Almost 80 percent of the Earth's surface is covered with water. Here is how that 80 percent breaks down:
97% of all the water on Earth is salt water, which is filled with salt and other minerals and unfit for human consumption. To date there is no cost effective method to remove these minerals and make the water drinkable.
2% of all the water on earth is glacier ice at the north and south poles. This ice is fresh water and could be melted down, but it is too far away from civilization.
1% of the water on Earth is fresh water that we can actually use. We use this small amount of water for drinking, transportation, industry, heating and cooling, etc.