Dear Dr. Weragoda,
In my opinion, the solution suggested seems to be truly sustainable, both in terms in quantity and quality of potable water for rural households.
Some kind of treatment ensures the quality of the rainwater harvested for domestic use.
The harvested rainwater may not be sufficient alone in terms of quantity. However, augmenting it or using it for augmenting other sources of water could suffice the water needs in terms of quantity aspects.
Thank you.
With Kind Regards
Basavaraju Manu
