Drain cleaner may have caused leak
I recently had a leak in my bathroom drain under my slab foundation. I dug a hole under the house and replaced the drain assembly but there was another small hole in the pipe where the 2 inch cast iron pipe went onto a three inch pipe. I was able to JB weld that hole .The JB weld held fine and does not leak but the drain was draining slow so I put in some liquid fire to open up the drain(I have used it before with great results) and it seem to open up a leak farther up the drain pipe. I could see where there was water coming out of the dirt next to the pipe while the tub was running which tells me that its leaking farther up now and following the pipe to exit into the hole I dug. Here is the strange thing, I contacted a plumber that I have used before and he said it would be a week or so before he could get out to the house and since it was a drain leak(not a pressure line) and the leak was not very bad I decided to wait on him. Well, since then I have checked every day after we use the tub and now there is no leak showing up and the hole is dry as a bone. Any idea why it would leak one day and then stop? The only time it leaked was after I put the liquid fire in it and was flushing out the drain. Since then , nothing.