When you go into dry camp, you need enough water for that day, and the next morning to get to the next source. The best way to handle this is to cook dinner for lunch, and eat lunch for dinner. There is no need for any "crew water". Have every person carry enough so that they will have 2L in the morning, and you will have plenty generally. It does depend on distance between sources. 4L per person will often suffice. If you want to cook and wash pots etc, then carry more and then each person contributes some to the cause. We required each person to have 6L capacity and that was plenty. We had 3 dry camps. Most just carried 6 1L smart water bottles. Some had 4 and a 2L platy. One had all 2L platys because he lost every water bottle he had, kept leaving them places and had to buy $45 worth of platys at a food pickup.
The one thing I would caution against, is boys will get to some camps, like tooth ridge for instance with interesting rock formations they can play in, and then go running around and playing the rest of the afternoon, getting hot and sweaty, forgetting that their water supplies are not limitless.
I wouldnt carry any large crew water containers ever. Simply not needed, and it encourages poor water management on the boys parts, they assume there will be a limitless supply for them.
At one camp, the water board had no information. We found water 3/4 mile away up a dry creekbed. Took a couple hrs to get water. At another the water board said "trickle" , it was BONE DRY, not water at all. Lesson, DONT trust the waterboard, unless it says ample, carry water like there may not be any, because there may not be.