Aircraft Water Tanks and The Water and Waste System

When an aircraft is transporting individuals over long distances, it is important that passengers have access to facilities such as lavatories and aircraft galleys for the means of providing a comfortable experience for all. In order for passengers and crew members to take advantage of the restrooms, coffee and tea makers, sinks, and other facilities and equipment of an aircraft, water must be managed and supplied to each. In this blog, we will discuss the water and waste system of aircraft, allowing you to better understand how potable water is supplied to facilities and how wastewater is removed and stored during a flight operation.

In order to store water for use during flight, aircraft water tanks are commonly implemented within the fuselage. While stationed on the ground between operations, a water truck will pump potable water to fill the tanks as necessary with the use of the fill valve. To ensure that a proper amount of water is supplied, aircraft water tank sensors will relay measurements to the flight crew. On a typical passenger airliner such as the A320, the tank may feature a capacity of up to 200 liters of water. In order to prevent an overflow of fluids in the tank, an overfill drain line or drain outlet is provided.

To efficiently transport water to the various facilities that require it, electric pumps are used to pressurize fluids so that a positive rate of flow is achieved. Piping serves as the medium for water to move through when being transferred through the aircraft, and heat trace wiring may be implemented for the means of preventing fluids from freezing when flying in colder conditions. While transporting water to various areas is important for its use, its removal is also just as crucial. For the toilet bowls of lavatories, differential pressure generated by a vacuum generator serves to remove the waste water from the bowl, directing it towards a waste storage tank. Waste water from lavatories is typically kept in a tank reaching upwards of 170 liters, and such waste is retained until the aircraft lands so that it can be safely removed.

With the use of water heater equipment, sink water from lavatories and aircraft galleys can be heated up as necessary. As the waste water from such sources is removed from sinks or basins, it will eventually be discarded from the aircraft with the use of a drain valve and heated drain masts. To ensure that aircraft pressurization is not rapidly lost when discarding waste water, air stop valves are implemented so that an opening is only made whenever a threshold of water is met.

Once the aircraft is on the ground and is being serviced, a lavatory service cart is used to drain waste from the aircraft waste system tank. To drain the tank, the waste drain valve is pulled and the drain plug is removed. As waste water may contain various pathogens or bacteria, ground support equipment will also be used to pump cleaning solutions into the waste tank for safety and cleanliness.