[DutchmenSport]

I fill mine until the overflow vent overflows. On mine, the fill port is in the wet bay in the front of the camper, the water tank is all the way to the back. On the side of the camper, in the rear, is a vent. It's not noticeable, but it's there. When the tank gets full, it spews over. Turn the water source off, and disconnect. It will stop spewing in a few seconds.

On mine, it's that brown bump out thing, that is just to the left and up of the red running light.