Thanks for posting. It is the nut in the bottom picture. How in the world that thing has a crack in it when it has been tightened and untightened maybe 3-4 times ever is beyond me.
Just trying to figure out now how to fix this.
Looks like it is a little late. I tried loosening the nut just a little and now there is a big leak in the walls...went under in the crawl space to confirm. Evidently the nut was attached to that pipe and the pipe is now cracked.
So now I take it I need to cut away the wall, cut the pipe...
The nut directly below the shut off valve has a crack in it and water is streaming out. Since it is below the valve, I have to shut off the main water supply to get it to stop.
I have tried taking the nut off, but it seems as if it is welded onto a pipe. I can't see what is below the bolt...