Sustainability doesn't rely on good will. That is why I believe this idea would work.
"the majority of water illness-related deaths in developing countries occur in rural areas. Previous solutions haven’t worked since many people are unaware of the link between water quality and diarrhea. The group proposed creating an incentive-based system for local entrepreneurs to sell cheap and effective water treatment technologies. Such a system would work, they say, because it relies on profits instead of good will, and the burden of convincing residents of the treatment would fall on the local entrepreneur rather than a foreign aid worker."