Water. More than 70 percent of our Earth is covered by it. You can live for weeks without food, but only a few days without water.

Water is so key to the existence of life NASA has looked for it on Mars to determine if our neighboring planet may have ever held life before.

And yet, as important as water is, so many people know so little about it. So here we present five fun facts about water that you probably didn’t know.

1. Most of the water on earth—97 percent, to be exact—is saltwater and can’t be used for drinking purposes. Only three percent is freshwater, and most of that is tied up in the polar ice caps and glaciers.
2. Water makes up about 60 to 70 percent of the human body.
3. Water is one of the few substances on Earth that occurs naturally in solid (ice), liquid (water) and gas (water vapor, steam) states.
4. We need to drink water frequently, but drinking too much water can kill you. Drinking too much water can cause a dangerously low dilution of electrolytes and other minerals in the body, leading to death by “hyper-hydration.” Fortunately, the two most common causes of this condition in healthy individuals can be avoided: long exercise periods where lots of water is consumed with few electrolytes ingested (try a sports drink instead); and water-drinking contests or hazing rituals.
5. Water is sometimes called the “universal solvent” because it can dissolve many substances, including metals (turning steel into rust, for example). In fact, pure H₂O is tasteless; many bottled and mineral waters obtain their unique tastes from the minerals dissolved in their source water.

The next time you turn on a tap or drink a bottle of eau, hopefully you'll remember these five fun facts about water and have a new appreciation for this vital liquid.