I spent 6 months in the field in Antarctica in the late 60's. We had to melt snow or ice for all of our water. We burned nearly a pint of white gas a day including cooking. We used thermos bottles only for water that would be quickly drunk, not for storage. Water in a thermos will freeze, given time, and once frozen is a real problem to get out. We would just keep a lightweight stove handy and melt snow when we needed it.

The time spent on "water management' is just a part of cold weather camping and is time that needs to be spent.