We have a 60 gal fresh, 40 gray & 40 black. When we dry camp we can run out of fresh water before the waste tanks fill up or the batteries discharge to 50%.
When water needs to be conserved, we will buy a case of 12 oz. water bottles for most of our consumption needs. We also have a 3 gal jug that has a spicket and set it outside. We fill about a dozen 1/2 gal plastic containers that we recycled from store bought juice containers. We use them for percolator coffee. And I have one 6 gal green jug from wal mart that I will add to the tank when the pump starts spittin.
And once we are close to running out of fresh water, it's time to dump the waste tanks, recharge the batteries, buy some groceries, and do some laundry.