We just bought a 23 year old house that has had a lot of work done to it recently. There is a drop ceiling in the basement and I noticed recently that one of the tiles had a yellowing circle with a bit of black in the middle. I pulled the tile off and it is directly below a black PVC pipe that after process of elimination I determined was the drain pipe from the toilet on the second floor. The leak is very small and must be up higher than I can see because it is running down the pipe and took a little bit to actually produce water when the toilet was flushed. I am wondering if there is anything that I can do to determine where the actual leak is without ripping out drywall? Also what to do to fix this. Thank you for any help that can be provided.

Hi AHarvey421

Most likely what you have here is the toilet wax ring has failed at the upstairs toilet and is simply taking a long time to drip down the pipe and into the basement. I'm betting that under the toilet upstairs the leak is much greater but has yet to soak through the ceiling on the first floor is all (thicker/dense sheetrock/plaster ceiling).

To resolve the leak you need to install a new wax gasket. Pour a little 20% bleach solution around the flange and let some fall into the floor below to help kill off any mold that may try to develop... ;)

Good luck!

Mark