Funky-ish odor in kitchen sink

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by CindyJ, Jul 8, 2014.

  1. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    About 3 months ago, we had a kitchen renovation completed. Included in the renovation were a new double-bowl sink and new dishwasher. The new sink is about 24" from where the old sink was situated, so the sink plumbing was shifted accordingly.

    About two weeks after all was completed, I started noticing a strange odor at the sink. This odor did not exist before the renovation. It doesn't smell like rotten food and it doesn't smell like a decaying animal. It's hard to describe it except to say it's mildly funky. At first I thought it was coming from the dishwasher, but I notice it even when the dishwasher is closed. Another thing I should mention is that after the water has been running for a short while, I no longer notice it. Maybe my sense of smell is just adapting to it, but it seems to go away when the water runs. It might be relevant to mention that I do not have an under-sink garbage disposal.

    Can anyone help me identify the likely source of this odor? And, more importantly, help me get rid of it. Thanks!
  2. Reach4

    Reach4 Well-Known Member

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    2,817
    Location:
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    See if http://terrylove.com/forums/index.php?threads/swampy-sulfur-smell-from-upstairs-faucets.57569/ helps.

    Maybe run a quart of hot and a quart of cold into separate containers. Take them away from the sink. Smell each container, or better yet, get a young nose to smell. If there is a difference in smells, look to the plumbing. If the problem is more with the hot, you could try raising the hot water heater temperature for a while. Then run hotter than normal water slowly from the tap. Then put the water heater temperature back to normal. If you have a tempering valve, that could prevent extra-hot water from making it to the faucet.

    It could also be the sink trap. A little bleach solution down the drain slowly could help that. Does your sink stopper leak just a little? If so, put about 1 gallon of water into each stoppered bowl of your sink. Put a tablespoon of liquid chlorine bleach into each bowl. That corresponds to a little over 200 ppm chlorine. Stir with a spoon etc. Let the water trickle down the drains. If the bowls have not emptied in an hour, help it along. Avoid holding your hand in the bleach water. If you do get the solution on your skin, probably no reaction will occur, but rinsing in a different sink would be reasonable.

    I wonder if your city water does not have residual chlorine by the time that it hits the kitchen faucets. Particularly the hot line might be almost chlorine-free. I don't think I have heard that discussed. With a well, people routinely disinfect their pipes and faucets if they sanitize their wells (after well work, and for some people maybe biannually). Some high sensitivity chlorine strips, such as a pool store would have, could check for that. Note that this is not normal test, but I think I would do it if I had musty smells coming out of the faucet. I am not a pro. I don't think this is standard advice. I have a well that I have sanitized. Whoopee.
  3. presence

    presence New Member

    Messages:
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    Location:
    Here and Now
    I suspect you have something in your trap; some eggs or something. Fill the sink to the top... then let it drain out to flush your trap clear.
  4. Terry

    Terry Administrator Staff Member

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    15,422
    Location:
    Bothell, Washington
    Did you install deeper sinks?
    Can you post a 800 pixel or less picture of how it's connected?
  5. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    The new sinks are pretty much an updated version of what I had previously. My husband thinks it might have something to do with where the dishwasher is connected in relation to where the trap is. I hope this photo gives you a good idea of the plumbing configuration.

    And FWIW, we have well water with an inline filter and a septic system.

    [​IMG]

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  6. Smooky

    Smooky Member

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    NC
  7. Terry

    Terry Administrator Staff Member

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    15,422
    Location:
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    Your S-Trap is siphoning.
    Also, the dishwasher needs to be installed with either a high loop, or an air gap. Right now, with some dishwashers, the sink can backflow into your dishwasher. Yuch! :(

    Here is a small sink with an AAV for venting.

    [​IMG]


    [​IMG]


    [​IMG]

    The sink drain is run with 2", and the p-trap is 1.5"
    The AAV is higher than the trap arm.
  8. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    Thanks so much! This is all very helpful.
  9. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    To follow up... I had a lengthy conversation with the plumber who did the work in my kitchen renovation. He doesn't seem to think that an AAV will solve the problem because he feels it's more likely caused by a clog in the venting somewhere in the house.

    I had forgotten until he reminded me that the first time the water was turned on at the kitchen sink, the water did not drain. After a bit of aggressive plunging, a mess of yucky black stuff came up and then drained. Since then the sink has been draining just fine (as far as I can tell). The plumber is guessing that there's another clog somewhere in the system. He also said that adding an AAV under the sink would mask the odor, not prevent it, and that the odor could well show up somewhere else in the house, most likely in the laundry room or the powder room, both of which are fairly close to the kitchen. He also said that the only way to be sure there's not a clog is to bring some kind of equipment to the house that's made for clearing sewer systems, to go up to the roof where the main vent comes through and run the equipment. He said that other, larger plumbing companies have equipment with cameras that enable the plumber to actually see inside the pipes, but he doesn't have anything like that. I hope I'm describing this correctly and that this is making sense.

    So I'm not sure where to go from here. The plumber isn't pushing this as a solution he wants to sell to me; it's just his best guess as to what's causing the problem. He also said if we did want him to do this, he really can't estimate what this would cost because he can't say how long it would take to do the job. And, since this isn't directly caused by the renovation per se, the cost wouldn't be covered by the warranty I received from the general contractor. I wish there was a way I could troubleshoot the problem to know the best, surest, most cost-effective way to approach the resolution.

