Though not as refreshing as a glass of ice water, human urine is potable and contains around 95 percent water, so it can help hydrate a person caught in an extreme situation. However, about 5 percent of urine has waste products from the kidney - vitamins and minerals such as calcium and potassium. After a couple of days of drinking nothing but the same recycled urine, there will be more waste and less water in the fluid, making consumption risky.
Drinking concentrated urine that has been filtered through the body multiple times will result in a liquid that, when consumed, can actually trigger kidney failure. Putting recycled urine through the body more than once raises the risk of triggering renal failure, which can be just as deadly as dehydration.
In terms of survival, consuming nothing but urine is only a temporary solution that will not work over extended periods. Overall, drinking urine should be treated as an absolute last resort as a survival technique, and those who have suffered from certain stressors, such as crushing injuries, can actually do more harm than good by consuming their own urine.