What really happens to wastewater on an aeroplane?

When passengers flush the toilet on an aeroplane, their wastewater is sucked into a sewage tank until the plane lands somewhere where it can empty its container.

Copyright: Dwayne Hards.

Airlines are not lawfully allowed to dump sewage during a flight, according to an article published by The Guardian. However, on the odd occasion, aeroplanes will leak small amounts of wastewater if their tanks are not looked after or maintained correctly, but this does not happen often and is extremely rare. There have only been a few recorded incidents where aeroplanes have accidentally dumped sewage during their flights.

When aeroplanes touch down on the ground, their wastewater tanks are emptied.

If an aeroplane's wastewater tank was full and the pilots wanted to dump some of the excessive sewage, they could not possibly do this because it's not possible as the only way to access the container is from the outside of the plane; therefor, pilots cannot possibly dump sewage during a flight unless they can somehow reach the outside of the plane.

Even if there was a leak in an aeroplane's sewage tank and wastewater did manage to escape from the plane, it would probably go unnoticed because the waste should evaporate miles before it gets anywhere near the ground. The only people likely to notice the leak are the staff emptying the plane's wastewater tank at the airport.