[wildmanx]

That's not an answer to my question.

I meant, how sustainable is it to keep depending on foreign aid? Obviously dirty surface water that does not suffice for the whole population is not sustainable. But in the long run, creating new dependencies on aid can't be the solution. Any long-term plan that involves foreign aid is a bad plan.

[eurasiantiger]

Infrastructure is a lot more permanent than ad hoc solutions.

Not having the knowledge or equipment for drilling water wells is a problem. Getting the knowledge and the equipment there is another. The result is not a dependency—rather, the alleviation of a dependency.

[wildmanx]

Exactly! What we are discussing here is an ad-hoc solution. That $4 device will work for how long? A week? A month? Then we're up for the next one. A continuous stream of aid is necessary to keep this solution going. So, it's not sustainable, assuming we don't consider permanent aid a sustainable solution. (I don't.)

[eurasiantiger]

I agree, it is not a primary solution. However, in a world increasingly plagued by natural disasters, well water can often become unusable, and in those disaster scenarios devices like these can save lives.