    I need some guidance -- how should I proceed from this point? Thanks!
  10. Terry

    Terry Administrator Staff Member

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    15,422
    Location:
    Bothell, Washington
    For starters, take the advice of a plumber of 40 years, not the hack that installled your plumbing.

    What you have is an S-trap, an ilegal S-trap at that. Pull a permit, and the plumbing inspector can clue in your handyhack.
    That needs to be replumbed with an AAV or, run it proper and vent through the roof. Your handyman's excuse is one for the books. His premise that if you vent something proper, the problem just shows up somewhere else. How did he come up that bit of nonsense?

    [​IMG]

    The wrong way to plumb a kitchen sink.

    Also, take the dishwasher hose and at least strap it up high in the cabinet so that the goo from the sink doesn't flow downhill into the dishwasher.
    In Washington State they like an above the counter Air-Gap for those connections.

    [​IMG]

    Next time you talk to your "plumber" get his license number and check if he's registered with the State.
    Someone needs to clue this guy in.
  11. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    Terry -- thanks once again for your input. My husband did hang that dishwasher hose higher in the cabinet, so that shouldn't be an issue. Just a bit of clarification on a few points, please. (1) You say to, "Pull a permit and the plumbing inspector can clue in your handyhack." I don't understand what you mean by "pull a permit." But that has me wondering -- I'm sure permits were obtained for doing the electrical and plumbing work for the renovation. So wouldn't the plumbing had to have been inspected at some point? (2) Are you suggesting that the main pipe configuration is not only wrong, but illegal? Is the double-curved pipe configuration the "S-trap" you referred to? And (3) My sink is in a peninsula that sits in the middle of the first floor of a 2-story home; how is it possible to vent it through the roof?
  12. Terry

    Terry Administrator Staff Member

    Messages:
    15,422
    Location:
    Bothell, Washington
    Pulling a permit is slang for obtaining a plumbing permit from the building department.
    The next step would be for an inspector to look at it, and put his/her signature on it showing that it passed and is a legal way of doing it.
    There are entire books with plumbing codes, that we have to learn before we are allowed to do plumbing. A handyman is someone that bypasses that, because it may take too much book work, or that he can't find an apprenticeship. Typically, that's three years working with a Journeyman plumber (6000 hours) before they can take the State test for licensing. The hope is that somewhere in that 6000 hours, some of what we need to know, gets learned. It's hard to explain to a handy person, that there are certain laws of physic and hydralics that aren't always obvious with only a high school education. It generally takes more education than that. I've worked around both, and I can tell you that there's a big difference in how things get plumbed. And all I can gather from working around them, is they don't know, and don't care.

    There are several ways of plumbing an island sink.
    The way your was done is not one of them.

    The picture below is also of an island sink on a second floor, using an AAV to prevent the trap from siphoning. When the trap siphons, that's when you get sewer odor at the kitchen sink. I think you refered to it as a funky odor.

    Did you come here for an answer, or to confirm that what you have is okay? It's not okay.
  13. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    If my last post came across sounding like I was looking for approval for the plumbing, that was my fault for not being clear enough. I came here to get clarification so that when I call the owner of the company that did my kitchen renovation, I can sound fairly informed. Up until now I've spoken only with the plumber, who is a subcontractor. I know the plumbing is not okay and now I understand why it's not okay. I want to be able to handle this issue intelligently; in my experience, that's how issues get resolved. Except for this plumbing issue, I've been very pleased with the quality of the work that went into my renovation, and also with the integrity of the owner, the project manager and the subcontractors. Mistakes that were made during construction were all resolved to my complete satisfaction. I have every reason to expect that this issue will be resolved as well.
  14. Terry

    Terry Administrator Staff Member

    Messages:
    15,422
    Location:
    Bothell, Washington
    [​IMG]

    One more example of a kitchen sink with an AAV.
    There is a air-gap on the sink, draining to the disposer here. Hammer arrestors on the water supply.
  15. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    The plumber will be here either tomorrow or next week to correct the plumbing by replacing the S-trap with a P-trap. The venting will connect (through the basement) with the main stack that vents up and out the roof. Am I correct in assuming that an AAV would still need to be installed under the sink? (Just a reminder, we do not have a disposal). And the hammer arrestors -- what are they for?
  16. Terry

    Terry Administrator Staff Member

    Messages:
    15,422
    Location:
    Bothell, Washington
    Current plumbing code requires a hammer arrestor for the dishwasher if you have a check valve at the water meter.
    I think your sink will require the AAV for the p-trap.
  17. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    Just to follow up -- Problem Solved!!! To Terry and everyone else who replied to my post and helped me to sound smarter than I actually am regarding plumbing matters -- I cannot thank you enough! The plumber (and a helper) were here. They removed the S-trap, installed a P-trap and installed a Studor AAV. They also did a better job of raising the dishwasher hose than my husband did, even though they did not do the dishwasher installation. Best of all, the owner of the company that did the renovation stood behind his warranty, so the modification didn't cost me a penny. Many, many thanks!!!
    Terry likes this.
  18. Terry

    Terry Administrator Staff Member

    Messages:
    15,422
    Location:
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    Well, I think we can safely say that you are smarter than the average bear now. You learned what needed to happen, and made it happen. Good job! :)
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