When i did ozy direct a couple of years ago we lugged all our water. I think we budgeted about 3 litres per day. We did it when it was mega hot....like 40 degrees at lower elevations, and we ran out of water and got quite dehydrated. Aiding gets much harder when you have no water. One idea if you're doing ozy direct would be to rap in and leave some water a couple of pitches from the top to save yourself carrying it all. We were lucky to find some (very stale) water at the bottom of the last pitch which was a god send.