We have a new(bought in April), 2014 Winnebago Sightseer 35G. I've begun getting a water drip from under the coach when hooked to city water. I use a regulator. Depending on how level the coach is, ...
Assuming you are under warranty still, I would let the dealer find the leak. Leaks can be tough to locate, as the water can travel quite a ways along the undercarriage of the trailer. If you do it yourself, I would start by the inlet and follow the hose. In any case, don't put it off. Good hunting!