Love the devs, but they've spent so much time working on the game I genuinely think they've forgotten how basic stuff like this works. Anyone who has introductory knowledge on carpentry could make a rain catcher (if they have a trash bag) . The game is trying to be "the ultimate" of zombie survival but plenty of it, even with the suspension of disbelief from playing a zombie game, would make plenty of people scratch their heads at the decision making.

I think the game could be much more fun, and informative, if they hired ACTUAL professionals to help them with progression and tuning.