Depending how much water, how deep the puddle and how fast the car is traversing it, splashing water will work its way into the engine compartment, especially when there is no engine shield below to deflect the water. The right side is where the engine pulleys and belts are, and the water splashing on the belt and pulleys will cause some belt slippage and squealing until it dries out. Because the toothed timing belt is somewhat protected by its engine cover and will not slip, the squealing is from the serp belt.