Clean drinking water is a basic human need. Unfortunately, more than one in six people still lack reliable access to this precious resource. The problem is particularly acute in the developing world.

This project examines the state of the world's water supply, and what can be done to improve it. It is divided into sections on sources, treatment and distribution of drinking water.

The sources section reveals where water is found on Earth and how such areas can be protected. The kinds of sources available also determine the types of management techniques that can be used to make the most of every drop.

In the treatment section, we examine the ways in which both humans and nature contaminate our water - and what can be done to clean it.

Finally, because most people do not live near their water source, the distribution section includes the many ways water can be moved or transported to those who use it every day.