Leak at base of main drain stack in basement

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by blgl, Mar 18, 2013.

  1. blgl

    blgl New Member

    Messages:
    2
    Location:
    Ohio
    There is a leak occurring somewhere right near ground level in the main drain stack shown in the picture. The leak comes up from between the outside of the ABS 4" drain and the concrete floor, near the back of the drain (closest to the wall and underneath the 3" house drain pipe). There is no water on the outside of the drain, so the water is coming up from the concrete. When I leave a sink running, I can see the pool of water start to form at the back of the drain pipe, but then when I turn off the faucet and clean up the water, it will still continue to give a smaller amount of water overnight, even without use of anything attached to that drain.

    IMAG0086small.jpg

    I plugged up the drain pipe to hold water in it, and the leak seems to continue to occur when the water level is right at or just below floor level. Right at the concrete floor, the plastic drain bevels out to a slightly larger diameter. Inside the drain, I can see a gap all the way around the pipe that corresponds to that area, so it looks like there is some kind of a ring that they have manufactured into the drain. I think the leak is occurring somewhere in or at the edge of that ring. You can see the gap in the picture that shows the inside of the drain, and it is right below the opening of the 3" house drain.

    IMAG0088small.jpg

    What purpose does that gap provide?

    I've tried to look in there with a mirror, but can't see very well, so I can't find the exact leak. I don't know if there is a good cleaner which would clean up that area without damaging the ABS, so that maybe I could see better?

    Can that gap just be filled in with an epoxy or putty. Or does it allow for expansion or exist for some other purpose so that it can't be filled in to be flush with the rest of the inside of the pipe? If I could just fill in that gap, I think that would probably solve the problem.

    If it can't be patched from the inside, would I need to chisel around the concrete to apply some kind of patch on the outside?
  2. cwhyu2

    cwhyu2 Consultant

    Messages:
    1,347
    Location:
    Cincinnati OH
    Looks like they put the ABS into the hub of clay pipe.
  3. blgl

    blgl New Member

    Messages:
    2
    Location:
    Ohio
    The house is about 25 years old, so I assumed the whole drain was ABS, but I don't know for sure. The cement floor was painted and some of that paint is on the part of the pipe that flares out around in a ring. Some of the paint on the floor around the pipe has flaked off because of the water laying on it.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,811
    Location:
    Cave Creek, Arizona
    You can't tell anything about the outside joint by looking inside the pipe. IF it were connected to a clay pipe the fitting at the bottom would be a "red" color and your photo does not indicate that. Besides, ANY "defect" in a vertical pipe would NOT leak unless the water backed up above that point in the pipe. The "gap" should just be the space between the end of the pipe and the "bottom" of the fitting's hub.
  5. cwhyu2

    cwhyu2 Consultant

    Messages:
    1,347
    Location:
    Cincinnati OH
    I stand corrected, might be ground water?
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,129
    Location:
    New England
    If you cut the end of the pipe square, and insert it fully, there's usually little to no gap between the end of the pipe and the bottom of the hub in the fitting, providing proper overlap and minimum friction, strength, and sealing.
  7. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,249
    Location:
    Land of Cheese
    One thing is for sure, which is that if the pipe or fitting is leaking, it's going to have to be removed to fix it.
    With only the information we have, a positive diagnosis is not likely.
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