size of trap.
  8. 67stang

    67stang New Member

    Messages:
    10
    Location:
    SF Bay Area
    okay here is a pic. I exaggerated, the tail pipe is only 12" to the P.

    So, looking at this pic, any major flaws that would cause the massive gurgling?

    Attached Files:

  9. Redwood

    Redwood Master Plumber

    Messages:
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    Location:
    Connecticut
    What is the distance for the sink drain to the water in the trap? Is there water in the bathtub trap or, is it dry?
  10. 67stang

    67stang New Member

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    Location:
    SF Bay Area
    redwood
    i figure 14" from sink to water in P.
    tub drain - i poured a half gallon down it yesterday.

    thanks
  11. cwhyu2

    cwhyu2 Consultant

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    1,331
    Location:
    Cincinnati OH
    That will work.My first hot rod 1969 mach1 shaker hood scoop 351W.:D
  12. one more thing to try. The horizontal slope of the tailpiece (the black pipe and fittings) should be close to flat. About 1 or 2 degrees, not slanted much. This is hard to see with the angle in this first picture. Too much slope and you get noises that keep on noising, like gurgling and then like water dropping. This is independent of the distance drop from the sink to the P trap.

    David
  13. 67stang

    67stang New Member

    Messages:
    10
    Location:
    SF Bay Area
    David
    Not sure I understand... isn't the tail piece the white piece?
  14. 67stang

    67stang New Member

    Messages:
    10
    Location:
    SF Bay Area
    Last edited: Jan 7, 2008
  15. i think the gurgling happens when air mixes with the water -- because the drop is too much and so water speeds through the trap in a turbulent flow, and air comes bubbling back through the water seal of the trap. So, if you loosen the slip joints and push the trap lower, that will increase the height of the seal (the quantity of water sealing the trap) and that may help a little or a lot. To fix the real problem, you have to open the wall and rebuild the pipes in the wall so that the San-Tee connection in the wall is much higher. That is a huge amount of dust and stress for the average family. Unfortunately you cannot do any thing else that is an "intermediate" solution involving less hassle; you cannot raise the trap alone and then make its tailpiece go downwards. Or, you shouldn't and no-on will say it is code or right.

    that is my take on this.

    david
  16. 67stang

    67stang New Member

    Messages:
    10
    Location:
    SF Bay Area


    David
    I agree with your statement that the noise is due to turbulent flow of water. But I don't understand your idea of pushing the p-trap lower. It seems contrary to the previous recommendations of having it as close to under the sink as possible - e.g. reduce the tail pipe length.

    The sink drains very fast, so definately no clogs or vent pipe issues in my opinion. I really think the sound is due to the right (or wrong) combination of sink, sink design, tail pipe, abs P trap, etc. I am tempted to pull out the drain plug piece and modify it so the water flow is less turbulent - more spiral.
  17. don't raise the P trap unless you are going to do it right.

    Everything I have said agrees with the other posts. The P trap should be closer, but it isn't, and so far nobody has told you how much work it will be to do it, and I did. That is the only difference. Before you raise the Ptrap, try a couple other things.

    Now I'll say everything twice: you cannot raise the trap alone and then make its tailpiece go downwards. To raise the P trap, you have would have to redo the pipes in the wall too. First, try other things. First.

    David
  18. 67stang

    67stang New Member

    Messages:
    10
    Location:
    SF Bay Area



    David
    What are these elusive "other things" i can try? :cool:

    thanks
  19. Redwood

    Redwood Master Plumber

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    Location:
    Connecticut
    Pour some water in the tub trap if its dried out!
  20. Nate R

    Nate R New Member

    Messages:
    472
    Location:
    Milwaukee, WI
    I wonder what would happen if you used the 1 1/4" P trap that often comes with sinks instead of 1.5" ABS? I'm wondering if the size of the trap is making it much worse.
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