Depends on duration of walk or camp. I tend to dry camp which means I bring my own water. If it's just a walk, one liter which weighs about two pounds. Overnight is at least three liters which is about six pounds. Obviously I can cut my weight simply by relying on trail water sources but then I would have to treat the water. I could do that chemically or with a filter. Or pre-filter with a coffee filter then boil the water using the stove and pot so as to not have the weight of a filter or worry about breaking the bottle with the chem treatment. A trick I've learned to reduce water weight is to drink lots of water prior to your trek so you theoretically won't need to carry any water but, being a prepper, I tend to want to bring along water anyhow. Long-winded, ain't I?
