How is the lavatory/galley water storage tank pressurized?

The lavatory/galley water storage tank is pressurized primarily by bleed air fed through a pressure regulator. This method is efficient for maintaining the required pressure in the tank, allowing the water to flow properly to the lavatory and galley systems when needed.

Bleed air, which is taken from the aircraft's engines, provides a reliable source of pressurization without needing separate electric pumps or complex hydraulic systems. The pressure regulator ensures that the air is delivered at the correct pressure, preventing water from leaking or being delivered at an improper flow rate. This method is particularly advantageous in aviation due to its simplicity and integration with existing aircraft systems, allowing for efficient operation while conserving power and weight.

The other methods mentioned, such as electric pumps or hydraulic systems, are used in other aircraft applications but are not typical for the specific need of pressurizing the lavatory/galley water storage tank. Manual pumping would be impractical and inefficient in a modern aircraft design where automation and reliability are critical.