The physical supply and use tables (SUT)  for water resources describe the flows of water to and from the environment and the economy. It covers three types of flows:
1. Abstraction of water from the environment into the economy;
2. Flows within the economy;  and
3. Return flows from the economy back to the environment.

The use table focuses on who uses or receives the water. The economic unit that performed the water withdrawal from the environment is the user and the abstracted water is either consumed by the same unit or is distributed to be used by other economic units. Once water is no longer needed by the user, it is released back and recorded as used by the environment.