You love your dishwasher—but do you know how a dishwasher works? Most of us simply close the door and turn it on, never giving the machine another thought. But understanding how a dishwasher works can help you use it more effectively and improve the cleanliness of your dishes.
Understanding the Inside of a Dishwasher
How does a dishwasher work? If you take a look inside of your dishwasher or study the diagram of a dishwasher, you’ll likely see a few racks with a rotating piece on the bottom, but dishwashers are much more complex.
Each part of a dishwasher must work in synchronicity to achieve a thorough clean and sparkly shine. The parts inside of a dishwasher include:
- Heating element: The heating element is what enables your dishwasher to heat water. It sits at the bottom of the dishwasher and controls the temperature of both the water that washes your dishes and the air that dries your dishes. Without this, your dishwasher would wash with mild water and be much less effective.
- Water inlet valve: This is how water gets into your dishwasher. It sits in the corner of the machine and controls the flow of water.
- Spray arms: This vital part of your dishwasher sits beneath each rack and sprays water on the dishes to remove food and soap.
- Filtration system: The filtration system is responsible for removing any leftover pieces of food from your dishes, ensuring they come out clean and don’t cause clogs. This system is also able to clean dirty water, allowing it to recirculate back through the dishwasher.
- Circulation pump and motor: This regulates water pressure and direction of water flow in both the spray arms and the filtration system.
- Detergent and rinse aid dispenser: If you’ve ever used a dishwasher, you’re familiar with this part–it’s where you put your dish detergent and any other cleaning products you use during a dishwashing cycle. In most models, the dispenser sits inside of the dishwasher’s door, releasing detergent and rinse aid products during the washing process.
- Control panel: Depending on your model of dishwasher, the control panel may be located on the front or the top of the dishwasher door. This is where you’ll select your preferred dishwasher settings. In newer models, it also lets you know how much time is left in the cycle.
- Racks and supports: Another part you’re likely familiar with, the racks are where you load your dishes. They sit in a track that allows you to move them in and out of the dishwasher for easy loading and unloading. Racks often come with accessories, like baskets to hold silverware.
Step-by-Step: The Dish Cleaning Process
Now that we understand the various parts inside your dishwasher, let’s review how a dishwasher works. Generally speaking, a dish cycle is divided into 3 stages. Much like manually washing dishes, your dishwasher washes, rinses, and dries.
Step One: Wash
The first step in a dish cycle is where the cleaning happens. This stage is the most complex.
During the soap stage:
- The water inlet valve floods the basin at the bottom of the dishwasher with clean water.
- The spray arms spray each rack of dishes for a pre-rinse to remove any leftover food.
- The heating element heats the water at the bottom of the basin to the programmed temperature.
- The detergent and rinse aid dispenser release detergents into the heated water.
- The circulation pump and motor push the soapy water into the spray arms intake and use it to spray the dishes.
- The circulation pump and motor reverse the direction of the water and the dirty water drains.
Step Two: Rinse
Once the dirty water is fully drained, the water intake valve releases hot, clean water into the dishwasher. Again, the circulation pump and motor push this water into the spray arms, which spray the soapy dishes with clean water.
Step Three: Dry
Once again, the circulation pump reverses direction and pumps the rinse water out of the dishwasher. In a standard cycle, the residual steam from the hot water that is used to wash the dishes also dries them. Some models also have a fan to speed up the drying time.
Pro Tip: Use the Finish® JET-DRY® rinse aid to boost your machine’s rinse and dry cycle for best results.
Additional Features
Modern dishwashers offer a range of settings that modify the above process to achieve different results. These may include:
- “Eco” settings: These settings lower how much energy a dishwasher uses by lowering the temperature of the water. Despite using cooler water, eco settings are typically effective enough to wash small, normally soiled dishes, but may be too gentle for large dishes or baked-on grime. Eco settings also tend to take a bit longer, so if you’re wondering why your dishwasher takes so long, you may want to check your selections.
- Sanitizing settings: If you’re looking for that extra clean, a sanitizing setting might help. These add extra-hot water to the rinse cycle, taking your clean to the next level.
- Air dry: The air dry setting is a modern invention that releases the door latch at the end of the cycle, allowing the door to open and built-up steam to escape. Not only can this dry your dishes more quickly, but it may help avoid water spots for a more sparkly shine.
- Rinse only: A great solution for homes that run their dishwasher infrequently, this cycle offers a quick, powerful spray of water to building dishes, removing any excess food odors along with it.
How Does a Dishwasher Work: FAQs
Can I run my dishwasher without hot water?
If you’re still wondering, “do dishwashers use hot water?” The answer is yes, and for good reason.
While there are settings that lower the temperature of your dishwater in order to save energy, it isn’t recommended to run your dishwasher with cold water. Hot water helps unstick food from your dishes and creates the steam needed to dry them.
Do dishwashers fill up with water?
How much water does a dishwasher use? Maybe not as much as you think. The dishwasher doesn’t fill up with water, just the bottom basin does.
Do dishwashers recirculate water?
Dishwashers are able to recirculate water. As dirty water is drained from the dishwasher, it’s run through the filtration system to remove any bits of food. The cleaned water then re-enters the dishwasher.1
What are the disadvantages of a dishwasher?
While dishwashers are a lifesaver for busy families, they do have some downsides. Dishwashers can be expensive and also drive up the cost of your energy bill. In some cases, the dishwasher might take longer than washing your dishes by hand, but the only thing you have to do is load it, put the detergent in and start the cycle. You'll end up saving water and time!
How long do dishwashers usually last?
A dishwasher should last about 10 years, but keep in mind that they may need some repairs along the way. According to a Consumer Reports survey, about 25% of dishwashers either broke or became less effective within five years. 2
Wrapping Up
A deeper understanding of your dishwasher can help you achieve a better clean. The right detergent products can, too. Explore premium detergents from Finish®, like Finish® Ultimate, to remove the toughest stains and achieve the ultimate clean.
- "How Does a Dishwasher Work?" Coast Appliances, Coast Appliances,
www.coastappliances.ca/blogs/learn/how-does-a-dishwasher-work.
Accessed 24 Sept. 2024. - "How to Make Your Dishwasher Last Longer." Consumer Reports, Consumer Reports,
www.consumerreports.org/appliances/dishwashers/how-to-make-your-dishwasher-last-longer-a7937722178/.
Accessed 24 Sept. 2024.
