Refrigerator Line Leak
The source of water is from a refrigerator line leak from the 1st floor. As the photos show, this is a basement space. This is evident through the actual encapsulation on the ceiling space, requires exposure or the opening of the wall/ceiling in order to determine and see where the exposed pipe is. As a result, all affected locations are removed and then replaced. This would require a fairly easy job to mitigate and repair, as usually a loss with a line like this is contained, however since it is a finished space, and it was discovered fairly quick, damages and flooring could be recovered.