From roaring oceans to trickling streams, water covers seventy percent of our planet! But did you know that less than one percent of Earth's water is usable by humans? Most water on Earth is salt water. It can't be used for drinking, bathing, or growing plants. We need freshwater. Yet about two-thirds of Earth's freshwater is frozen solid at the North and South Poles. And the water we can access--from lakes, rivers, streams, wetlands, or underground sources--is in danger of being polluted. There is not enough water to waste. We must join together in the quest to protect this valuable resource. With engaging text and eye-catching images--plus a special Going Green section--this book tells you all about Earth's water and what you can do to protect it.