The Earth holds a huge amount of water, about one point three eight six billion cubic kilometres which is equal to roughly three hundred thirty three million cubic miles. Of that water, almost ninety seven and a half percent is salty ocean water and only two and a half percent is fresh water like rivers lakes and ice .

Out of all the fresh water on Earth only a very small amount is usable liquid fresh water on the surface It is estimated that only about zero point three percent of fresh water is liquid in rivers and lakes  . Most of the fresh water is locked in glaciers or deep underground where people cannot easily reach it.

If you want to imagine all Earths water in one ball it would measure about eight hundred sixty miles wide as NASA says It shows how much water is really there even though most of it we cannot drink or use directly.