Check out this TED talk by engineer Michael Pritchard, who invented a portable water filter that filters down to 15 nanometers. While the initial cost looks high (over $100), running costs are only .5c per day. The comments and discussion that follow the video are interesting.
Why gender matters – A tutorial for water managers
The authors of this manual point out that addressing gender improves the efficiency of water usage and of environmental sustainability. In fact, men and women have different views on things and different roles in relation to water use, so promoting their equal participation in decision making is [...]
L. A. Swatuk, A. Mengiste and K. Jembere, 200, Conflict Resolution and Negotiation Skills for Integrated Water Resources Management, Cap-Net UNDP.
The need for this manual, according to the authors in the overview, is that conflict is an unavoidable component of human interaction, and given the importance of water for survival it is inevitable that conflict [...]