Streamwatch: What is fresh water?

Of all the water on Earth, only a very small amount is fresh water that can be used directly by people, animals and plants.

Water Molecule

Jane Cameron © Australian Museum

Water is the most common substance found on earth. It is essential for all forms of life and it can exist as a gas (water vapour and steam), a liquid (water) and a solid (ice). Water is made of tiny molecules, each so small that you can’t even see them with the most powerful microscope. These molecules are made up of three atoms: two hydrogen atoms and one oxygen atom. These atoms stick together due to electrical energy and, together, they are called H2O.

While water covers about 75% of the earth’s surface, only a very small amount is fresh water that can be used directly by people, animals and plants because:

  • 97% of this water is in oceans and is too salty for people, animals or plants to use
  • 2% is frozen at the north and south poles, in glaciers and on snowy mountain ranges.

A tiny 1% is fresh water but not all of it can be used. Some of this water is located under the ground, some is too polluted to use and some is simply difficult to transport and store.

Over 90% of the world’s supply of fresh water is locked up in ice in Antarctica.
 


Greg McDonald , Education Project Officer - Streamwatch
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