Water is an essential resource for survival, and is as important in the Lost in Blue franchise as it is in real life.
Characters have a hydration stat that must remain above 30% or they will start to have problems. Reaching 0%, they won't directly die, but the characters won't be able to eat anything and their HPs will slowly decrease. Water can be drunk and filled from various sources such as rivers or at springs, and can be stored in glass bottles or in large amounts in Oil Drums.
(This section will eventually include a list of all locations in every game where water can be gathered from.)
Water can usually be found near the starting camp in each game, along the bank of a river in an easy-to-locate place.
Water, in addition to being essential to keeping your characters alive, is used to keep domesticated animals alive. To water an animal, interact with it while you have a bottle of water in your inventory. You should be prompted with a question if you want to give the animal water.
Water is also used in cooking, especially when making Soup.