Is your garbage disposal making a loud grinding noise, and you don’t know where it’s coming from? There could be several factors at play, such as hidden debris or loose parts. Identifying and resolving the exact cause is crucial to ensuring a lasting solution. Here’s a close look at the top causes of grinding noises and how to fix them.
Foreign Objects in the Disposal
Even though disposals do a good job at grinding food waste, it’s easy for foreign objects to get stuck in them. Maybe a spoon accidentally slid into the drain without you noticing. Or perhaps someone placed fruit pits in the disposal, thinking it would chop them into tiny pieces.
When these items get trapped, they scrape against the shredder ring or flywheel. As they rattle around, they create a loud grinding noise that resembles metal-on-metal or rocks tumbling. The only way to fix this problem is to take out the foreign object. A plumber can remove it for you if you are unable to reach it safely.
Worn or Damaged Grinding Components
The garbage disposal has several grinding components, like metal teeth, impellers, and a shredder ring. The more you use the disposal, the more wear these parts endure. When they become dull, bent, or cracked, you might notice a grinding noise that gets louder with each use.
If the shredder ring completely breaks, the disposal won’t break down food scraps, potentially causing clogs. To repair the damage, one of our plumbers will replace the worn parts.
Clogged or Jammed Blades
Just because the disposal makes a grinding noise doesn’t necessarily mean it’s damaged. When the blades are jammed, they can’t spin freely, which can sound like clattering or scraping.
Fibrous foods, such as celery or onion skins, can wrap around the impeller, causing tangles that lead to this problem. One of our plumbers can clear the jam and make sure none of the internal parts are damaged.
Loose Mounting Parts
The mounting hardware on the disposal must be secure and tight at all times. This keeps it securely connected to the underside of the sink, preventing it from shifting or dropping. When the mounting parts become loose, the disposal will vibrate, shake, and make a grinding sound.
Homes that rely heavily on the unit tend to experience more issues with loose mounting hardware. Simply tightening the brackets might fix the problem, or you may need a whole new mount.
Improper Food Types
A garbage disposal can tackle a lot of different scraps, but there are several foods you shouldn’t put in it. Bones and coffee grounds both grind harshly against the impellers, leading to damage. These items don’t break down very well either, meaning they stay in the drain, sometimes causing clogs.
Here are some of the many different foods you should never put in a garbage disposal:
- Bones and hard meat scraps
- Coffee grounds and fine grit
- Fibrous vegetables like celery
- Grease, fat, or cooking oil
- Eggshells and broken shell pieces
- Starchy foods such as pasta
- Fruit pits and large seeds
- Rice or oatmeal clumps
Motor or Bearing Problems
Does the disposal continue to make a grinding noise even when it’s empty? If so, there’s a good chance something is wrong with the motor or bearings.
The bearings are responsible for keeping the moving parts aligned. When they wear out, the components will rub against each other, producing a grinding or screeching noise. We can replace the bearings to restore proper function.
Several symptoms point to motor issues, including slow performance and overheating. For most units, motor problems indicate the need for a replacement of the whole disposal.
Improper Installation
Poorly installed garbage disposals are much more likely to experience problems. Mistakes, like loose mounting or improper tightening, can cause vibration and loud noises. Alternatively, the installer may have failed to connect the wiring correctly, causing the motor to short out, which can also produce harsh sounds.
Hiring a skilled plumber for the installation is the best way to ensure optimal performance. We’ll align and secure everything, so the unit performs reliably from day one.
Rust or Corrosion
A garbage disposal is in one of the dampest environments in the whole home—the kitchen sink. All of the moisture they come into contact with rusts the external and internal parts over time. Corrosion inside the grinding chamber creates rough surfaces. As food scraps pass through, you might hear a scraping or grinding noise.
Rust buildup also weakens the blades, making them dull and less effective. Unfortunately, there’s no effective way to eliminate the corrosion. We’ll have to replace the rusted parts so the disposal can run smoothly again.
Loose or Misaligned Flywheel
A loose flywheel can knock against other components, generating a clattering or grinding sound. This is one of the rarer occurrences, but it sometimes happens in older units.
We can tighten or realign the flywheel so that everything operates as it should. If the flywheel continues to come loose, replacing the entire unit will be the best choice.
Hard Water Deposits
Many neighborhoods throughout San Jose, CA deal with hard water issues. The mineral deposits in the water tend to cling to metal surfaces, making garbage disposals especially vulnerable to scale buildup. As calcium and lime accumulate on the blades and chamber walls, they form rough, uneven layers. And when the impellers and shredder ring rub against them, they grind more harshly.
Professional descaling is effective in removing lime and calcium from garbage disposals. However, if the buildup is severe, this can make cleaning less effective. We may recommend installing a new disposal when descaling won’t restore full performance.
Cracked or Damaged Housing
The housing of the garbage disposal is what sits in the mounting bracket. Just like the bracket, the housing requires proper alignment to ensure all parts function correctly. Anytime it becomes cracked or warped, the internal parts will rub against one another, leading to major damage and loud noises. There’s also a much greater risk of leaks when the housing shifts out of place.
We can’t fix cracked housing—you’ll need a whole new unit. The best way to avoid this problem is to hire a skilled plumber to install the disposal and be careful not to overload it.
Book Yearly Inspections to Keep Your Disposal in Tip-Top Shape
Your garbage disposal is an investment that not only protects your plumbing but also affects your overall comfort and health. Booking an annual inspection is an easy way to spot problems in their early stages before they result in loud grinding noises and costly repairs.
Here are some of the different things we’ll do during an inspection to make sure the disposal functions properly year-round:
- Checking for leaks and water damage
- Tightening mounting hardware and connections
- Testing motor performance and bearings
- Inspecting impellers and shredder ring
- Looking for rust or corrosion inside
- Verifying proper electrical connections
- Flushing and cleaning the grinding chamber
- Running safety tests for reliable operation
Plumbtree Plumbing & Rooter offers expert support for garbage disposals and other plumbing services throughout San Jose. We have extensive experience installing, repairing, and maintaining plumbing systems in Santa Clara County. Call Plumbtree Plumbing & Rooter today to schedule a professional garbage disposal repair in San Jose.
