Feedwaters to a refinery are usually treated before being used in various processes. The type of treatment depends on the quality of the source water and its end use in the refinery. Turbidity, sediment, and hardness are examples of source water characteristics that may require treatment.

Water is the source of life and the continuation of life for living organisms, as well as a fundamental factor in the emergence of human communities and civilizations. Today, the total volume of the Earth's water, which is the source of life for all organisms, has remained almost constant and unchanging since its formation. These water resources were created about 4.5 billion years ago.