How long can a person survive without water?

The maximum amount of time an individual can go without water is a week. This time can be made shorter if the person is in difficult conditions, like heat. However, the week limit is a generous estimate, as three to four days is more typical.

People lose water when they sweat, go to the bathroom and exhale. Water helps the body form saliva, regulate body temperature, lubricates joints and helps deliver oxygen all over the body. If lost water is not replaced, the total amount of body fluid and blood volume may drop. Not enough blood circulating throughout the body causes blood pressure levels to fall dangerously low. Body temperatures also rise when the body is not sweating.