Where does airplane toilet waste go?

Waste from an airplane toilet goes into a sealed holding tank, usually at the rear of the aircraft's belly. When you flush, a vacuum system sucks the contents through pipes into the tank. After landing, a lavatory service truck connects to a panel on the outside of the plane, drains the tank, and takes the waste to a disposal point at the airport, from where it is treated like other sewage.

How the vacuum toilet works

Modern airliners use vacuum toilets. Pressing the flush button opens a valve, and the pressure difference between the cabin and the outside air (or a vacuum pump on the ground and at low altitude) pulls everything into the tank with a small amount of blue disinfectant liquid. That's why the flush is so loud and fast, and why it uses very little water.

Is waste dumped from planes?

No. Airliners have no way to empty the toilet tanks in flight. Rare stories of "blue ice" falling from the sky come from leaks: liquid from a faulty valve freezes on the outside of the fuselage and can break off — not from intentional dumping.

Sink water

Water from the lavatory sinks (gray water) is usually drained overboard through heated drain masts, where it disperses into fine mist at altitude. It isn't sent to the toilet tank on most aircraft.

FAQ

Do airplanes dump toilet waste in flight?

No, not in flight and not before landing. The tanks are only emptied on the ground by service vehicles.

Where are the toilet storage tanks on a plane?

In the lower fuselage, usually toward the rear, below the cabin floor; larger aircraft can have several tanks.

Why is the airplane toilet so loud?

Because it uses vacuum suction instead of water to move waste quickly into the tank.

What happens to the waste after the plane is serviced?

It goes to the airport's waste disposal facility and into the sewage treatment system.

Why shouldn't you flush things other than toilet paper?

Objects can clog the vacuum system and put the lavatory out of service for the rest of the flight.