> Clean water is often considered a rare commodity in this scenario.
>
Good Idea, but wouldn't it feel like the water should give health instead ?
Water giving health makes sense.
You should probably add some more story behind the character. If it is a wasteland out there why would you be just wandering about if it so dangerous? You would find a dwelling then only go out to scavenge for food, water, and whatever other supplies.
This isn't great but just an example off the top of my head:
There is a disease caused by the nuclear fallout that is plaguing mankind and this scientist thinks he found the cure but needs to collect samples (of something) to create the vaccine.
It's hard to think of the best way to 'keep score' in a post apocalyptic world as the only goal is usually survival . . .