Laundry Room Drain

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Brent S, Dec 6, 2009.

  1. Brent S

    Brent S New Member

    Messages:
    4
    Location:
    Montreal
    Hello everyone,

    This is my first post here and I hope you can help me. This past week A contractor put in a floor drain in my laundry room. It has a P trap and a backflow vallve on the line. Here is the problem....I am smelling sewer gases from the drain. The stand pipe for the washer drain is also smelling. I realize that this pipe will cease smelling once the washer is connected and there is water in the Ptrap, but how about the floor drain. With no water flowing through it, unless the washer leaks, how can I protect against sewer smells coming up through this drain?
    Last edited: Dec 6, 2009
  2. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    pour a cup of vegetable oil down it.
  3. FloridaOrange

    FloridaOrange Plumbing Designer

    Messages:
    1,317
    Location:
    SW Florida
    Ideally the floor drain would have a trap primer serving it. The primer could be a valve type or many times it comes off of the trap serving a fixture in the room. In the latter case it would take use of the fixture (washing machine in your case) to "prime" the floor drain.

    If there isn't a trap primer of some sort you will have to put water in every so often. The veg. oil mentioned above will keep the trap from evaporating for a while.
  4. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    Years and years actually.
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,313
    Location:
    New England
    You have a choice...sewer smells or rancid cooking oil smells. Or, make a habit of pouring a cup of water down the floor drain every time you wash clothes. RV antifreeze would work for awhile and not smell.

    Maybe it's just me, but I don't use oil often enough, even in small bottles, and it smells and I chuck it before the bottle is empty. Sitting open to the air would make that happen faster.
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,247
    Location:
    Cave Creek, Arizona
    drain

    I use antifreeze which will stay there forever, or until the floor has water on it to flush the antifreeze away.
  7. 4chi

    4chi New Member

    Messages:
    2
    Location:
    Colorado
    I have this problem, but water down the drain hasn't fixed it.

    We moved into this new house in October of 2011. We had a few random days of sewer smell from a main floor laundry floor drain during the winter, but I thought nothing of it. This spring/summer it got worse. It usually seems to happen in the afternoon.

    We had plumber come out, he told us to pour some water in the floor drain. We did that, and it seemed fine for a week, but the smells came back. I can see water in the bottom of floor drain, and its level has not seemed to change. I've been adding water on a daily basis to see if that helps, but no. Yesterday, man, that was the worst stench ever, and it seemed to get worse after I poured some more water into the floor drain.

    The plumber is coming back out on Saturday to check it again. I'm worried about a sewer line backup that is getting sewage back into the that trap. This is a new house, but it was a scrape, and the sewage line has probably been in place for 40ish years. When the stink is bad in this laundry room, I've also been checking to see if I can smell it anywhere else in the house. A couple of time I thought I could smell it in an upstairs bathroom, but I could have been imagining it. It doesn't seem to make sense to me that I'd smell it in in upstairs bathroom and not a downstairs bathroom.

    Anything else that you all could think of that could be causing this issue? Anything else I should try?
  8. bigjohn2012

    bigjohn2012 Big Canadian

    Messages:
    3
    Location:
    Brampton Ontario Canada
    HJ - you use antifreeze? i have never heard of that technique before..
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,247
    Location:
    Cave Creek, Arizona
    Antifreeeze does not evaporate, so it stays in the trap until something washes it away.
  10. 4chi

    4chi New Member

    Messages:
    2
    Location:
    Colorado
    Problem solved (I think). We converted this laundry room into a mudroom when we moved in. It now has four big Ikea "lockers" for each family member. But it still has a washer drier hookup and a washer drain pipe behind one of the lockers. I moved out the locker and sure enough, they had not sealed over the washer drain when they installed the lockers. So while the room certainly stunk before from case coming out of the floor drain, I think it was still coming in from this dry trap on the washer drain.

    I poured some water down there to fill the trap. I'll either figure out how to seal it or maybe go the anti freeze or oil route, or maybe just slide out the locker and refill it with water once in a while. Something makes me hesitate to to pour oil or antifreeze down there.

    Oh, and I think it happened mostly in the afternoon because that is when the AC kicked on, and it was sucking air from wherever it could, including this pipe.

    Let's hope this has it solved.
  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,247
    Location:
    Cave Creek, Arizona
    In that case, I would also check where the AC's condensate drain is connected, because that is also a prime source of sewer gas odors.
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