I got this idea to make filling up jars at water sources more difficult (balance difficulty).
Why not add to the lore the fact that all water bodies have been infested with some kind of small "killer mosquito"?
Say, every time you get near a body of water, you get a constant DoT from something similar to the Desert Spitter, but causing damage AND some kind of illness. That would mean that, early game, if you want to fill up your water jars you'd have to get hurt plus possibly need antibiotics to cure that illness.
Basically, it means you'd have to trade having lots of water, with having much less medicine and risking an encounter while ill and injuried.