Guatemala-based Ecofiltro sells water filters in the country and it is expanding. Ecofiltro is economically-sustainable and has a high social impact. It makes clean water affordable specially for consumers in rural areas, but also in cities. It uses a cross subsidy from high to low income costumers. It does not deliver filters for free. Its philosophy is that users should pay a price. All things considered Ecofiltro probably sells the best filter in the world.
The CEO, Philip Wilson, came to my class today :) His main message was: For a social enterprise to be successful it has to consider cultural factors which determine if users adopt or reject a product. Ecofiltro website is here. I will buy mine ASAP :)