Since the early 1990s, 1 billion people have gained access to clean water worldwide thanks to government initiatives and nongovernmental projects, but another billion are still in need. Dirty drinking water and poor sanitation facilities cause a host of health problems, including diarrhea, dehydration, cholera, malaria, and giardia, primarily in the world's less developed countries. These maladies are often fatal, but even when they're not, they usually keep the afflicted from working, parenting, studying, or otherwise participating in the activities that drive communities' prosperity.
Hundreds of thousands of people living in northeastern Brazil have gained a crucial source of easily accessible, clean water through the Million Cistern Project, a grassroots initiative that builds rainwater-gathering pools for local communities.