Thank you for the reply. I am not trying to argue myself into being right, but I have some addition information and questions that I think might be relevant.

If other pipes tie into the broken pipe inside the slab then I see that the water would have other places through which to pass and my problem is not solved. But if this happens to be a lone single pipe that passes through the slab, then isn't this essentially a pipe that passes through one long "hole" in the cement such that if the two ends of that cement hole were plugged (with the liquid rubber) then the water would not have any other opening through which to escape except through the pipe itself? Admittedly, I do not know if other pipes tie into this one in the slab.

Also, I should mention that the water leaks from where the pipe enters the slab (the higher elevation side) but does not leak from where the pipe exits the slab (the lower elevation slide).

The idea for using liquid rubber came to me because the leak resolved itself at one point for about 1 year and just recently restarted (no water and no smell for that 1 year period). I surmised that the space between the pipe and the cement must have become gunked up from the kitchen waste water and sealed itself during a several month period when much less water was being used in the kitchen. I thought that if it naturally sealed itself up once then I could fix it by artificially sealing it up myself with something more durable.

Acknowledging that the liquid rubber approach might not solve the problem, do you think that attempting it could cause more harm in the long run?

Thanks again for any thoughts.