I discovered a leak in the drain pipe from my kitchen sink (and dishwasher) as it joins with the main drain in my basement floor.

The leak is at a Y junction - the bottom of the Y is in the slab, one branch of the Y is terminated with a cap (I assume access for cleaning / plumbing problems?), and the other branch of the Y goes into the wall (and up to the kitchen). The bottom is in the floor, the top is capped off, and the branch goes into the wall. I don't know the exact angle or diameter.

I can see water bubbling from this 2nd branch (into the wall) when water is draining from the sink. After some cleanup, it look as though the ABS glue has either cracked, and there is no longer a proper seal - or it's been like this for the last 10 years since the house was built.

In any other plumbing fun, I've outright replaced the parts in question (eg, for the sump pump, I cut the pipe going out of the house, replaced it with removable parts, and put in a new pump, etc.). Doing so here is much harder because this part is in concrete.

What are the implications if I clean up the source of the leak really well (clean, sand, etc) and be liberal with some silicone glue? What's the correct way of repairing such an issue?


2 Answers 2


The correct way to fix this is to cut some of the pipe out coming from the Y, and replace it with glued-in fixtures. I don't think silicone would hold and it is certainly not up to code -- epoxy I would have no problem with myself but is also probably not code. Sand the plastic and make sure it is really clean if you go this route!

If you are inclined to re-glue, you can cut a section out of the pipe -- one cut right at the Y's hub, and another about a foot away. Then you need to remove the 3/4" that is in the hub, being careful not to damage the hub itself. This is a huge pain as you can imagine, and I usually use a rotary tool with an aggressive grinding bit to simply carve it out.

Your third option is to replace the Y which might not be as hard as you imagine, depending on the access you have -- just chisel out the concrete surrounding it enough to get a coupling on the pipe.

  • 4
    The third option is the right one. Concrete is not impossible to cut, chisel and repair, though lots of people start out thinking that way.
    – Ecnerwal
    Mar 17, 2014 at 14:44

Silicone should work but epoxy would work better.

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