Do your dishwasher tablets seem useless? Are you unloading the dishwasher only to find glasses with marks, or plates still greasy? You’re not alone. A dishwasher not cleaning properly is one of the most common kitchen complaints. Sometimes it’s caused by everyday user mistakes — like overloading or blocked spray arms — but it could also be due to a faulty part or poor water pressure.
In this guide, we’ll explain why your dishwasher isn’t cleaning dishes as it should, and what you can do to get spotless results every time.
Why is my dishwasher not cleaning dishes properly? Most common causes
Let’s start with the most common issues linked to everyday use and a lack of regular maintenance. In many cases, a dishwasher that’s not cleaning dishes properly isn’t broken — it just needs a few small adjustments or a good clean. By avoiding these simple mistakes, you can often fix the problem yourself and get sparkling clean results without calling in a repair technician.
Incorrectly loaded dishwasher
Trying to cram too many dirty dishes into the dishwasher to avoid running a second cycle? You’re not alone — but overcrowding is one of the main reasons a dishwasher doesn’t clean dishes properly. When items are packed too tightly or stacked on top of one another, the water and detergent simply can’t reach all surfaces.
Correct loading is key to spotless results. Heavier items like pots, pans, large bowls and dinner plates should always go in the bottom rack. Reserve the top rack for smaller items such as mugs, glasses, small bowls and cups. If your dishwasher doesn’t have a third-level cutlery tray and you’re using a cutlery basket instead, make sure utensils are placed handles down to allow better cleaning.
Also, check that the spray arms (or spray jets) can spin freely and aren’t blocked by tall items — otherwise, water flow won’t reach every corner of the dishwasher.
Using the wrong wash cycle
Another common reason your dishwasher might not be cleaning dishes properly is using the wrong wash cycle. Many people opt for quick or eco cycles to save time and energy, but these shorter programmes aren’t always strong enough to tackle heavy dirt or dried-on food. Quick cycles are best for lightly soiled dishes — things like mugs or plates with just crumbs. But if you’re washing greasy pans or plates with dried-on food, you’ll need a hotter, longer cycle. These higher temperatures activate the detergent more effectively and help break down stubborn grease and food residue. Always match the wash cycle to how dirty your dishes actually are — it can make a huge difference in cleaning results.
Not using dishwasher salt
If your dishes come out of the dishwasher looking clean but covered in a white, chalky residue, the issue is likely hard water. This build-up is a common sign that limescale is forming inside your machine — and it usually means you’re low on dishwasher salt. Dishwasher salt softens the water, helping to prevent limescale from building up on your dishes and inside the appliance. If you haven’t topped it up in a while, this could be the root of the problem.
To keep your dishwasher working efficiently and your dishes spotless, remember to refill the salt compartment roughly every 4 to 6 weeks, depending on usage and local water hardness.
Not using rinse aid
If you’re noticing streaks or water marks on your glasses and plates, the problem could be a lack of rinse aid. This product helps water run off dishes more effectively, which not only leaves them shiny, but also helps them dry faster. Most modern dishwashers will alert you when the rinse aid compartment is empty, but if you have an older model, it’s a good idea to check and top it up regularly.
Using rinse aid isn’t essential for cleaning performance, but it can make a big difference to how your dishes look and feel once they’ve dried — especially glassware.
Low-quality dishwasher detergent
If your dishwasher isn’t cleaning dishes properly, the detergent you’re using could be to blame. Cheap or low-quality dishwasher tablets and powders often struggle to remove tough stains and greasy residue.
For the best results, stick to trusted brands and products recommended by your dishwasher manufacturer. Investing in a good-quality dishwasher tablet and rinse aid can make a noticeable difference in how clean and shiny your dishes come out.
Clogged dishwasher filter
One of the most common reasons for dishes coming out dirty is a clogged dishwasher filter. Food particles and grease can build up over time, stopping your dishwasher from draining properly and reducing its cleaning power. To fix this, check the filter — you’ll find it at the bottom of the dishwasher. Unscrew or lift it out (depending on your model), remove any food debris, and rinse it thoroughly under running water. To keep your dishwasher performing at its best, it’s a good idea to clean the filter regularly — ideally once a week if you use the machine daily. You should also give the entire dishwasher a deep clean at least once a month. You can use a commercial dishwasher cleaner, or opt for home remedies like bicarbonate of soda, white vinegar, or citric acid for a natural alternative.
Still not cleaning properly? Faulty parts could be to blame
If you’ve ruled out all the usual causes, your dishwasher may be struggling to clean properly due to a faulty component. When one part isn’t working as it should, it can affect water flow, temperature, or detergent distribution — all of which are key to getting spotless results.
Here are the most common dishwasher parts that could be responsible for poor cleaning performance.
Faulty inlet valve (water valve)
If your dishwasher isn’t cleaning dishes properly, a faulty inlet valve could be the cause. This part controls how much water flows into the dishwasher during a cycle. If it’s blocked or malfunctioning, the appliance may not get enough water to clean the dishes effectively.
Broken detergent dispenser
Another possible issue is a faulty detergent dispenser. If the lid doesn’t open properly or the microswitch inside fails, the dishwasher might not release the tablet or detergent at the right time — or at all. This can significantly reduce cleaning performance, leaving your dishes greasy or still dirty at the end of the cycle.
