Video · Plumbing Pipes, Faucets and Disposals
How Does a Garbage Disposal Work? Swapping One Under the Sink
How does a garbage disposal work? Not with blades. The motor spins a plate with two swiveling lugs that fling scraps against a toothed grind ring, and running water flushes the bits down the drain.
Job footageSwiftPro
- Topic
- Plumbing Pipes, Faucets and Disposals
- Length
- 0:30
- Posted
- October 5, 2026
- Shot by
- The SwiftPro crew, Northern Virginia
What you’re seeing in this video
Under a kitchen sink, a SwiftPro tech in a black hoodie, orange gloves and shoe covers unhooks the old disposal and sets it in a blue parts bin on a drop cloth. The new unit is still in its box on the floor beside the tools.
The text on screen walks through what happens when you flip the switch: the motor spins the grinding parts, food breaks into small particles, and water carries them into the drain.
What you can't see from above is the turntable at the bottom of the hopper, the round chamber under your sink opening. It spins fast, and centrifugal force does the rest.
Why it matters in your house
- Run cold water before, during and for a few seconds after. Cold keeps fats solid so they're chopped and carried off instead of coating the pipe.
- A hum with no grinding usually means the plate is jammed. Turn the power off, then use the hex key slot on the bottom of the unit to free it.
- Grease, stringy peels, coffee grounds and eggshells are the usual troublemakers. They rarely break the disposal. They clog the drain behind it.
Can a garbage disposal grind bones?
Small soft ones, like chicken or fish bones, usually go through a decent disposal, and the scraping even helps clean the grind ring. Big beef or pork bones don't. They just spin around and wear the motor. When in doubt, throw it in the trash. The disposal is for scraps that slip off plates, not the whole plate.
Want it done at your place? See Plumbing Pipes, Faucets and Disposals at SwiftPro or call (703) 997-9757.
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