I carry 7 to 10 gallons in one gallon jugs; easy to store, easy to handle (8 lbs.), easy to fill. I have never had a problem filling 1 gallon jugs. I also carry a Katadyn backpacker water filter, 2 quart pot for boiling and iodine tablets for emergencies. Longest I have gone is eight days before I could refill my water jugs.
In conservation mode I use ~ 1 gallon/day: 1/2 gallon for drinking, 1 quart for dog, 1 quart for dishes, hygene. I shave with electric razor except on shower day, I use blade.
3 quarts for a shower (sun shower), usually twice a week. I usually have access to a lake or stream and will use that water for showering. Dog gets washed only if he gets muddy: ~1 gallon (again untreated water if available).
Laundry is done when I have access to municipal water (in 5 gallon bucket or laundromat).
-- Spiff