Survival skills
A human being can survive an average of three to five days without the intake of water. The issues presented by the need for water dictate that unnecessary water loss by perspiration be avoided in survival situations. The need for water increases with exercise.
UN-Water
The physical world of water is closely bound up with the socio-political world, with water often a key factor in managing risks such as famine, migration, epidemics, inequalities and political instability. Since 1900, more than 11 million people have died as a consequence of drought and more than 2 billion have been affected by drought, more than any other physical hazard.