Clay pot filter

Effective, totally no-civ-required water filtration!
Throw in some charcoal, to absorb chemicals, and you can probably drink from almost anywhere.

I’ve been wanting to fire one of these using coffee grinds to make it porous. Maybe I’ll have to use a fine espresso grind or something.

Could you use ground up charcoal from a fire pit to make it more porous? I would think that, with the purifying properties of charcoal, a charcoal/mud filter could even be more effective!

Thanks for the link, I have been trying to come up with good filters for a while now.