Sewer smell from laundry room

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by jvstevens, Jan 10, 2014.

  1. jvstevens

    jvstevens Member

    Sep 14, 2005
    Every so often, the tenant for my rental reports a bad sewer smell in the laundry room. The laundry room has a utility sink that has its own trap directly beneath it, and there is also a galvanized washing machine drain pipe (exposed...not hidden in the wall) that has its own trap as well. The washing machine actually drains into the laundry tub, not the galvanized pipe (which is unused and not capped). There is also a drain cleanout plug at the base of the wall in the same area. The hole in the wall for the cleanout plug is a bit bigger than pipe, so you can see inside the wall (and likely beyond, into the crawl space...can't say for sure due to poor visibility and access). There is a drain vent on the roof above the laundry room. So, I'm wondering where the smell might be originating from. The two traps (under normal circumstances anyway) should block sewer gasses from getting out. I'm no expert at this, but I can only come up with two ideas:

    1) There is a leak in the drain pipe in the crawlspace that is coming out through the hole in the wall around the cleanout plug
    2) The water in the trap(s) gets siphoned/sucked out occassionally, for some reason, which allows the sewer smell to get through. Is this plausible/possible, and might it be due to a plugged vent?

    Also, is there any problem with just capping off the unused galvanized drain pipe (just to eliminate it as a source of the smell)?

    Any help is greatly appreciated.
    Last edited by a moderator: Jan 10, 2014
  2. ankhseeker

    ankhseeker Member

    Oct 2, 2013
    San Pablo, California
    Many front loading washers contribute to that smell from mildew and moisture behind the seals. I certainly have smelled it from my sisters unit.
    From a DIY'r I don't see why you can't cap it off, but I m sure that a professional will chime in to give a professional opinion.
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  4. Reach4

    Reach4 Well-Known Member

    Sep 25, 2013
    You could cap the stand pipe. If unused, its trap would run dry. I used a rubber stopper to close a standpipe that I was not using. [​IMG]
  5. Smooky

    Smooky In the Trades

    Apr 4, 2011
    North Carolina
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