According to the US Geological Survey 97% of all water on the Earth is found in the oceans. That is equal to about 317,000,000 cubic miles. Ocean water contains salt so the plants and animals on land cannot use it until the salt is removed. Energy from the sun causes water to evaporate. Once water absorbs enough energy it changes into water vapor. Although the water comes from the salty ocean, it becomes fresh through evaporation. The salt remains in the ocean.