We often call the earth the Blue Planet. That's because almost three quarters of the earth is covered with water. People think we are not short of water. In fact, it is wrong. Most of the water is salt water in the world's oceans. Only about 3% is fresh water that we can drink.
You may think that most of the fresh water is found in the lakes and rivers, in fact, less than 1% of the fresh water can be found in these places. Around 70% of the earth's fresh water is ice in the polar（极地的） places, they are too far from the places where most people live. It's difficult for people to get it.
The second﹣greatest source of fresh water on the earth is under the ground. This type of water is called ground water. Places that don't have fresh water from rivers and lakes depend on groundwater for drinking and other uses. Groundwater also can't get away from pollution. Chemicals（化学制品） used in farming and factories can get into the ground.
The earth has little usable water. Luckily, each of us can do something to save water. Kids and adults are saving water wisely in their own communities. If we work together, we will have a better world.
