My proven method of winterizing the RV without antifreeze is turning the key and driving further south until the weather is warm enough without having to activate my winter package, tank heaters, light bulbs for the service bay, heaters for the coach, etc.
Works every time!
Do not rely on evaporation, use the proper amount of RV antifreeze in everything that water goes into or through. It is VERY expensive to repair broken pipes, fittings and tanks.
Dr4Film ----- Richard.