Purify your own water
I just saw an article that might be of interest to someone living in rural Nicaragua (or in a US city where they put chlorine and fluorine in the water). The article is titled How to build a solar-powered still to purify drinking water. It appears in OffTheGridNews which probably has some other interesting articles.
The construction is pretty low-tech but I think it is a bit overbuilt. I am sure a Nicaraguan can come up with a cheaper implementation. The only critical components are a sheet of glass and silicon caulk.
For the water pans the builder uses Pyrex. I have seen a lot of relatively thin stainless steel ones (Las Segovias in Estelí typically has them) which would seem like a reasonable alternative.