I bet its just the belt getting wet making noise. Doesn't mean the belt is bad. Most serpentine belts will get noisy when they get wet. The oem belt is high quality and modern serpentine belts do not wear out quickly like belts 30 years ago. Iirc in the manual the first inspect/replace of the belt if needed is 10 years 150k miles. Just make sure mud and gunk isn't getting on it and behind all the pulley's since that will cause added wear to bearings and such.