How long can a human go without water?
Rule of threes (survival)
You can survive three minutes of severe bleeding, without breathable air (unconsciousness generally occurs), or in icy water. You can survive three hours in a harsh environment (extreme heat or cold). You can survive three days without drinkable water. You can survive three weeks without edible food.
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.