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)

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

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

Just £15 can provide one person with access to safe water.
(WASHCost and WaterAid, 2014)

Lack of water, sanitation and hygiene costs Sub-Saharan African countries more in lost GDP than the entire continent gets in development aid.
(Using percentage estimate from UNDP: Human Development Report, 2006)