I noticed some light lines on the dry wall of one my internally facing walls. Here is a picture of the water lines:
It's tough to tell from the picture (make sure to view in high resolution), but it is very light, and barely wet at all. This is unlike other water damage I've seen that is result of a broken pipe. I didn't even realize it was wet without touching it. It's also barely visible on the drywall in the next room that shares the wall. In this room, it is completely dry: