Half the hospital beds in developing countries are filled with people suffering from diseases caused by poor water, sanitation and hygiene.
(UNDP Human Development Report, 2006 http://hdr.undp.org/en/media/HDR06-complete.pdf  page 45)

Hygienic practices such as washing hands with soap can reduce the risk of diarrhoea by 50%
(Curtis and Cairncross, 2003; Luby, et al. 2005)

Hygiene promotion is the most cost effective health intervention according to the World Bank.
(Saving lives, WaterAid, 2012)

Around 315,000 children under-five die every day from diarrhoeal diseases caused by dirty water and poor sanitation. That's 900 children per day, or one child every two minutes.
(WHO/UNICEF 2014, 2015)

Diarrhoea is the third biggest killer of children under five years old in Sub-Saharan Africa.
(Child Health Epidemiology Reference Group (CHERG) 2012)

For every $1 invested in water and sanitation, an average of at least $4 is returned in increased productivity. (Hutton, Global costs and benefits of drinking-water supply and sanitation interventions to reach the MDG target and universal coverage, WHO, Geneva, 2012: page 4)