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Why Is My Dishwasher Making a Knocking Noise?

Dishwasher Operating

Washing dishes is a tedious task. Dishwashers provide you with great convenience. They can help you save time and energy by cleaning your dishes.

However, it may also present you with challenges at times. One of the common examples is the high-pitched noises coming out every time you start your dishwasher.

Are you encountering the same problem? Is your dishwasher making weird noises?

If you are looking for ways to get rid of the irritating rattling sound, continue reading this article.

The first step to prevent your dishwasher from making that knocking sound is to find the reason behind it.

Once identified, you can move on to the right measures to get the problem fixed.


This article aims to help you identify the problems causing the knocking sounds of your dishwasher.

  • The dishwasher parts may be damaged or loose.
  • There might be foreign objects in the dishwasher.
  • The dishes might be loaded incorrectly.

Once identified, you can take the right steps in to rectify the problem.

Is your dishwasher making knocking sounds? Let’s identify the reasons behind the grinding sound and fix them together.

3 Major Reasons Why Your Dishwasher Makes Knocking Sounds

Man Repairing The Dishwasher

Dishwashers often make a splashing sound while washing the dishes. However, if the noise is other than just water splashing, it can be a signal of some problems.

The unwanted sounds not only affect the quality of your life but also indicate some serious issues with the dishwasher itself.

Let’s discuss the potential reasons one by one.

1. Foreign Object Stuck in the Dishwasher

Man Cleaning The Dishwasher Filter

A very important reason behind a noisy dishwasher can be any foreign object stuck inside the washer.

It can be any small utensil, food debris, a toy, or a bone that has fallen into the dishwasher. During each wash cycle, the item may move around, creating weird sounds.

To get this problem fixed, all you need is to open the dishwasher and look around closely for any strange object.

Once you have found it, you can remove it and properly dispose of it.

Pro Tip!

Nip this issue in the bud before it can grow into a full-blown problem!

Clean your dishwasher once every week. Make sure to clean any debris or food particles stuck in the drainage to prevent clogging.

Not only will this solution eliminate the problem but it will also keep your health good.

If the problem still persists, you can take a look at the further causes.

2. Problem With Dishwasher Parts

Man Tightening The Screws Of The Dishwasher

Due to the frequent usage of the dishwasher, some of its parts may get loosened or damaged over time. The parts more prone to such damage are listed below:

  • Wash Arm: It splashes the water and detergent over the dishes during each wash cycle to wipe the unwanted material off them. Since the wash arm has to move around during the wash cycles, it can make crackling sounds if it is loose or damaged.
  • Spray Arm: The purpose of the spray arm is to direct the water flow over the dishes and other items in the washer. Its loosening or damage can create unusual sounds.
  • Drain Pump: The drain pump allows the release of water from the washer once the cleaning is done. A rusty or damaged pump can result in the production of an unpleasant strange noise.
  • Chopper Blade: It is responsible to cut the solid waste into small pieces before releasing it into the draining pipe to prevent its blockage. Anything hard stuck in the blade can create a grinding noise which can be too loud at times.

A good observation of the above parts can help you recognize the problematic area and utilize the best possible solution.

You can tighten the screws using the basic tools or replace the damaged part by following the manufacturer’s instruction booklet.

Once the work is done, you can check again whether the problem is resolved or not.

3. Incorrect Loading of Dishes

Woman Loading The Dishes In The Dishwasher

Sometimes, incorrect loading of the dishes and utensils can be the reason behind the knocking noise.

If dishes are not loaded properly, they might bang into each other or bump into the walls of the dishwasher, making a thumping noise.

To resolve this problem, pay attention to your dish-loading style.

Preventive Measures

Here are a few reminders to follow when loading dishes in the dishwasher:

  • Do not stack too many dishes in the dishwasher at one time.
  • Make sure the dishes are not packed too close to one another.
  • Dishes must not be touching the dishwasher’s walls, nor placed too close to them.

Always make sure the dishes are amply spaced to allow circulation of the water and detergent as well as to prevent them from colliding during the wash cycles.


A knocking sound in a dishwasher can be an annoying issue. It can be due to the following reasons: a foreign object stuck in the dishwasher, a problematic part of the dishwasher, or incorrect loading of dishes.

By identifying the problem and by following the above-mentioned steps, you not only fix the noise but also prevent any major problems in the future as well.

Frequently Asked Questions

How Can I Fix a Knocking Noise Caused by a Loose or Damaged Part of a Dishwasher?

To fix a knocking noise caused by a loose or damaged part of the dishwasher, perform the following steps:

  • Check for any loose/damaged parts.
  • Tighten the loose parts.
  • Replace the damaged parts with new ones.

Make sure to follow the manufacturer’s guide whenever tightening/replacing a part to prevent any missteps.

Can a Knocking Noise in the Dishwasher Be a Sign of Danger?

The knocking sound can be a sign of danger if it is caused by a faulty part. Make sure to take preventive measures by following the steps written in the article.

If you are still unable to solve this issue, it is recommended to seek the help of a professional technician.

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