Sure works.

Now, how to get people to actually believe that the water is dirty, and that bacteria do exist...

Sorry mate, as simple as it is, this thing won't work. Not for the people it's supposed to help.

And if you don't believe me, just ask yourself if villagers who go and fetch water at the same exact spot where a big croc ate someone the day before would be bothered by things they can't see, like bacteria...!