Now you're probably wondering, what do we need a whole other page for Water Flasks for? Well I'll tell you! Water Flasks can not only be purchased from a vendor but also made through Brewing, with a low trivial to boot! Now, not everyone will be able to easily make Water Flasks since the only way to make them is by using Pods of Water, which is a foraged item. However if you're too cheap to buy Water Flasks and have a ton of Pods of Water saved up, feel free to use your Brewing Skill and make some Water Flasks.
If you want to use your Brewing Skill to make Water Flasks collect the following items and visit your local Brewing Barrel. (Trivial 21)
Pod of Water x 4
Result: Water Flask
If you can't make the Water Flasks there is no real reason to worry since pretty much every general goods vendor in almost every town sells them and they're pretty cheap, roughly 2g a stack.