Urine is mostly water, and relatively sterile. But this does not mean it qualifies for the recommended 6 - 8 daily glasses of H2O, and here's why: in addition to the water content, urine contains trace elements of hundreds of other things —from undigested alcohol to nitrogen and potassium, and sodium, which makes it such a salty drink. (By the way, the first pee in the morning is more concentrated; and the more water you drink, the more diluted it will be.) Urine could — in rare cases — also have some toxic substances in it, such as lead or arsenic. It can also contain trace amounts of drugs that the urinating person has recently ingested, though probably not enough to actually give the sipper any high or show up on a drug test.