Shortly after the plane crash, Olive tells Johnathan ‘John’ Stone: “I have a refillable bottle that self-filters. I can drink from any water source.”
These self-filter water bottles can be life savers if lost or stranded in the wilderness where water quality is questionable. Because I hike, camp and boat far from civilization, I bought one of these water bottles a few years ago. I don’t use it as my water bottle; it’s there in case of emergency, when the only drinking water available is from the ground.
Olive explains how to use the water bottle a few chapters in after Johnathan asks her to refill his regular plastic water bottle.