The Potable Water Tank Module is filled during ground-service and stores the water during the entire flight for the corresponding supply to the consumers. A level measurement system is included. Based on the requirements for the installation envelope the tanks may be round vessels for structural weight optimization or have fuselage-conform shapes.
Depending on the selected system architecture the tank may be pressurized or have ambient pressure. For a weight-optimized design carbon fiber composite is used in most cases.