Water quality is a beast -- it's hard to measure and control what may harm us in water.
We do know that many people do not have access to drinkable water. One way to improve their water is to give them cleaner supplies and/or purification technology. Tedd Miguel (UC Berkeley economist) reports that people in a study community in Kenya are unwilling to pay more than 15 cents/month to have clean water. [The community is considered to be typical of the developing world.] That's a problem: About 20 percent of kids in the study community have diarrhea in any given week.
Why do people who can afford such an amount fail to buy higher quality? The authors suppose that people may lack the practical health knowledge to understand the importance of clean water.
One organization trying to address that issue is the San Francisco-based Aquaya Institute, which "delivers scientific and technical innovation for preventing waterborne disease to developing countries." They'll need help.
Bottom Line: Bad water kills many people in developing countries. More wells and pipes will not solve the problem without better institutions for managing water quality.
hattip to JC