Step-by-step fix
Step 1: Confirm the noise matches this repair
- Run the dishwasher just long enough to hear the sound and note when it happens: right after filling, during washing, during draining, or all the time.
- Listen for a harsh grinding or rattling sound from the bottom of the tub rather than a light swishing sound from normal spray action.
- Open the door and check whether wash performance has also dropped, since weak wash action plus grinding often points to debris or a pump-area problem.
- Turn the dishwasher off before putting your hands inside.
If it works: You have confirmed the sound is an abnormal grinding noise and have a rough idea whether it happens during washing or draining.
If it doesn’t: If the sound is more of a hum, buzz, or water hammer noise, this is likely a different problem path than grinding.
Stop if:- You smell burning, see smoke, or find signs of melted plastic or damaged wiring.
- The noise is coming from a loose mounting bracket, cabinet contact, or another source outside the dishwasher rather than inside the tub.
Step 2: Clear the tub bottom and inspect the spray arms
- Remove the lower rack so you can reach the bottom of the tub easily.
- Spin the lower spray arm by hand and make sure it turns freely without rubbing dishes, a fallen utensil, or the tub.
- Look for broken glass, fruit pits, bones, labels, twist ties, or other hard debris around the spray arm and sump opening.
- If your dishwasher allows easy removal of the lower spray arm, take it off and rinse it out. Clear clogged spray holes with a soft brush or toothpick without enlarging the holes.
If it works: The spray arm turns freely and the tub bottom is clear of anything that could grind or rattle during the cycle.
If it doesn’t: If the spray arm is cracked, warped, or rubbing even when the tub is empty, it likely needs replacement.
Stop if:- You find a broken spray arm mount or damaged sump cover that will not hold the arm in place.
Step 3: Remove and clean the filter thoroughly
- Take out the lower filter assembly using the normal twist-lock or lift-out motion for your dishwasher.
- Rinse the filter under warm water and scrub off grease, paper labels, seeds, and grit from the mesh and frame.
- Wipe the filter housing and the area around it so loose debris does not fall back in when you reinstall it.
- Reinstall the filter securely so it sits flat and locks in place.
If it works: The filter is clean, seated correctly, and no loose grit remains around the opening.
If it doesn’t: If the filter will not lock, is torn, or has a broken frame, replace it before running another full cycle.
Stop if:- The filter opening reveals broken plastic pieces, a loose impeller cover, or obvious internal damage below the filter.
Step 4: Check the sump and pump area for trapped debris
- With power off to the dishwasher, use a flashlight to inspect the sump area below or beside the filter opening.
- Remove any visible debris carefully, especially glass shards, bone fragments, and small hard objects that can strike the impeller.
- If there is standing water, soak it up with towels or remove it with a wet/dry vacuum so you can see the bottom clearly.
- If your dishwasher has a removable sump cover or debris screen that is easy to access, take it off, clean underneath, and reinstall it exactly as it came apart.
If it works: The sump area is free of hard debris that could contact the wash or drain impeller.
If it doesn’t: If you cannot reach the debris safely, the next move is to stop and have the pump area opened more deeply for service.
Stop if:- You find a jammed impeller, broken impeller blade, or a cover that is cracked or will not reinstall securely.
- You would need to force apart hidden pump components to continue.
Step 5: Run a short test cycle and listen for the pattern
- Restore power and run a short rinse or quick cycle with the dishwasher empty.
- Listen during fill, wash, and drain so you can tell whether the grinding is tied to wash circulation or draining.
- If the noise happens during washing, open the door after the sound starts and check whether the spray arms were moving and water was circulating strongly.
- If the noise happens mainly during drain, the drain pump or something caught in it is more likely than the wash pump.
If it works: You have narrowed the problem to either debris that is now cleared, a wash-side issue, or a drain-side issue.
If it doesn’t: If the noise is unchanged after cleaning and still clearly comes from the pump area, the likely next step is pump or impeller diagnosis and possible part replacement.
Stop if:- The dishwasher leaks during the test cycle.
- The motor stalls, trips power, or makes a severe metal-on-metal grinding sound.
Step 6: Verify the repair holds in real use
- Run a normal load with dishes arranged so nothing hangs below the rack and touches the spray arm.
- Listen through the full wash and drain portions, not just the first few minutes.
- Check that dishes come out clean and that the dishwasher drains fully at the end.
- Recheck the filter after the cycle if you removed a lot of debris earlier, since leftover grit can wash back into the sump once more before it is fully cleared.
If it works: The dishwasher runs through wash and drain without grinding, cleans normally, and drains completely.
If it doesn’t: If the grinding returns in normal use, the root cause is likely a worn wash pump, drain pump, impeller, or damaged spray arm component rather than simple debris.
Stop if:- Grinding returns immediately after cleaning and is accompanied by weak spray, poor draining, or repeated tripping of the breaker.
FAQ
Why does my dishwasher make a grinding noise only during draining?
That usually points to debris in the drain pump or a worn drain pump. Small hard objects can get pulled into the pump and grind only when the machine is pumping water out.
Can a dirty filter cause a grinding noise?
Yes. A clogged or poorly seated filter can let hard debris reach the sump and pump area, where it can strike moving parts and create a grinding sound.
Is it safe to keep using a dishwasher that is grinding?
Not for long. A brief test to identify when the noise happens is reasonable, but repeated use can damage the pump, impeller, or spray arm if debris is trapped inside.
What if the dishwasher grinds and also has weak wash action?
That combination often means the wash side is affected. Check for blocked spray arms, a dirty filter, and debris in the sump first. If those are clean and the sound remains, the wash pump or impeller may be worn.
Do I need to replace the pump right away?
No. Start by clearing debris, cleaning the filter, and checking the spray arms. Many grinding noises come from something stuck in the lower wash area, not a failed pump.