Since water is quite heavy (8.3 lbs per gallon), even a 5-gallon can can be difficult for some. I'd suggest getting several different ways to carry water pre-determined and set up: Purpose-made water carriers, even clean 5-gallon buckets. A piece of wide webbing to carry two across the shoulders, even a yoke if you want. The important thing is to have clean water transport and to keep it - a secure lid in case of a stumble or whatever may be the difference between water and death.

And the maxim that people need a quart a day is just bare survival, on average. That assumes NO work is being done, no food is being digested, moderate temps. In reality a gallon or more is needed, every day.