How Does a Dishwasher Work?

Jul 22, 2023, 12:59pm

The dishwasher is a complex device but its operation is the same for all models and has hardly changed since its creation. Its invention dates back more than a century and greatly facilitates family life by reducing the duration of household chores.

Here we explain how a dishwasher works by detailing all the steps of a washing cycle and breaking down the main spare parts of the appliance.

A dishwasher is a modern kitchen appliance that has revolutionized the way we clean our dishes. It offers convenience and efficiency, allowing us to save time and effort in our daily chores. But have you ever wondered how this appliance works its magic to transform dirty and greasy dishes into sparkling clean ones? In this article, we will explore the inner workings of a dishwasher and how it efficiently cleans your dishes.

How Does a Dishwasher Work?

1. Loading the Dishwasher

The first step in using a dishwasher is loading it with dirty dishes and utensils. It is essential to arrange the dishes properly to ensure effective cleaning. Large items like pots and pans should be placed at the bottom, while plates, bowls, and glasses go on the top rack. Cutlery and small items can be placed in a dishwasher basket.

2. Pre-Wash and Soaking

Before the main cleaning cycle begins, some dishwashers have a pre-wash or soaking phase. During this phase, the dishwasher sprays water on the dishes to loosen and soften any dried-on food particles.

3. Detergent Dispensing

Once the pre-wash phase is complete, the dishwasher’s detergent dispenser releases the detergent into the dishwasher. The detergent is a crucial element in the cleaning process as it helps to break down and remove grease, stains, and food residues from the dishes.

4. The Main Cleaning Cycle

The main cleaning cycle begins after the detergent has been dispensed. Here’s how it works:

  • Water Inlet: The dishwasher’s water inlet valve opens, allowing hot water to enter the dishwasher. Hot water is preferred for its effective cleaning properties.
  • Spray Arms: The dishwasher has two or three spray arms, depending on the model. These spray arms are equipped with small nozzles that direct the hot water to the dishes. The water pressure and the rotating motion of the spray arms ensure that every dish is thoroughly cleaned.
  • Detergent and Water Mixture: The detergent mixes with the hot water, creating a soapy solution that effectively cleans the dishes.
  • Rinsing: After the cleaning process, the dishwasher goes through multiple rinsing cycles to remove the detergent and any remaining residues from the dishes.
  • Drainage: Once the rinsing is complete, the dirty water is drained from the dishwasher through the drain pump.

5. Drying Phase

After the dishes are cleaned and rinsed, some dishwashers have a drying phase to remove excess moisture from the dishes. There are two common drying methods:

  • Heated Drying: In heated drying, the dishwasher uses a heating element to warm the air inside the dishwasher, evaporating the water from the dishes.
  • Air Drying: Some dishwashers use natural air drying, where the dishes are left to air dry. The residual heat from the hot water and the warmth of the dishwasher’s interior help evaporate the water from the dishes.

6. Completing the Cycle

Once the drying phase is complete, the dishwasher will signal that the cleaning cycle has finished. You can then open the dishwasher door and unload your clean and dry dishes.


There are different steps that happen before your dishwasher’s wash cycle starts:

  • Draining takes place before your wash cycle starts. This is an important step for the durability of your appliance, because it is the precise moment when it removes any liquids that have appeared when placing dirty dishes in the storage bins.
  • The solenoid valve authorizes the arrival of water which fills the dishwasher according to the quantity necessary and recommended by the manufacturers. The pressure switch and a float system ensure the correct water level. On some models a filler coupled to a flow meter replaces the float system.

These two steps have initiated the washing cycle, which will finally be able to begin:

After mixing with the detergent in the detergent box, the spilled water is now sucked up by the cycling pump and distributed inside the rotating arms.

  • The temperature sensor controls the heat of the machine and maintains the temperature once the heater begins to heat the water.
  • Once the ideal temperature is reached, the heat, the jets of water and the detergent can loosen the soils from the dishes.

Once the washing cycle is finished, waste water disposal takes place during emptying. The amount of water in the machine remains under the control of the pressure switch.

After that, the rinsing begins:

  • Its course is quite similar to the washing cycle, that is to say that the water fills and goes to the rotating arms. The difference here is that the water is not heated and remains cold. Draining takes place again.
  • A final hot rinse is required. The dishwasher heats up to the temperature set by the manufacturers. Then, the rinsing liquid is recycled and mixed with water for another rinsing, useful for drying. The water drains one last time.For impeccably cleaned dishes, the last step is drying. Depending on the devices, different methods are used, which will not consume the same amount of energy:
  • First of all, there is the so-called “natural” drying. The water vapor condenses either on its own on the walls of the dishwasher, or with the help of cold water which will precipitate the condensation.
  • Alternatively, a fan can be used to blow all the water to the bottom of the dishwasher.

How Does a Dishwasher Work?


Parts of a dishwasher can be divided into several groups:

Parts for regulating the temperature and quality of water, as well as its cleaning action:

  • The cycling arms: also known as reels, they project water onto the dishes and provide an effective mechanical cleaning action.
  • Resistance: also called immersion heater, this part is used to heat the water in the dishwasher.
  • The drain filter: it collects and retains all dirty particles and other impurities. This is why it is located below the basket at the bottom of the dishwasher and in the bottom of the tub.
  • The salt pot: Thanks to it, the washing water can be softened when filling the dishwasher.

Parts that detect states and realize device safety:

  • The solenoid valve: This is an important part because its role is to control the water supply to the machine. It allows the tank to be filled and secures the water level thanks to an anti-overflow system. It is also used to regenerate and supply the salt pot.
  • The thermostat: It controls the temperature of the water in your dishwasher.
  • The pressure switch: It detects the presence of water and manages the quantity of water authorized. Then, it transmits the authorization to the thermostat to heat the water.
  • Door safety: In addition to securing the engagement of the dishwasher, it allows the circulation pump to be stopped when the door is opened.Device pumps:
  • The drain pump: It allows the evacuation of waste water once the cycle is finished.
  • The circulation pump: This part is one of the most important because it sucks up the water before propelling it into the wash arms.


A dishwasher’s inner workings are a harmonious blend of hot water, detergent, and mechanical action to efficiently clean and sanitize your dishes. From pre-wash to drying, each phase plays a vital role in the cleaning process. Understanding how a dishwasher works can help you use it effectively and enjoy the convenience and benefits it brings to your daily kitchen routine. With a dishwasher, you can say goodbye to the hassle of handwashing dishes and embrace a more convenient and time-saving way to keep your kitchenware clean and ready for use.