Here are some facts about global water scarcity, according to the World Health Organization.
* Water scarcity affects one in three people on every continent and is getting worse as water needs rise with population growth, urbanization and increased usage by households and industry.
* Almost one-fifth of the world's population (about 1.2 billion people) lives in areas where water is scarce. One quarter of the population lives in developing countries that face water shortages due to lack of infrastructure.
* Poor water quality can increase the risk of cholera, typhoid fever, dysentery and other infections.  Water scarcity can lead to typhus, plague and trachoma, an eye infection that can cause blindness.
Water scarcity encourages people to store water in their homes, which increases the risk of contamination and provides breeding grounds for mosquitoes, which carry dengue fever, malaria and other diseases.
A lack of water has increased the use of wastewater for farming. More than 10 percent of the world's people consume foods irrigated by wastewater that may contain chemicals or disease-causing organisms.