A disposal is a blunt instrument by design — the noise of it doing its job is loud, and glass and bones make an alarming sound while breaking up. What matters is a noise that is new, that continues with nothing in the chamber, or that has changed in character. Three sounds cover almost all of them: a metallic rattle with something loose inside, a screech or whine from the motor end, and a drumming vibration that is the unit resonating rather than the unit failing.
Read this first
- Never put your hand inside the grinding chamber, powered or not. Use tongs or long pliers.
- Turn off the wall switch and unplug the disposal or switch off its breaker before reaching under the sink or into the chamber.
- A disposal that has been screeching may be hot. Let it cool before handling the body.
- Do not run the unit repeatedly to reproduce a metallic noise. Something hard rattling in the chamber damages the grind components a little more each time.
Step by step
Kill the power and look inside
Switch the disposal off at the wall, then unplug it under the sink or switch off its breaker. Fold the rubber splash baffle back or lift it out if it comes out, and shine a torch down into the chamber. A teaspoon, a bottle cap, a fruit stone, a piece of a broken glass, or a screw from something else entirely is the most common answer and it is visible in ten seconds. Remove it with tongs or long pliers — never with fingers, regardless of the power being off.
Turn the flywheel by hand
Insert a 1/4-inch Allen key into the hex socket in the centre of the disposal's base and work it back and forth. You are feeling for something hard catching at a particular point in the rotation, which will often push a trapped object up where you can see and reach it. The flywheel should end up turning freely through complete revolutions in both directions. Then look again into the chamber, because objects move when the flywheel does.
Check the impellers and the shredder ring
With the power off, look at the two swivelling lugs on the turntable — the impellers — and at the toothed ring around the chamber wall. Impellers should swing freely on their pivots; one that has snapped off or seized leaves the unit unbalanced and noisy, and it will also grind poorly. The shredder ring wears smooth over years and a worn one lets food rattle around rather than being cut. Neither part is serviceable on a domestic unit — this is information for the replace-or-live-with-it decision.
Separate a rattle from a vibration
Restore power and run the unit briefly with water. If the noise is a hard metallic rattle from inside, go back to the chamber. If it is a lower drumming or buzzing that you can feel through the sink, put a hand on the cabinet wall, the tailpiece and the drainpipe in turn to find where it is resonating. A disposal touching the cabinet back or side, or a discharge tube pressed against a pipe, turns normal motor vibration into a noise that fills the kitchen.
Check the mounting assembly and the sink flange
The unit hangs from a mounting ring under the sink flange, and that ring works loose over years of vibration. With the power off, twist the disposal body gently — it should be solid. If it moves or drops slightly, tighten the mounting ring in the direction the manufacturer specifies, usually by turning it with the lugs or with a screwdriver as a lever. Check the sink flange above is still bedded properly; a flange whose sealant has failed both leaks and rattles.
Check the discharge tube and the dishwasher hose
Look at the short elbow between the disposal and the trap and at the corrugated dishwasher hose if one is fitted. A discharge tube whose bolts have loosened will buzz against the housing, and a dishwasher hose that is touching the disposal body or the cabinet will slap and hum whenever the motor runs. Snug the discharge bolts evenly, and route the hose so it has a high loop and does not contact the disposal or the cabinet.
Interpret a screech or a rising whine
A screech, a metallic whine, or a sound that rises and falls with the motor rather than with the food usually means the motor bearings are going. Confirm it by running the unit with nothing in it and plenty of water: a bearing noise is present with an empty chamber, while a debris noise is not. A disposal is not a rebuildable appliance — the motor and the grind components are a sealed unit — so a bearing noise means planning a replacement rather than a repair.
Fit the missing bits that quiet a disposal
Two cheap items make a real difference. A splash baffle that has hardened, torn or gone missing lets far more noise out of the chamber and up into the room, and it is a $10 part that pushes into the flange. And on units that are drumming against a cabinet, a rubber anti-vibration mount kit or even a strip of dense foam between the body and the cabinet wall removes the resonance without touching the appliance. Both are worth trying before concluding a noisy unit is a failing one.
What this repair costs
Doing it yourself
$0–$40
Hiring a technician
$100–$300
Prices are general estimates for typical US jobs, not quotes. What you actually pay depends on your appliance's brand and age, the part required, your region, and each shop's labour rate. The DIY figure assumes you supply the labour and buy the part yourself.
Parts you may end up buying
| Part | Install | Typical price | Typical lifespan |
|---|---|---|---|
| Splash Guard | easy | $8–$28 | 5–10 years |
| Discharge Tube and Gasket | easy | $8–$30 | 5–12 years |
| Sink Mounting Assembly | moderate | $15–$50 | 10+ years |
| Jam Wrench | easy | $5–$15 | Tool, not a wear part |
| Batch-Feed Stopper | easy | $15–$55 | 5–12 years |
| Replacement Unit | moderate | $90–$380 | 8–15 years |
Still not fixed
When to call a pro
A disposal with worn impellers, a worn shredder ring or failing bearings is replaced rather than repaired — these are sealed units and nobody rebuilds them. A new disposal runs $90 to $380 for the unit and $100 to $300 installed, and a like-for-like swap on a plug-in unit is a reasonable DIY job if you can reuse the existing sink flange. Call a plumber if the mounting assembly or the sink flange needs to come out, if the sink is stainless and the flange is sealed in, or if you find the noise coincides with a leak. Call an electrician if the unit is hardwired and you find scorching or a burnt smell at the connection box.
More garbage disposal guides
- Garbage Disposal Jammed — Free the Flywheel Safely15–30 minutes
- Garbage Disposal Leaking — Find the Leak Point30–90 minutes
- Garbage Disposal Won't Turn On — No Hum, No Movement15–45 minutes
- Garbage Disposal Smells — Clean Out What Is Actually Rotting20–45 minutes
- Garbage Disposal Draining Slowly or Backing Up45–90 minutes