Why Your Dishwasher Is Making a Grinding Noise and How to Fix It

That Grinding Noise Coming From Your Dishwasher Isn't Normal

You're loading dishes after dinner when suddenly your dishwasher kicks in with a sound like gravel tumbling in a metal drum. It's loud, it's unpleasant, and you're wondering if something's about to break. A grinding noise from your dishwasher is one of those sounds that gets your attention right away—and for good reason. It's usually telling you something needs attention before a small problem becomes an expensive repair.

In many homes, we see grinding noises caused by debris stuck in the pump or a failing motor bearing, but the actual culprit depends on when the sound happens and what it sounds like. The good news is that not every grinding sound means replacement time.

The Most Common Causes of Dishwasher Grinding

The dishwasher pump is the hardest working part of the machine. It's pushing water through spray arms, draining dirty water, and cycling water multiple times per load. When something goes wrong inside that pump, you'll hear it.

Foreign objects stuck in the pump: This is the number-one reason I find when I get called out for grinding noises. Glass shards, small pieces of bone, or even a bit of plastic from a takeout container can lodge in the pump housing. The pump tries to spin, hits the object, and creates that grinding sound. I once found a small pebble that came in on produce—something you'd never expect.

Worn pump bearings: Dishwashers that are 7 to 10 years old often develop worn bearings in the pump motor. Instead of spinning smoothly, the motor shaft rocks slightly, and metal grinds against metal. This typically sounds like a continuous grinding rather than an intermittent noise.

Damaged spray arm: The lower or upper spray arm can crack or wear through, and a loose fragment might rub against the tub or pump area. This creates a grinding or scraping sound, especially during the wash cycle.

Failing circulation motor: Some dishwashers have a separate circulation motor that moves water. When this motor bearing wears out, you get grinding noise combined with reduced water pressure during the wash.

What You Should Do First

Before you call for dishwasher repair, try these steps yourself. First, stop the cycle and let the machine drain completely. Check the very bottom of the tub—you'd be surprised how often debris settles there. Look for glass fragments, food particles, or anything that seems out of place. If you see something, carefully remove it.

Next, inspect the spray arms. Remove the lower rack and look at both spray arms. Spin them by hand—they should rotate freely and smoothly. If you feel grinding or resistance, that's your sign.

Run an empty cycle with hot water and see if the noise returns. Sometimes a one-time debris piece creates the sound, and once it's removed, the problem is solved. This takes 15 minutes and costs nothing.

When You Need a Technician

If the noise continues after you've cleared visible debris, or if it sounds like a continuous mechanical grinding rather than an intermittent scrape, don't wait. A worn pump bearing won't repair itself, and grinding metal inside an appliance only gets worse. Continuing to run the dishwasher can damage other components, turning a pump replacement into a much larger repair bill.

The same applies if you notice the dishwasher isn't draining properly alongside the grinding. That's usually a sign the pump is struggling and needs professional service.

Prevention Steps for the Future

Keep grinding noises from returning by rinsing dishes more thoroughly before loading. You don't need to pre-wash them completely, but removing loose food and debris reduces the chance of particles reaching the pump. Check your drain filter regularly—most dishwashers have a removable filter at the bottom that catches larger pieces. Clean it out every month.

Run a maintenance cycle monthly with a commercial dishwasher cleaner. This keeps the spray arms clear and the pump operating smoothly.

Bottom Line

A grinding dishwasher is almost always fixable, but the longer you ignore it, the more damage it can cause. Most grinding noises stem from debris or worn pump parts, both of which a technician can diagnose and repair. If you've checked for obvious blockages and the noise persists, schedule service before the problem spreads to other parts of your machine.

Quick Action Checklist: Stop the cycle and allow the dishwasher to drain fully. Check the bottom of the tub and remove any visible debris like glass or plastic. Inspect the spray arms for cracks or loose pieces. Run an empty hot water cycle to test if the noise returns. If grinding continues, contact a professional technician—don't run additional cycles while investigating.