While not conclusive, one of the main signs of water behind stucco is unexplained cracks. You may also notice chips and chunks of stucco breaking off. Missing caulking or caulk gapping and cracking around windows and doors is another indicator that you may have moisture buildup behind your stucco.  If your stucco still looks or feels damp several days after rain, or if you have spots that are always discolored, damp-looking, or soft, these issues strongly suggest moisture problems and need professional help. You may also find that the drywall inside your home, below windows, feels soft; this indicates moisture behind the stucco, damaging your home's walls from the outside-in.