Water, sanitation and hygiene have the potential to prevent at least 9.1% of the global disease burden and 6.3% of all deaths (Prüss-Üstün A., Bos, R., Gore, F. & Bartram, J. 2008).
An estimated 2.6 billion people lack access to improved sanitation, which is more than 35% of the world’s population (U.S. Census Bureau). Improved sanitation could save the lives of 1.5 million children per year who would otherwise succumb to diarrheal diseases. Worldwide, 884 million people do not have access to an improved water source (water that is supplied through a household connection, public standpipe; borehole well, protected dug well, protected spring, or rainwater collection). Regions with the lowest coverage of "improved" sanitation in 2006 were sub-Saharan Africa (31%), Southern Asia (33%) and Eastern Asia (65%). In 2006, 7 out of 10 people without access to improved sanitation were rural inhabitants (World Health Organization and UNICEF).
Unsafe drinking water, inadequate availability of water for hygiene and lack of access to sanitation together contribute to about 88% of deaths from diarrheal diseases, or more than 1.5 million of the 1.9 million children younger than 5 years of age who perish from diarrhoea each year, mostly in developing countries. This amounts to 18% of all the deaths of children under the age of five and means that more than 5,000 children are dying every day as a result of diarrheal diseases (UNICEF 2006).
Water and sanitation interventions are cost effective across all world regions. These interventions were demonstrated to produce economic benefits ranging from US$5 to US$46 per US$1 invested (Hutton G, L Haller, J Bartram 2007).
Improved water sources reduce diarrhoea morbidity by 21%; improved sanitation reduces diarrhoea morbidity by 37.5%; and the simple act of washing hands at critical times can reduce the number of diarrhoea cases by as much as 35%. Improvement of drinking-water quality, such as point-of-use disinfection, would lead to a 45% reduction of diarrhoea episodes (United Nations Millennium Project).
One in five girls of primary-school age are not in school, compared to one in six boys. One factor accounting for this difference is the lack of sanitation facilities for girls reaching puberty. Girls are also more likely to be responsible for collecting water for their family, making it difficult for them to attend school during school hours. The installation of toilets and latrines may enable school children, especially menstruating girls, to further their education by remaining in the school system (TheUnited Nations 2007, UNICEF and IRC).