What is my bathroom sink smell?

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Every morning a foul smell emanates from my bathroom sink drain. It does subside once the water has been running and gone down the drain. I have taken the plumbing apart and cleaned it thoroughly, I put odor sticks down the drain every month, have used baking soda+vinegar, drano but nothing helps. Have had a plumber, contractor and the water department look at it, but no one can figure it out. The plumber says just to close the drain, put water in the sink, then let it drain out, which does work. It is only in the upstairs bathroom sink, but no in any other sink/shower/tub. Does anyone have any idea of what it could be? Thanks.
  15 answers
  • Kelly Condie Thompson Kelly Condie Thompson on May 06, 2017
    Are you on a septic system? If so, your septic tank probably needs to be cleaned out. If not, it could be just the smell from the natural odors in the water. If your water tastes bad, too, consider getting a water softener. That will get rid of the foul smell and taste, too.
    • Greene34 Greene34 on May 07, 2017
      Thanks Kelly, I do have a septic tank that was cleaned not that long ago and the water tastes just fine - I have good water here. But I think it would be a good idea to call the septic company, even though this is the only sink that has this odor.
  • Caseyem11 Caseyem11 on May 06, 2017
    you have a trop for your sink that is dry. If not filled with water nasty smells come into the room. Mine is on the bathroom floor.
  • M Freier M Freier on May 06, 2017
    Do you have a floor drain. Is it full of water,? If not put water in once a week. I lived in a condo and to do that once a week. That took care of the sink smell.
    • Greene34 Greene34 on May 07, 2017
      My sink drain is not on the floor, but goes into the wall that then is connected to the first floor bathroom pipes. The downstairs bathroom sink never smells! Thanks for your advice though
  • Serai Serai on May 06, 2017
    You might contact your local department of environmental quality to have them test your water. If it's something in the water, they will be able to find out.
    • See 1 previous
    • Serai Serai on May 07, 2017
      Ask a plumber about putting a camera down the drain to see if they can see anything (if they haven't already done that). That's odd that it's just that one drain. Maybe a mouse got into the drain and died and is stuck? (Shooting in the dark here lol!)
  • Kristi Smith Grogan Kristi Smith Grogan on May 06, 2017
    Sometimes there is a vent that goes out side that lets gasses escape. That might be clogged and that's why the smell is coming back in the house.
  • Pat Pat on May 06, 2017
    Sinks have U shaped plumbing traps that stay full of water... That is to keep sewer odor from coming back up to your sink. For some reason this U is drying out.
  • Kay McKean Kay McKean on May 06, 2017
    if you are in a single house (not condo) make sure your stink pipe on the roof is not clogged. Could be leaves or critters.
  • Kathy Kathy on May 06, 2017
    My grandmothers bathroom sink smelled like this, then I moved into a house with a smelly sink. The overflow drain - high on the side of the sink - was clogged. Sometimes you can unclog it, but mine was rusted shut at the bottom where the overflow drain emptied into the outflow pipe. I had a new sink put in. Smells great now. Sinks don't cost that much - I have an extra one if you are in Ohio.
    • Greene34 Greene34 on May 07, 2017
      Hi Kathy, Sadly I have no overflow on this sink which is all part of a sink/counter configuration.
  • Kyle Sato Kyle Sato on May 06, 2017
    I am assuming the smell is from bacteria either getting wet or drying up. Probably in the popup assembly or overflow drain or even small cracks. You need to kill the bacteria. Try bleach, pour it directly into your drain & in your over flow drain(thats the small drain hole near the top of your basin) and any cracks. any sitting water may dilute the bleach. Vacuuming or blowing out the drain previous to bleach would be best. this should solve the problem, but may not be permanent. if the smell returns you will have to do it again
  • Kyle Sato Kyle Sato on May 06, 2017
    continue from my previous post.
    what its Not!
    1.its not p trap drying over night(how could this even happen)?
    2.its not a clog(he said he cleaned it out)
    3.its not the vent line leading to the roof(the vent is after the p trap)the p trap prevents smells from coming from sewer system.
    4.its not the vent line being clogged(the purpose of the vent line is to get around the straw effect, If u cover the end of a straw and lift it out of your drink the water remains in the straw) the vent is after the p trap which prevents sewer gas from entering your home. if its sewer gas you got Real Problems.
    5.its not his water. he said all his other drains have no problem and the water dep came out to check it already.

    It is Bacteria! kill the bacteria and i guarantee your problem will be solved.
  • Judy H. Judy H. on May 07, 2017
    Call a different plumber or your city health department.
  • Ava Cone Ava Cone on May 07, 2017
    I have had this same problem in the master bath, I finally poured some white vinegar down it, and it corrected the problem, it has been over a yr. now and I have had no return. But I do keep the vinegar on hand.
  • Pat Pat on May 08, 2017
    If we do not use our bathtub for a long while, we will get a drain smell....we just pour some water down it and the smell goes away.....I thought it was just the P trap or U pipe that had dried out. But if you use the sink every day, that should not be your problem.....I would check that the p trap is okay and pour some bleach down it.....may have to do it once a week. Have a plumber look at it when he is there some time. Even though your sink connects to the one down stairs, I think, but not sure, that it should have a p trap or u pipe under this drain also.
  • Greene34 Greene34 on May 08, 2017
    Thanks Pat, I do use the sink every day and yes, the smell goes away once water goes down the drain. I am going to give the Bleach idea a try tonight.
  • Eileen Crosby Eileen Crosby on Oct 15, 2017
    I’ve solved this in my bathroom sinks and stand alone shower by running hot water down drain, then pouring Blue Dawn Dish soap into drains and then repeating hot water. Most often the build up and smell is slimy gunk from toothpaste, soap, conditioner (in shower). In shower, I remove drain plate once a month and use an untwisted wire hanger keeping the hang hook on the end. I put it down the drain and pull up a hair ball that gets trapped in the pipe. The smell is awful once the hair comes up. It goes right in trash and out to bin. Give it a try. Bleach in septic systems may break down the enzymes that are necessary for keeping your system working as it should.
    • Greene34 Greene34 on Oct 16, 2017
      Thanks Eileen. I will try the Dawn trick. I have already taken apart all the drain pipes under the sink and cleaned them very well, but that didn't seem to help. Maybe the problem is further down. I did try bleach, which helped for a few days but don't want to keep pouring bleach down my drain for the reasons you mentioned. So maybe Dawn will be the answer! Thanks again.
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