Fresh water can come from a variety of different sources on Earth. While a great majority of the Earth's water comes from the oceans that cover almost 70 percent of the Earth's surface and is too salty to drink, there are still many places from which fresh water is naturally produced.
One important source of fresh water that is often overlooked is rainwater. Rainwater is the product of water from the Earth that has been evaporated into the Earth's atmosphere and is turned into rain. During that process, the water becomes fresh water and is cultivated in many places throughout the world to be used as a suitable supply of drinking water and water to feed crops. Harvesting rainwater is a technology that has been used by ancient civilizations and is one that is still widely used in many rural areas to make the most out of an endless supply of fresh water that is often taken for granted.
Underneath the surface of the Earth lies a very large source of fresh water. Groundwater is the largest source of fresh water on the planet, and the second largest source of water, next to the water found in the oceans. Like the salty sea water, much of it is also not able to be consumed by people or animals. However, a percentage of groundwater is fresh and can be desalinated and refined in order to provide suitable drinking water for populations.
A major topic of debate surrounding the Earth's climate change problems is the melting of polar ice caps and the reduction of ice shelves all over the Arctic. Along with groundwater, ice makes up the second largest fresh water source on the planet, accounting for a little less than two percent of the Earth's water. Some of the fresh water preserved in ice, particularly the ice caps of Antarctica, is thousands of years old. Much as with groundwater and ocean water, it is difficult to use ice water as a source of consumable drinking water, but it is possible.
Rivers, lakes, streams and natural springs are considered to be surface water sources and compose the final fraction of a percent of the fresh water on Earth (0.0014 percent). Although there are millions of fresh water lakes and many miles of rivers and streams on the planet, these water sources account for an almost negligible amount of fresh water. They are still vitally important, however: A lot of our consumable drinking water is taken from natural springs and fresh water rivers and streams. Surface water continues to be one of our most important source of fresh water on the planet.