A dirty filter is the number one cause of dishes with residue, cloudy glasses, and bad odours. Where to find it, how often to clean it, and how to do it properly in just a few minutes.
If dishes come out with grainy residue, glasses remain cloudy, or you smell a bad odor when you open the door, in almost all cases the culprit is one: a dirty filter. It's the part that collects food residue at the end of the wash cycle, and when it clogs, water circulates back dirty instead of being filtered.
The good news is that cleaning it takes only a few minutes, requires no special tools, and there's nothing to disassemble invasively. In this guide, we'll see where the filter is located, how often to clean it, and how to do it step by step without risking damage.
The short answer. Remove the filter assembly from the bottom of the tub (usually by rotating the cylindrical part counterclockwise), separate the two or three components, rinse them under running water with the help of a soft brush, reassemble everything making sure the filter locks in place. A quick check every one or two weeks and a more thorough cleaning at least once a month are sufficient for normal domestic use.
In brief: what you'll find in this guide
How often to clean the filter
There's no rule that works for everyone, because it depends on how often you use the dishwasher and how dirty the dishes you load are. As a practical reference for domestic use:
| Dishwasher use | Recommended check |
|---|---|
| Intensive use (1 cycle per day or more) | Quick check every week |
| Medium use (3-4 cycles per week) | Check every two weeks |
| Occasional use | Check once a month |
Beyond a fixed frequency, there are signs indicating it's time to act immediately: food residue on dishes at the end of the cycle, bad odor when the dishwasher is off, water pooling at the bottom of the tub, or washing that has become less effective for no apparent reason. In many manuals, manufacturers simply state to check the filter "regularly": in practice, this means a quick look often is better than rare and difficult cleaning.
Where the filter is located and what it looks like
The filter is located at the bottom of the tub, usually in the center, under the lower spray arm. To reach it, simply remove the lower basket. In the vast majority of modern dishwashers, the filter assembly consists of several parts that work together:
Cylindrical filter (or central microfilter): the part you grip and rotate to remove the assembly. It traps fine residue and impurities.
Coarse filter: a wider-mesh element, often fitted into the cylinder, that catches larger food residue.
Flat filter (plate microfilter): the fine mesh that covers the drain opening and rests on the bottom when you remove the cylindrical assembly.
The exact combination varies from model to model, but the logic is always the same: one or more removable filters over a filter plate that protects the drain pump. To understand exactly how to disassemble yours, the most reliable reference is the manufacturer's user manual, which almost always includes diagrams showing the correct direction of rotation.
What you need
Lukewarm running water;
a soft brush, an old toothbrush works fine;
some dish soap or white vinegar for stubborn cases;
optionally a toothpick to clear the spray arm nozzles.
You don't need aggressive products or abrasive sponges: the metal and plastic mesh of the filter will be damaged if rubbed with rough materials.
How to clean the filter step by step
Turn off the dishwasher and make sure the cycle has finished. If you've just washed, let it cool for a few minutes: the water at the bottom can be hot.
Remove the lower basket to gain free access to the bottom of the tub.
Extract the filter assembly: grip the central cylindrical part and rotate it counterclockwise about a quarter turn until it unlocks, then lift it up. You'll often find arrows or unlock symbols on the basket or filter itself.
Remove the flat filter plate that remains resting on the bottom by lifting it gently.
Separate the components of the assembly (normally the cylinder separates from the coarse filter with a slight rotation or pressure).
Rinse everything under running lukewarm water, brushing the mesh with a soft brush. If there are deposits of grease or limescale, soak the pieces for a few minutes in hot water with a bit of dish soap or vinegar.
Check the drain pit, which is the seat under the filter: remove any food residue, glass fragments or pits that may have ended up there by mistake.
Reassemble in reverse order: first the flat plate, then the cylindrical assembly, rotating it clockwise until you feel it lock. This step is important: a filter that isn't engaged correctly allows residue to pass through and can make noise during washing.
Spray arms and nozzles: don't forget them
The filter is the part that gets the dirtiest, but thorough cleaning also involves the spray arms, the ones that spray water while rotating. Their nozzles become clogged with limescale and small residue, reducing pressure and therefore washing quality.
In most models the arms can be removed without tools, by unclipping them or unscrewing a central lock. Rinse them under water and clear any blocked holes with a toothpick, without enlarging them. Always check that once reassembled, they rotate freely. Here too the manufacturer's manual indicates the correct engagement system.
Seals, salt and rinse aid
With the filter out, take the opportunity to clean two often overlooked points:
The door seal: wipe a damp cloth along the rubber edge, where grease and residue accumulate and generate bad odour. It's the same principle as washing machine maintenance.
Regenerating salt and rinse aid: check the levels. A softening system without salt promotes limescale, which in turn clogs filters and nozzles. Limescale is the number one enemy of dishwasher longevity.
If you often notice streaks on glasses even after cleaning the filter, the problem may be related to salt and rinse aid or water hardness: we discuss this in detail in the guide on cloudy glasses in the dishwasher.
Mistakes to avoid
Using abrasive sponges or scourers: they damage the mesh and reduce filtering capacity.
Reassembling the filter without locking it: this is the most common cause of dirty dishes after cleaning and strange noises.
Running an empty wash with aggressive products thinking it will "replace" manual cleaning: a sanitising cycle helps, but doesn't remove solid residue trapped by the filter.
Ignoring the drain pit: this is where fragments end up that can damage the pump.
Forcing components apart: if a component won't come loose, check the manual instead of pulling. Every system has a precise direction.
The Portos summary
Filter cleaning is the maintenance task with the best ratio between time spent and result: five minutes every one or two weeks prevent poor washing, bad odours and, in the long run, pump damage. It's not a technical operation and doesn't require professional help: it's part of normal use, just like emptying the basket.
The practical advice is to make it a habit, not an extraordinary intervention. A clean filter and a salt-rinse aid system in order keep your dishwasher efficient longer and also protect your consumption, because an appliance that washes well on the first cycle doesn't force you to repeat the wash.
Also read: how to choose a dishwasher, how much a dishwasher consumes and, for the washing machine, how to clean the washing machine filter and seal.
Sources
User and maintenance manual for your dishwasher (manufacturer's document supplied with the appliance), filter and spray arm cleaning section.
Bosch Domestic Appliances, support and maintenance section: bosch-home.com.
Electrolux, appliance care and support area: electrolux.it.
