How Does a Dishwasher Work?

Even though most of us rely on our dishwashers almost daily to clean our dishes, not many people really know much about how dishwashers work. When you have a better understanding of how your dishwasher operates, you’ll be able to care for your appliance and troubleshoot problems more quickly.

Read on to learn everything you need to know about how a dishwasher works.

If you’re ready to replace your appliance, browse our full selection of dishwashers to find options from leading brands.

In this article, we’ll cover:


  • What Are the Different Parts of a Dishwasher?
  • How a Dishwasher Works Step by Step
  • FAQs About How a Dishwasher Works

What Are the Different Parts of a Dishwasher?

What happens when you shut the door of your dishwasher and start a new wash cycle? How does a dishwasher work inside? Do dishwashers use electricity?


These questions may have popped into your mind from time to time. The truth is, your dishwasher is able to clean dishes and tackle tough stains thanks to several key components and parts:


  • Control panel: This is the panel that allows you to select which settings you want for each wash cycle. The control panel can be located on the front or top of your dishwasher’s door, depending on your model.
  • Detergent dispenser: Before you start a new wash cycle, you’ll need to add a cleaner to the detergent dispenser. Many dishwashers have a rinse aid dispenser as well.
  • Heater: The temperature inside a dishwasher can change thanks to its internal heating element. This allows dishes to be washed at very high temperatures for sanitary and powerful cleaning purposes.
  • Circulation pump: Water from your plumbing is pushed into the dishwasher via the circulation pump.
  • Filtration system: To prevent the pump from clogging, the filtration system will filter out large pieces of food. This system also removes dirty water from the dishwasher.
  • Water inlet valve: This valve can be found on the interior of your dishwasher, where it controls how much water is used during a wash cycle.
  • Wash arm: These rotating arms help circulate water throughout the dishwasher. While most models have two arms, some newer models may have a third arm.
  • Racks: Dirty dishes are safely stored on racks inside the dishwasher until they’re ready to be cleaned. Many models also have a removable basket for silverware.
  • Door latch: Once a wash cycle is activated, the door latch seals the door shut to prevent leaks.


Most, if not all, of these parts, can be found in almost any dishwasher, but certain types of dishwashers – like portable and countertop models – may operate a bit differently. How do portable dishwashers work? Most models can be connected to the sink and use water from the faucet, but there are some units that have built-in water tanks.

How A Dishwasher Works - Step by Step

Now that you’re familiar with some of the parts inside your dishwasher, it’s time to look at how these parts work together. If you’ve ever asked questions like “How do dishwashers work,” this guide has the answers.


Step 1: Heating the Water

After you start a wash cycle, the circulation pump will begin to fill the dishwasher with water. As the dishwasher fills, the heater raises the temperature of the water until it’s hot enough to sterilize dishes.


Step 2: Running the Rinse Cycle

Once the water is at the appropriate temperature, the wash arms will circulate water across the dishwasher, rinsing off your dishes. This step helps loosen and remove food particles before the dishes are washed.


Step 3: Distributing Detergent

Before the main wash cycle begins, the detergent dispenser will open, releasing the cleaning solution inside. The detergent will immediately come into contact with the hot water inside the dishwasher, creating soapy suds.


Step 4: Main Wash Cycle

During this step, your dishes will be repeatedly sprayed with hot, soapy water. Dirty water is filtered out automatically, and dishes are sprayed with fresh water until the cycle is complete.


Step 5: Drying Dishes

When the main wash cycle is over, any remaining water is drained away. The temperature inside your dishwasher will rise, producing hot air that helps dishes dry quickly.

FAQs About How a Dishwasher Works

Do dishwashers require electricity?

Although there are some specialty manual types on the market, nearly all dishwashers need electricity to operate. A typical dishwasher uses, on average, about 1.2 kWh/hour (for a 1200-watt model). That works out to roughly $2.40/month if you run your dishwasher 5 days per week.  

Do dishwashers reuse water?

While dirty water is drained from the dishwasher during the wash cycle, dishwashers are able to recycle and recirculate water during the cycle. Dirty water is pushed through a filter to remove most of the particles and waste and then the clean water is pushed back into the dishwasher.

How do dishwashers know how dirty dishes are?

While most older dishwashers follow a program, many newer models are equipped with a device called a turbidity sensor. This sensor tests water as it’s pushed out of the dishwasher to see if it’s dirty. Once the water is clean, the sensor signals that the wash cycle is complete.

Why does my dishwasher run for 2 hours?

The length of a wash cycle can vary based on your dishwasher model and chosen settings. Keep in mind, some models may have a shorter wash cycle and other dishwashers can run for as long as 2 hours.

Do dishwashers use less water than washing up by hand?

Since dishwashers recycle water, running a load of dishes actually takes far less water than hand washing would. It can take up to 27 gallons of water to hand wash a load of dishes vs a dishwasher’s typical 3 gallons per cycle.

How long is a normal wash cycle on a dishwasher?

The average wash cycle is between 2 and 4 hours. However, since many dishwashers are now equipped with sensors that can detect when dishes are clean, it’s possible for a dishwasher cycle to be much longer or shorter.


While homeowners don’t have to be dishwasher experts, learning the answer to questions like “how do dishwashers work” can be surprisingly helpful. When you have a better understanding of how dishwashers operate, you can get to the bottom of problems and give your appliance the care it needs.


Now that you’ve learned more about how dishwashers function, browse our full selection of dishwashers to find the right unit for your home.