After things thawed out in Texas, I found that my kitchen sink will not drain. In checking the p-trap, I found the inside plumbing corroded and replaced all of it from sink drains (double sink) to stub-out. I have run a snake through the stub-out and down to what seems to be the right angle under the slab. I can not get past that, but there is nothing getting caught on the snake. I just can't get it to turn another corner.

I dug up outside, removing a concrete step for access. I have actually run a garden hose in about 10 feet downstream, and have another access hole 20 feet beyond, where I can see water running freely. I have tried putting boiling hot water in the sink and plunging. I sucked out a bit of grit and slime, but not much. I need an idea on how I can go upstream from the Y shaped access hole. Water left in the sink will drain overnight, with no sign that there is a leak. I.e., it must be seeping slowly through the pipe.

enter image description here

  • If you can block the vent, then use a garden hose in the stub, or push it in further, to flush water through fast enough you might dislodge whatever... But if that is corroded as well then it’s a risk...
    – Solar Mike
    Apr 4, 2021 at 18:51
  • Is the pipe in the slab cast iron drain pipe or is this plastic, i.e., PVC or ABS? Apr 4, 2021 at 19:58
  • The pipe is cast iron. I was going to cut a hole with a hacksaw, but that is going to take a long, long time. The old pipes that I left behind all seem very sound. There is nothing more that I can remove by unscrewing- the stub-out is there to stay. I had to break some of the fittings under the sink to get them off. 70 year old house. Apr 4, 2021 at 23:23
  • 2
    Stop before you cause unnecessary damage. Don't start sawing the cast iron drain pipes. If the cast iron pipe is sound, you don't want to damage it. A professional plumber can probably snake this. Apr 5, 2021 at 11:04
  • What size is the pipe at the 90?
    – isherwood
    Apr 5, 2021 at 13:23

1 Answer 1


I think at this point, you should call in a plumber with a snake & camera to determine the problem with the drain pipe. Instead of cutting, flushing and making a big mess a plumber with a camera on his snake could quickly determine the problem and the fix needed. If you call in a professional tell him/her the size and type of the piping you are dealing with.

my 2 cents

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.