I gutted my downstairs bathroom to do some updating in there. The bathroom upstairs is directly above. I noticed that there is a leak in the sewer pipe that runs from the toilet into the main sewage pipe. The leak is a small hole in the horizontal pipe right before the elbow where it goes to vertical. The pipes are cast iron. Is there a way to fix this with putty or epoxy. If not is it possible for me to replace this myself with PVC or call a plumber. I can provide pictures if necessary.

Post the pictures. Check to insure that the leak is actually in the pipe and not in the joint above. No repair. If you have a leak in the pipe itself and repaired it, it wouldn't be long before you have another one some where else.

Post the pictures.

All right well I check it out and the leak was coming from the joint. I bought this putty that you work with your hands for 5 minutes and let it sit for 15 - 20 minutes around the joint. It worked... no more leaks... thanks for the quick response.

If this drain is in an area which will be closed off by walls when you remodel I would not trust that putty. Most home owners do not have the right tools to cut a cast pipe and replace it with PVC or cast. I'd call 3 plumbers for an estimate to replace and then make your decision.

Yeah... quick fix now will certainly work, but if you end up having to rip open the walls/ceiling and repaint, etc. down the road, this will be MUCH more expensive than it had to be, for sure! Since it is wide open underneath... fix it to 100% for future peace of mind!

Good luck!

Mark