Garbage Disposal Making a Grinding Noise? Here's What It Means
A garbage disposal is never going to be silent, but there's a difference between normal operating noise and a sound that tells you something is wrong. If your disposal has started making a loud grinding, rattling, screeching, or clanking noise that it didn't used to make, something has changed inside the unit.
Here's how to figure out what's going on.
Something Is Stuck Inside
The most common cause of a sudden grinding or rattling noise is a foreign object caught in the grinding chamber. Silverware, bottle caps, small bones, broken glass, produce stickers, twist ties, and other items that slip past the splash guard can get wedged between the impellers and the grinding ring.
Turn the disposal off immediately. Never reach inside while the unit has power. Use a flashlight to look into the chamber from above and check for anything that doesn't belong. If you can see the object, use tongs or pliers to remove it. Never use your fingers.
After removing the object, press the reset button on the bottom of the unit and test it. If the noise is gone, you're good.
The Impellers Are Loose
Garbage disposals use impellers (sometimes called lugs) mounted on a spinning plate to push food against the grinding ring. Over time, these impellers can loosen. When they do, they rattle and clank against the inside of the chamber during operation. This is different from the sound of a foreign object. It tends to be a consistent metallic rattling rather than an intermittent clanking.
Loose impellers aren't something you can easily fix yourself. The disposal either needs to be serviced or, if the unit is older, replaced. Continuing to run a disposal with loose impellers will cause further damage to the grinding ring and the motor.
The Motor Bearings Are Failing
If the noise is more of a screeching or whining sound, the motor bearings may be going bad. This happens naturally over time as the disposal ages. Worn bearings create friction that produces a high-pitched sound, especially when the disposal is running under load.
Once the bearings start failing, it's a matter of time before the motor seizes. There's no practical repair for worn motor bearings in a residential garbage disposal. Replacement is the right move.
The Mounting Hardware Is Loose
Sometimes the noise isn't coming from inside the disposal at all. If the mounting ring or the connection to the sink flange has loosened, the entire unit can vibrate and rattle when it runs. This creates a metallic buzzing or vibrating sound that can be mistaken for an internal problem.
Check the mounting hardware under the sink. If the disposal feels loose or wobbly when you gently try to move it, the mounting ring may need to be tightened. This is a relatively simple fix.
When to Call a Professional
If you've checked for foreign objects and the noise persists, or if the sound is a screech or whine that suggests motor or bearing issues, it's time to get a professional opinion. Running a disposal that's making abnormal noises will only make the problem worse and could lead to a more costly failure.
Denver Disposal specializes in garbage disposal repair and replacement throughout the Denver metro area. Our pricing is on our site, there are no diagnostic fees, and same-day service is available. Book an appointment online or call (720) 312-3542.