Garbage disposal makes an occasional clunking noise

Symptoms

• Clunk happens once per rotation or only sometimes
• Not a constant grinding noise, just periodic thumps
• No visible object in the drain
• Noise has developed gradually

Likely causes

• CommonSmall debris lodged loosely in the grind chamberA small object that isn't fully wedged can knock around and only catch occasionally.
• PossibleWorn flywheel bearing causing slight wobbleA little play in the bearing can create a rhythmic clunk as it spins.
• PossibleLoose impeller swivel weight (on models that use them)Some disposals use swinging weights on the flywheel that can loosen.
• Less commonDisposal not seated evenly in its mountA slightly uneven mount can cause a periodic knock against the housing.

What to do

1. Turn off and unplug the disposal.
2. Shine a flashlight in and look closely for small debris that may not have fully jammed the unit.
3. Turn the flywheel through a full rotation with the hex wrench, feeling for a catch point that matches the clunk.
4. Remove any debris found with tongs.
5. Restore power and run briefly with water to see if the clunk is gone.
6. If the clunk remains at a consistent point in the rotation with no debris, the flywheel or bearing is likely the source.

Tools and parts

• 1/4-inch hex wrench
• Flashlight
• Tongs

When to call a pro

If the clunk is mechanical rather than debris, a plumber can confirm whether it's worth repairing or replacing the unit.

Safety