Despite water being consistently cited as the top priority by poor communities and the fact that sanitation brings the greatest return on investment of any development intervention ($4 returned in increased productivity for every $1 spent), clean water, sanitation and hygiene education remain a low priority within the overall global development agenda. Health Every day, almost 900 children under-five die needlessly from diarrhoeal diseases caused by dirty water and poor sanitation. Diarrhoea is the second biggest killer of children under five years old worldwide. These deaths are entirely preventable; the simple act of hand washing with soap can cut the risk of diarrhea by 50%. Education Poor WASH provision severely hampers the educational prospects of the world's poorest communities. On average 272 million school days are lost each year due to water-related diseases. Schools without water and private sanitation facilities cannot attract teachers and girls often drop out as they reach puberty. In addition children, most usually girls, are frequently taken out of school to help find and carry clean water for the family. As a guide measurement it is estimated that 40 billion working hours are lost each year in Africa to time spent carrying water. Livelihood The massive cost of treating diarrhoeal disease drains national budgets – solving the WASH crisis frees budget for other development objectives. At any one time, half of the developing world’s hospital beds are occupied by patients suffering from water-related diseases. Individuals suffering from these diseases, or caring for sick children, are often unable to earn money yet face large medical expenses. Dignity With nowhere safe and clean to go to the toilet, people are exposed to disease, suffer a lack of privacy and dignity; problems which are particularly acute in overcrowded urban settlements. Those who are worst affected are usually from the most vulnerable and socially excluded groups who lack the power to call for their rights.