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Dishwashers usually make a soft humming noise when running and this is pretty normal. But, when it starts humming loudly, it might have you concerned.
Why is the dishwasher humming so loud? Is something wrong? Is it about to go bad?
Well, worry not.
In this guide, I will take you through what the loud humming noise means and what you can do about it. Additionally, I will also guide you through some other noises that your dishwasher might make and how to troubleshoot them.
Why is my dishwasher making a loud humming noise (plus how to quiet a noisy dishwasher)
A dishwasher that is making a loud humming noise can mean one of three things:
- Water is not flowing into the dishwasher
- Something is caught in the drain pump
- The dishwasher’s cabinet insulation might be bad
Now that we have an idea of what might be causing the loud humming noise you are hearing, let us have a closer look at how you can troubleshoot and fix the issue.
Confirm that water is flowing into the dishwasher
It’s worth mentioning that this is the most common cause for your dishwasher making a loud humming noise when starting… Lack of water flowing into the unit.
Of course, you should start by confirming that the water faucet is fully open.
Next, carefully inspect the water inlet hose and straighten out any kinks that it might have.
If you note that the inlet hose is bad – maybe it has a leaking hole, you can try to patch it up. If this does not work, your best bet is to get a quality replacement hose.
If the hose seems fine, proceed to confirm that the water inlet valve is working.
To do so, start by confirming that the valve is getting enough power – 110 to 120v AC.
If the power is not enough, check for any broken wires and be sure to fix them.
Next, check for continuity across the valve solenoids… No continuity implies that the valve is bad. In this case, I’d recommend swapping out the valve.
To point you in the right direction, I have compiled a list of quality valve replacement parts for a few common dishwasher brands:
| Dishwasher brand | Water inlet valve replacement part |
| Samsung | Buy it on Amazon |
| LG | Buy it on Amazon |
| Whirlpool, Maytag, Amana & Kenmore | Buy it on Amazon |
| Frigidaire | Buy it on Amazon |
| GE | Buy it on Amazon |
| Kenmore | Buy it on Amazon |
| Bosch | Buy it on Amazon |
Check if something is caught in the drain pump
On the other hand, if water is flowing into the dishwasher, odds are that something is caught in the drain pump.
And, the loud humming noise you’re hearing is most likely the drain pump’s motor running as it tries to drain.
To fix this, start by straightening any kinks that might be along the drain hose.
Something else: If your drain hose is not connected to an air gap, make sure that it has a high-rise loop that is at least 32” in height as shown:
Quick tip: The high-rise loop prevents water backflow which would otherwise make drainage hard.
If this checks out, proceed to turn off power to the dishwasher and remove the drain pump.
Once you get the drain pump out, carefully clean out any foreign objects that might be caught in there.
Inspect the dishwasher’s cabinet insulation
Some dishwashers – such as Samsung dishwashers – have a cabinet insulation fabric that covers the outside of the dishwasher.
The main purpose of this fabric is usually to dampen sound and hold in the heat.
When this fabric wears out, it might result in your dishwasher making the loud humming/buzzing noises you are hearing.
In this case, you can opt to either withstand the noise or change the insulation cover.
And there you have it!
Now, earlier on I had promised to also look at a few other noises your dishwasher might make and what they mean. Well…
Other dishwasher noises and what they mean
Dishwasher is making a buzzing noise / dishwasher making loud grinding noise
Buzzing and grinding dishwasher noises are similar to humming noises.
As such, if the noises are low, you do not have to worry about it since it’s normal.
On the other hand, if they become too loud, be sure to try the above recommendations and see if this fixes it.
Dishwasher making whining/whistling noises
As water runs through the pipes, it can make some high-pitched sounds such as whining and whistling.
In other words, whining sounds should not worry you especially when the dishwasher is filling with water.
However, if you note that your dishwasher is making loud whining sounds during the dry cycle, it’s advisable to clean the dishwasher and remove any plastic/debris that might be at the bottom of the dishwasher.
Dishwasher doors making squeaking noises
For the most part, a squeaking dishwasher door points to friction in the door hinges.
The good news is that you can quickly fix the issue by applying a food-safe lubricant (not WD-40) to the hinges.
Dishwasher makes tapping, knocking, or banging noises
These sounds usually occur when there is a foreign object inside the dishwasher tub or a utensil (such as a spoon) is hanging from the racks.
And, the knocking sounds you are hearing are due to the spray arms hitting the object during washing. However, at times it could also be due to the object hitting the dishwasher walls as the water circulates.
Having said that, you can fix tapping, knocking, and banging dishwasher noises by rearranging any utensils (such as spoons) that might have fallen or are hanging from the racks.
Also, you can check for loose filters that might be bouncing inside the dishwasher and firmly insert them into place.
Why is my dishwasher squealing?
Squealing/rattling dishwasher noise will mostly occur if the dishwasher is new – when it does not have any water in it.
And, this might be what is causing the squealing/rattling sounds you are hearing.
Nonetheless, you might also hear the sound if you are running your dishwasher for the first time after an extended period of not using it.
So, how do you fix dishwasher squealing noises?
Before running the dishwasher, pour two quarts of water into the bottom of the tub… The water will lubricate the pump seals thereby killing the squealing sounds.
Why is my dishwasher making a loud humming noise – recap
It’s common for a dishwasher to make low humming noises. However, loud humming noises may mean one of the following:
- The dishwasher is not getting any water
- There might be something trapped inside the drain pump
- The cabinet insulation might be bad
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