I noticee on my dodge durango that of i let the car sit for a little bit white smoke comes out from.the exhaust any thing what it can be besides head gasket. It does not over heat or anything.
Your water? Do you mean your radiator? Then that means your mixing trans coolant with the coolant, not a good thing. Replace the radiator and drain and flush the transmission. If you are burning white smoke you also have a head gasket issue, time to tear down the motor. All of those things will cost you probably more than what the truck is worth.