Currently, 748 million people lack access to improved drinking water, and about 2.5 billion lack access to proper sanitation, putting them at risk of disease. For families around the world, waterborne illnesses mean lost income, malnourishment, or the death of a child.The direct linkage of clean water to health is very important, and is central to much of my own research. Indeed, in Accra, the capital city of Ghana, where my colleagues and I have been conducting research for more than a decade, the 2010 census showed that less than half of the city's residents have water piped into the house, and even that water is not guaranteed to be drinkable because of the leakage in pipes en route from the treatment plant (where the water does start out to be good) to homes. Thus, even among people with piped water in their house, one-third spend extra money to buy sachet water for drinking.
More broadly, though, we need water to grow food for the ever growing human population. Agriculture actually consumes most of the world's fresh water, and human-induced climate change (the Anthropocene), induced in part by the vast increase in agriculture, is shifting weather patterns and rainfall levels. Here in California we are in a severe drought, although the stories that we are about to run out of water are a bit exaggerated. Still, in San Diego County we import 90 percent of our water (mainly from the Colorado River), and a rain-fed lake near our house is more mud than water. The UN correctly links water to sustainability, and we need to be collectively very careful with this precious resource.