Over 660 million people lack access to safe water and 2.4 billion people lack access to sanitation facilities. A third of the global population lives without access to a toilet and more people have mobile phones than toilets. A review of rural water projects in Africa, South Asia, and Central America found average failure rates of 20-40%. Globally, a third of schools and healthcare facilities in low and middle-income countries lack safe water and adequate sanitation. The water crisis poses the largest risk to society according to the World Economic Forum.