Water leak by the hot water tank

So I have to say I'm a bit disappointed. While draining and flushing the lines after being winterized, finding that the hose to the shower head leaks and pops off, I also have noticed that there seems to be a small leak somewhere by the hot water tank.  I need to test and see if it is coming from the water tank, the pump (the pump is in the same area) or if it is from the fresh water tank fill spot.  It was small enough that I didn't notice it at first.  It doesn't leak when water is not being pumped through the coach. I let it sit for a day and its dry so it doesn't seem to leak until water is run or being filled.  So next is try to determine where the leak is coming from, then its going back to the dealership for repair. If anyone has had the same issue were you able to fix it yourself or did it need repair by the dealer?