I don’t think I’ve ever covered 7 consecutive miles in Elk country and not crossed a stream, spring, or at least a little seep. But, I’ve never hunted the farthest south west states either.
I find I use about 4L every 24 hours. I also found that like others have said, freezing can be an issue. One trip I had to fill up midday only. In the early morning single digit temps, the creek water would freeze as soon as it was in a bag or bottle and not moving.
I also make it a habit to top off when I do come across a little stream every few hours.