Every rural area would have had its traditional water management practices which includes traditional rainwater harvesting system. That will have to be understood and revived, rejuvenated to their past glory. These would form part of common sense solutions. I am not for recommending engineering solutions such as nanofiltration to the rural population.
In India, every part of it had its traditional water harvesting system, which were neglected during the 300 odd year British rule in India. I am sure this will be true of every other country in this world.
Engineering solutions are not as sustainable as common sense solutions.
Regards
Sekhar Raghavan, Director, Rain Centre, Chennai, India