Clogged spray arms
Sometimes, food particles can get lodged inside the upper or lower spray arms, disrupting the water pressure and spray pattern. When this happens, the spray arms can’t distribute water evenly, and your dishes may come out dirty or still greasy.
Check the spray arms carefully — if the holes are blocked with food debris or limescale, rinse them under running water or use a small brush to clear the nozzles. Regular cleaning helps maintain strong water flow and improves overall cleaning performance.
Faulty circulation pump
Another possible reason your dishwasher isn’t cleaning properly is a faulty circulation pump. This component uses a motor and impeller to push water through the spray arms. If the pump is damaged or not working, water won’t be distributed correctly, and the cleaning cycle becomes ineffective. A broken pump usually requires professional repair or replacement, especially if your dishwasher makes unusual noises or doesn’t spray water at all during the wash cycle.
Faulty or burnt-out heating element
If your dishwasher isn’t cleaning dishes properly, it might be due to a faulty or burnt-out heating element. This component is responsible for heating the water during the wash cycle. When the water stays cold, detergents won’t dissolve fully, and tough food residue won’t be removed effectively.
If your dishes feel cold straight after the cycle ends — or you notice greasy marks — the heating element could be the cause and may need replacing.
Malfunctioning water diverter
Some dishwashers are equipped with a water diverter motor, which directs the water flow to different spray arms — usually switching between the upper and lower racks.
If you’re finding that dishes in the lower rack aren’t coming out clean, the diverter could be blocked or malfunctioning. A clogged diverter can sometimes be cleared by running a dishwasher cleaning cycle or using a descaling product. If that doesn’t help, the part may need to be inspected or replaced.
Dishwasher not cleaning properly – when to call a professional?
If your Bosch or Beko dishwasher isn’t cleaning properly and you’ve already ruled out maintenance or user errors, it might be time to call in a qualified appliance repair technician. A good engineer can quickly diagnose whether a faulty part is causing the issue and recommend the right fix — whether that’s a simple repair or replacing a worn-out component.
Summary: Why your dishwasher isn’t cleaning properly
- A dishwasher that’s not cleaning dishes properly can be caused by a number of things.
- Before calling in a technician, make sure the problem isn’t related to how you’re using or maintaining the appliance. One of the most common issues is overloading the dishwasher. When dishes are packed too tightly, water and detergent can’t reach every surface, leaving behind food residue or grease.
- Using the wrong wash cycle, especially one that’s too short or cool, can also result in dishes that don’t come out clean.
- Don’t forget the importance of rinse aid and dishwasher salt, especially in hard water areas. Poor-quality detergents can also impact results — switching to a trusted brand may help.
- Check the filter regularly for trapped food or debris, and give it a rinse under running water if needed. You should also clean your dishwasher once a month using either a specialist cleaner or natural alternatives like bicarbonate of soda, white vinegar, or citric acid.
- If you’ve checked all of the above and the problem persists, it could be a mechanical fault. Common culprits include the inlet valve, circulation pump, heating element, water diverter, detergent dispenser, or spray arms.
- In these cases, it’s best to contact a qualified appliance repair technician who can inspect the machine and carry out any necessary repairs.
Frequently Asked Questions – FAQ
How to make sure your dishwasher cleans dishes properly?
To get the best results from your dishwasher, always choose a wash cycle that matches how dirty your dishes are. Avoid using short or eco cycles for heavily soiled plates and pans. Loading the dishwasher properly is also key — make sure items aren’t too tightly packed so water can easily reach every surface. Don’t forget to use rinse aid and dishwasher salt, especially if you live in a hard water area. Check and clean the filter once a month, and run a monthly cleaning cycle using either a specialist cleaner or natural options like vinegar or baking soda. Lastly, stick to detergents recommended by your dishwasher’s manufacturer, as they’re designed to work best with your machine and remove even stubborn food residue.
Why is my dishwasher not cleaning properly and leaving residue?
If your dishwasher isn’t cleaning plates properly and is leaving a white or greasy residue, there could be several reasons behind it. Common causes include poor loading, choosing the wrong wash cycle, or using low-quality detergent. Not cleaning the machine regularly, failing to empty the filter, or skipping rinse aid and dishwasher salt can also lead to build-up and dull-looking dishes. If you’ve ruled out all of these maintenance issues, the problem might be a faulty component, such as a broken inlet valve, circulation pump, or heating element.
What to do if your dishwasher isn’t cleaning properly?
If you’ve already ruled out issues like poor maintenance or incorrect use, the problem may be due to a faulty part inside the dishwasher. In this case, it’s best to get in touch with a qualified appliance repair service. A technician can diagnose the issue and carry out any necessary repairs to get your dishwasher back to full working order.
How to make your dishwasher clean better?
If you want your dishwasher to clean more effectively, start by loading the dishes correctly, making sure they’re not too tightly packed and that the spray arms can move freely. Always choose a wash programme that matches how dirty your dishes are, especially for greasy pots or dried-on food. Use high-quality dishwasher tablets and rinse aid, ideally those recommended by your dishwasher’s manufacturer. Don’t forget to clean the filter regularly, as food debris can easily build up and reduce cleaning performance. It’s also a good idea to deep clean the dishwasher once a month using a specialist cleaner or natural methods. Lastly, keep the salt compartment topped up, especially if you live in a hard water area — it helps prevent limescale and boosts overall cleaning results.