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sewer smell from running water bathroom sink only after flushing toilet

ron
ron Member Posts: 148
2 story house, city water/sewer.

The master bedroom bathroom, on the 2nd floor, is a typical smallish bathroom where the sink is arm's reach from the toilet.

Only after #2 in toilet after flushing, you wash your hands in sink and get a smell of sewer gas or p00p smell. But it is only when you begin to run the water in the sink that you get the smell. If you don't use the sink and just flush the toilet, everything is fine no smell (from the sink). And getting home 6 pm, when no one has used toilet all day, you can run the water in the sink and there won't be a smell.

This has never happened before, and is only happening at this location, not in either of the other 2 bathrooms, and only started maybe 3 month ago.
Can the trap cause this, and should i just replace the trap, or what else can be done?

Comments

  • rick in Alaska
    rick in Alaska Member Posts: 1,244
    Very confusing. Typically if it is a dry trap, which depending on how it is plumbed and vented, you would get the smell before you run the water in the sink, and it would go away after you run it. Is the smell definitely coming from the sink?
    I am thinking maybe a cracked pipe that has sewer gas being pushed out of it as the water in the sink drains, but this is a long shot. Is the piping plastic or cast iron?
    I can't think of any reason to replace the trap. It is just a pipe that holds water, and unless it is leaking, it should be fine.
    You might have to have someone come out and introduce smoke in to the piping to see if it is leaking sewer gas.
    Rick
    Zmanmattmia2
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,354
    Sometimes you get mold or other smelly stuff in the sink overflow. Just something to check
    rick in AlaskaLarry Weingarten
  • pecmsg
    pecmsg Member Posts: 2,345
    Rotten egg smell from the Hot Water?
    ronbugg
  • Jamie Hall
    Jamie Hall Member Posts: 17,132
    You may have a clog in the plumbing and, oddly, the clog may be above the connections, in the vent, as well as or instead of a clog in the lines below.

    This requires really paying attention to the timing of the smell. I would be particularly suspicious of a vent clog if the smell was evident when you first start running water in the sink, and then cleared up.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Derheatmeister
  • Zman
    Zman Member Posts: 7,001
    The best way to troubleshoot this is with a smoke test.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • ron
    ron Member Posts: 148
    after pulling the trap i could smell it in the sink basin,
    turns out is was goop build up in the sink overflow channel and was located just under the stopper where the overflow channel exits into the sink drain. Ran the garden hose up through the window and blasted it all out. all better now.
    SuperTech
  • ChrisJ
    ChrisJ Member Posts: 11,978
    ron said:

    after pulling the trap i could smell it in the sink basin,
    turns out is was goop build up in the sink overflow channel and was located just under the stopper where the overflow channel exits into the sink drain. Ran the garden hose up through the window and blasted it all out. all better now.

    Why would flushing the toilet have anything to do with that?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    mattmia2Grallert
  • JUGHNE
    JUGHNE Member Posts: 8,972
    Because of course, everyone washes their hands, especially after #2 delivery....I think that running the water down the drain would activate the goo in the drain and release nasties.

    Every overflow in lavs get an accumulation of something. Usually no water goes down the actual overflow port to rinse anything away. Especially toothpaste which seems to clog things by collecting hair in the drain.
  • Intplm.
    Intplm. Member Posts: 1,336
    You may want to check the over-flow hole on the fixture as mentioned below. It might be very dirty internally and be the cause of this.
    Using a good quality liquid grain cleaner repeatedly might cure this problem.
    JUGHNE said:

    Because of course, everyone washes their hands, especially after #2 delivery....I think that running the water down the drain would activate the goo in the drain and release nasties.

    Every overflow in lavs get an accumulation of something. Usually no water goes down the actual overflow port to rinse anything away. Especially toothpaste which seems to clog things by collecting hair in the drain.

  • Kickstand55
    Kickstand55 Member Posts: 32
    Using a Bio-Enzyme product in all traps, drains and toilet tanks absolutely will remove and keep the goo away.
    I have been selling the product to my customers for years. It actually cleared up a couple of leach beds that were thought to have failed.
    The company is in Dane, WI. I won't mention the name due to a possible conflict of interest.
    I have found vents partially of completely clogged causing reversal of sewer gasses, slow drains etc. Sometimes a infrequently used trap will dry out and provide a venting effect until filled again. This can throw off the diagnosis and leaving all involved scratching their heads or heading to the bar room for advice. :s
  • psb75
    psb75 Member Posts: 479
    Glad the problem got solved. Odd though given that "toilet flush, then gas smell at sink" didn't prompt a question about whether the sink trap was a "P"-trap or "S"-trap (which stands for "siphoning").
    Canucker
  • jumper
    jumper Member Posts: 1,715

    Sometimes you get mold or other smelly stuff in the sink overflow. Just something to check

    What can be done about this?
  • ChrisJ
    ChrisJ Member Posts: 11,978
    jumper said:
    Sometimes you get mold or other smelly stuff in the sink overflow. Just something to check
    What can be done about this?
    I plug the drain and fill up the sink once in a while and fill it until a good amount of water dumps down the over flow.  I do this on the tub as well.

    I also like to do this because when I open the drain it flushes things out good.  Much better than trickling water when someone showers or washes their hands.





    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    Canucker
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,291
    Hi, For a smelly overflow, I make a funnel from paper and pour down some hydrogen peroxide. Really flood it. Works nicely.

    Yours, Larry