How to troubleshoot causes of a loud noise in a garbage disposal

Is your garbage disposal making a racket even though you can’t see anything jammed inside? A garbage disposal is supposed to help make kitchen cleanup easier, not louder. If yours is making unusual or loud noises, something is likely off.  Let’s check out some common reasons behind the noise and how you can tackle them yourself.

Just a heads up: The tips we’re sharing might not match your exact appliance model. We aim to dish out helpful advice for all kinds of DIY appliance fixes, but different models can have their own quirks. For the best advice, it’s a smart move to peek at your manufacturer’s manual or give us a shout if you’ve got any questions.

Foreign objects in the disposal

One of the most common reasons for loud noises in a garbage disposal is a foreign object that doesn’t belong there. Whether it’s a utensil, a bottle cap, or a small tool, these items can accidentally fall into the disposal and cause clanging or grinding noises when the blades hit them.

What happens:

• The blades repeatedly strike the foreign object, creating loud metallic sounds.
• This can damage the blades or the item if it’s not removed promptly.

How to fix it:

1. Unplug the disposal or switch off the circuit breaker to ensure it can’t turn on while you’re working.
2. Shine a flashlight inside.
3. Look into the disposal to locate the object causing the noise.
4. Use tongs or pliers to carefully remove the item. Never use your hands, even if the power is off.
5. Restore power and run the disposal with cold water to check if the noise is gone.

Pro tip: Use a sink strainer to catch utensils or small items before they fall into the disposal.

Loose or misaligned parts

Over time, parts inside your garbage disposal can loosen or shift, causing rattling or vibrating noises. These components, like the mounting screws or flywheel, need to be securely fastened for the disposal to operate quietly and efficiently.

What happens:

• Loose screws or misaligned parts create a rattling sound when the disposal runs.
• Vibrations from these parts can amplify noise, making the problem more noticeable.

How to fix it:

1. Unplug the disposal or switch off the circuit breaker to ensure safety while inspecting.
2. Check the screws around the disposal’s mounting ring under the sink. Tighten any loose ones with a screwdriver.
3. Look inside the disposal for any parts that appear loose or out of place, like the flywheel or impellers.
4. Secure these components as needed.
5. Wiggle the entire unit to see if it’s firmly connected to the sink. Tighten the mounting ring if it feels loose.

Pro tip: Vibrations can loosen components over time, so periodic checks can help prevent noise issues from recurring.

Read more: How to fix a burning smell in your garbage disposal

Worn or damaged blades

The blades inside your garbage disposal work hard to grind up food waste, but over time, they can become dull, bent, or broken. When this happens, they might not spin properly or create uneven grinding, resulting in loud grinding or scraping noises.

What happens:

• Dull or bent blades can’t chop food evenly, causing the motor to strain.
• Uneven blade movement can result in scraping or clunking sounds as the blades spin.

How to fix it:

1. Unplug the disposal or flip the circuit breaker to ensure it won’t turn on accidentally.
2. Use a flashlight to look inside the disposal for visible signs of wear or damage on the blades.
3. Insert an Allen wrench into the hex socket at the bottom of the disposal.
4. Turn the wrench back and forth to check if the blades move freely. If there’s resistance, they may need cleaning or replacement.
5. If the blades are severely damaged or bent, refer to your disposal’s user manual for replacement instructions.
6. For older units, it may be more cost-effective to replace the entire disposal.

Pro tip: Avoid grinding hard items like bones or pits, which can wear out the blades faster.

Debris buildup inside the disposal

Over time, grease, food particles, and other debris can accumulate inside your garbage disposal. This buildup not only reduces efficiency but can also make the grinding process louder as the motor works harder to spin the blades.

What happens:

• Sticky debris causes resistance, making the blades grind unevenly and produce a louder noise.
• Buildup on the walls or blades can also trap odors, which might accompany the noise.

How to fix it:

1. Unplug the disposal or turn off the circuit breaker before cleaning.
2. Pour half a cup of baking soda into the disposal, followed by a cup of vinegar.
3. Let the fizzing action break down grease and grime for about 15 minutes.
4. After the fizzing stops, rinse the disposal with hot (not boiling) water to wash away loosened debris.
5. Add a handful of ice cubes to the disposal and run it with cold water.
6. This helps knock off any remaining buildup and can even sharpen the blades slightly.
7. If debris is still visible, use a brush or long-handled cleaning tool to scrub the inside of the disposal gently.

Pro tip: Regular cleaning every couple of weeks can prevent buildup from becoming an issue.

Read more: How to Clean a Garbage Disposal That Smells Bad

Faulty motor or bearings

If your garbage disposal makes a humming or grinding noise and doesn’t work as expected, the problem might lie with the motor or bearings. These components can wear out over time, especially with heavy use, leading to unusual sounds and reduced performance.

What happens:

• A humming noise indicates the motor is trying to run but is stuck due to a jam or failure in its internal components.
• Grinding or whining sounds might mean the bearings are worn or damaged, preventing the motor from spinning smoothly.

How to fix it:

1. Unplug the disposal or turn off the circuit breaker to avoid electrical hazards.
2. Remove the bottom panel of the disposal to access the motor wiring.
3. Check for loose or damaged wires that could affect the motor’s functionality. Tighten or replace them as needed.
4. Set the multimeter to the continuity or resistance (ohms) setting.
5. Place the probes on the motor terminals to check for continuity.
6. If there’s no continuity: The motor is likely faulty and needs replacing.
7. If the reading shows high resistance: The motor may be struggling, signaling wear.
8. If the motor or bearings are damaged, replacing them may not be cost-effective. Consider replacing the entire disposal for a longer-term solution.
9. Restore power and test the disposal with cold water to ensure it’s running smoothly.

Pro tip: If your disposal is older and frequently experiencing motor or bearing issues, upgrading to a newer model can improve efficiency and reduce noise.

How to maintain your disposal

• Use baking soda, vinegar, and ice cubes every few weeks to prevent buildup and keep the blades sharp.
• Add food scraps gradually to avoid strain on the motor and blades.
• Keep hard items like bones, fibrous foods like celery, and non-food items out of the disposal.
• Check for loose screws or signs of wear to address small issues before they become bigger problems.
• If the motor or bearings are failing or the disposal is old, replacing it might be more cost-effective than continuous repairs.

Read more: How To Install A Garbage Disposal

Thinking about a replacement?

If you’ve tried all this and the noise is still driving you up the wall, it might be time to shop for a new garbage disposal. The newer models are often more efficient and a lot quieter.

Find the right fit by checking out our guide on how to find your appliance’s model number.

Hope this helps you figure out what’s going on with your noisy garbage disposal. Remember, a little TLC goes a long way in keeping your appliances running smoothly and saving you some cash in the long run. For all your appliance parts needs and more DIY tricks, swing by AppliancePartsPros.com.

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If you’ve got any questions or need a hand, please reach out. We’re here to help keep your appliances in tip-top shape.