Indeed.
I'm not thinking only of the economics. Proof of concept, environmental, and economic.
Would make it near necessity I'd have thought.
I did stay at a friend's for a while - cottage high on a hill, no mains. We drank bottled water, and washing/toilets etc was seen to by water collected from an apparently constant 'wash' from further up the hill - not quite a stream. I think it was stored in an outside tank and fed using gravity. That was treated with UV - an inline sort of light shining arrangement.
He drank that water, despite tests suggesting that he shouldn't. Haven't seen him for a while - hope he's OK ;-)