I have a 70 year old house with a basement. There is a leak somewhere behind the wall of my kitchen sink. It only leaks when water goes down the drain, and then leaks below in my basement. There is no visible leak under the sink. Is there a hidden joint that could be leaking behind the sink in the wall?

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Originally Posted by tim4presme

I have a 70 year old house with a basement. There is a leak somewhere behind the wall of my kitchen sink. It only leaks when water goes down the drain, and then leaks below in my basement. There is no visible leak under the sink. Is there a hidden joint that could be leaking behind the sink in the wall?

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Been there! Done that in my own 55 year old home. There's a horizontal dain pipe in your wall behind the sink that runs to the kitchen stack that has either developed a leak at one of the joints oir simply ate through it. This isn't something a homeowner can do as it involves opening up the wall and replacing the pipe. Since my sink's on a outside wall I opted to take out the outside block wall behind the pipe instead of pulling the cabinets and opening up the inside wall. Once I rreplaced the bad pipe I patched and painted the wall and it looks as good as new. Good luck, Tom

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Originally Posted by speedball1

Been there! Done that in my own 55 year old home. There's a horizontal dain pipe in your wall behind the sink that runs to the kitchen stack that has either developed a leak at one of the joints oir simply ate through it. This isn't something a homeowner can do as it involves opening up the wall and replacing the pipe. Since my sink's on a outside wall I opted to take out the outside block wall behind the pipe instead of pulling the cabinets and opening up the inside wall. Once I rreplaced the bad pipe I patched and painted the wall and it looks as good as new. Good luck, Tom

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Thanks a ton, at least now I know what I'm in for

If your not to worried about what the inside of cabinet looks like, you could just cut a whole in cabinet and through wall and see if the leak is right behind where the pipe goes into the wall. Be careful when cutting the whole, so you don't hit your water lines(if they are in the wall) or electrical wires. I would suggest opening up a good area, you can always patch it back in. If you do this, and find the leak, let us know and we will help you fix the problem. Good luck.

I have seen it a few times and decided to drill a hole and run the drain through the base of the cabinet. Its just a thought .

Drains and waterlines in exterior walls can be a big pain for sure, Good Luck

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I have seen it a few times and decided to drill a hole and run the drain through the base of the cabinet

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We call that a "S" trap and they are outlawed in every code going. However, when faced with tearing up walls or tearing out cabinets it becomes a viable option. Good luck, Tom

If you do run a new drain through the base of cabinet, I would suggest using at least an aav(not a big fan of them, but better than no vent at all).