I have a 2011 Cadillac SRX that the power steering will fail occasionally when driving thru standing water. Purchased in 2012. Has always done this. Figured it was typical of this design.
Time to replace the serpentine belt(s). When you do, have all pulleys inspected especially including the tensioner pulley. I would assume that you keep your power steering fluid levels correct. This should solve the problem.
Also check to see if any splash shields are missing. And make sure the timing belt tensioner can move if you live in the rust belt.