It looks clean, sometimes smells only “a little off,” and works almost every day. But one of the most neglected places in the kitchen may be hiding inside the dishwasher: the filter.
Food residue, grease, standing water, and bacteria can build up at the bottom of the appliance, damage its ability to clean dishes, and create a bad smell that keeps coming back. The good news is that a simple cleaning that takes only a few minutes can change the entire story, reduce accumulated dirt, and help the dishwasher do what it is meant to do.
You put dirty dishes into the dishwasher, press a button, and assume that everything comes out clean at the end of the cycle. But if you have not cleaned the filter at the bottom of the dishwasher, some of yesterday’s food residue, last week’s leftovers, and perhaps even food from a month ago may still be there.
That residue does more than create an unpleasant smell. It can interfere with water flow, leave dirt on dishes, and create a moist, grease-rich environment where microorganisms thrive. The dishwasher has become one of the most convenient appliances in the home in recent years. It saves water, time, and effort, and when hot cycles are used, it can also help reduce the bacterial load on dishes.
Precisely because of its clean image, many people forget a basic point: The dishwasher does not fully clean itself. It washes dishes, but some food residue does not magically disappear. It reaches the filter at the bottom, the grooves, the door seals, the spray arms, and sometimes the pump area.
The problem usually begins with the filter. In many modern dishwashers, especially quiet and energy-efficient models, there is a manual filter designed to trap food residue, particles, grease, vegetable pieces, seeds, and crumbs. Its role is important: to prevent dirt from entering the pump and returning to the dishes.
When the filter is not removed and washed regularly, it turns from a protective system into a source of problems. Instead of stopping dirt, it begins to collect it. At that point, the first sign appears: a bad smell when the door is opened. Sometimes it smells like standing water, sometimes sour, and sometimes like a wet garbage bin.
Many people try to solve this by using dishwasher cleaner once a month, and that can certainly help remove grease and limescale. But cleaning liquid cannot always physically remove a piece of food stuck in or under the filter mesh. Just as a shower will not unclog a sink if a clump of dirt remains in the strainer, dishwasher cleaner will not always manage to break down a layer of organic dirt that has accumulated over weeks.
What does this mean for health?
It is important to be precise: A dirty dishwasher does not mean every meal is immediately dangerous. Most healthy people will not become ill simply because the dishwasher filter was not cleaned on time.
Still, food safety in the kitchen depends on many small actions. A neglected dishwasher contains an unwanted combination of moisture, heat, food residue, and grease. These conditions can allow bacteria, fungi, and mold to survive in certain areas of the appliance, especially around the seals and in areas that are not thoroughly washed during every cycle.
Studies that examined household dishwashers found that they are not sterile environments. Bacteria and fungi can be found in door seals, water, pipes, and the appliance's internal parts. This does not mean people should panic about their dishwasher. It means they should treat it like any wet kitchen appliance: clean it, air it out, and maintain it.
For families with babies, elderly people, people with weakened immune systems, or oncology patients, this care is even more important.
The second mistake is ignoring the dishwasher door seals. Most people clean the inside of the dishwasher only when it already smells bad, but the rubber strips around the door are a problem area.
Water and detergent do not always reach them with enough force, especially the lower part of the door and the edges. A sticky layer of grease, dirt, and mold can build up there. Wiping a damp cloth along the seal is often enough to show how much dirt is hiding there, even in a dishwasher that looks shiny from the outside.
The third mistake is using a short or eco cycle almost all the time. These cycles are important for saving electricity and water, but they do not always remove stubborn grease as effectively as a hot and intensive cycle.
When short or cooler cycles are used over a long period, grease from food can remain on the walls, in the pipes, in the filter, and in the spray arms. The result is more than a bad smell. Dishes may come out less clean, glasses may feel greasy, and cutlery may look as if it has been only partly washed.
The fourth mistake is sealing the door shut after every use. A dishwasher that has finished working remains warm and moist. If it is closed completely immediately after the dishes are removed, the moisture is trapped inside.
A closed and humid environment is exactly what mold and bad odors need. That is why it is worth leaving the door slightly open after the cycle ends, so the dishwasher can dry and air out. Some advanced models include automatic door opening at the end of the cycle, and it is worth checking that this option is activated.
There is another surprising mistake: over-rinsing dishes before putting them in the dishwasher.
Many people believe that dishes should go into the dishwasher almost clean. In modern dishwashers, the common recommendation is to scrape solid food residue into the trash rather than rinse every plate under the tap.
Excessive rinsing wastes water. In some cases, it can also interfere with sensors or reduce the effectiveness of enzyme-based detergents, which are designed to break down fats and proteins. Dishes should not go in with chunks of food on them, but they also do not need a full wash before entering the dishwasher.
What should you do tonight?
Start with the simplest action: Remove the lower rack, turn the bottom filter, and carefully pull it out.
In most dishwashers, the filter consists of a cylindrical element and a flat mesh. Wash it thoroughly under running water with a little dish soap and a soft brush or an old toothbrush. If you see a greasy layer, crumbs, seeds, or gray dirt, that was probably the source of the smell.
Next, check the area under the filter. In some dishwashers, there is a small cover that leads to the pump or drainage area. Do not force parts apart, and do not put your hands into unfamiliar areas. According to the manufacturer’s instructions, you can check whether there is dirt, standing water, a piece of glass, a seed, or a small bone.
If there is a very strong smell, flooding, water that does not drain, or unusual noise, stop and call a technician, especially if you are unsure how to remove and replace the parts.
The next step is cleaning the door seals. Take a damp cloth with a little soap, or a cleaning product suitable for kitchen appliances, and wipe along all the seals, especially the lower part of the door and the corners. If there is visible mold or a black layer, do not ignore it. Clean gently, dry well, and if the mold returns or the rubber is damaged, check whether the seal needs replacing.
After the seals come the spray arms. These are the “sprinklers” that rotate inside the dishwasher, sending water toward the dishes. When their small holes become clogged with food particles or limescale, water does not reach every area. The result is that entire sections of the dishwasher remain dirtier.
In most models, the lower arm can be removed by pulling it up, while the upper arm can be removed with a simple twist. Rinse them under running water and, if needed, gently open any blocked holes with a toothpick.
Only after the manual cleaning is done is it worth running a hot cycle. Once every two weeks, or at least once a month in a lightly used dishwasher, run a hot intensive cycle according to the manufacturer’s instructions.
If you use the dishwasher every day, cook often, or load dishes with a lot of grease, the filter should be cleaned more often, sometimes once a week or once every two weeks. In an average household, cleaning every two weeks to once a month is a reasonable goal. The smell is the clearest measure: If the dishwasher smells bad, do not wait.
The important message is to stop treating the dishwasher like a magic appliance. A working, clean, well-maintained dishwasher is an excellent tool for keeping dishes hygienic.
Health authorities note that when better sanitation is required, such as for baby bottles or during water contamination events, a hot cycle, heated drying, or a sanitation cycle can help reduce bacteria.
But even the hottest cycle does not replace cleaning the filter, the seals, and the areas where physical dirt simply remains stuck.
The rule is simple: Scrape solid food into the trash; do not rinse every plate until it shines; clean the filter regularly; air out the dishwasher after use; wipe the seals; check the spray arms; and run a hot cycle from time to time.
If, after all that, there is still a bad smell, dirty dishes, standing water, or recurring mold, the issue is no longer only about cleaning. It is a reason to check for a problem in the drainage, pump, pipes, or sealing.