The cold water feed going to one of the sinks in the master bedroom sprung a small leak up in the attic. Water then ran along the beam until it came into contact with the wiring going down to a bathroom wall outlet. The water then ran down the outside of the wiring and on top of the junction box. Luckily the water never got into the junction box. Instead, it just soaked into the drywall.
I had to cut out the drywall to find out where the water was coming from. Until I did that, I didn’t know why the wall was wet. After I did that and pulled out the insulation, I was able to use a mirror and a flashlight to see where the water was coming from.
Whoever glued the 90 degree bend to the pipe running down into the wall must have been running low on PVC glue one day during construction and thought it was a good idea to cutback on glue where nobody would notice, like up in the attic under an air conditioning duct. Not that the duct was there at the time of the initial pipe installation. Having the duct there when the pipe was being installed would have made the installation job impossible, which coincidentally enough, also makes any proper repair also impossible. By proper, I mean cutting out the bad fitting and replacing it with a correctly glued one.
To fix the leak, I had to use special repair putty made by Loctite. They claim it can be used on wet surfaces. It seems to have done the trick. There’s no more water running down the electrical wiring. I want to go back up in the attic and put some toilet paper around the fitting to see if there’s any water still coming out. I don’t think there is, but I want to make sure.
I also need to repair the wall in the bathroom. I want to let it completely dry out first before putting the installation back in and replacing the missing drywall.
Update: That didn’t work. It turned out that whoever put the pipes together in the attic didn’t just skimp on the glue, they “forgot” to glue one of the joints entirely.