Dishwasher Not Cleaning Properly What to Check in Abingdon

Published September 2026 | Dishwasher Not Cleaning Properly

This guide walks you through the most common reasons a dishwasher stops cleaning properly and what you can do to fix it yourself. It's aimed at homeowners in Abingdon and across Oxfordshire who want to diagnose the problem before deciding whether to call an engineer.

Before You Start - Safety First

Working on a dishwasher involves water and electricity in the same appliance, so it's worth taking a moment before you dive in. The checks in this guide are all low-risk, but a few basic precautions will keep you safe and protect your machine.

• Switch the dishwasher off at the wall and unplug it before inspecting any internal components.
• If your dishwasher is plumbed in permanently and has no plug, turn off the water supply at the isolation valve under the sink.
• Let the machine cool completely if it has just finished a cycle - the interior and heating element can stay hot for longer than you'd expect.
• Don't run a test cycle while your head or hands are inside the machine. This sounds obvious, but we've seen it happen.
• If you notice any burning smell, visible scorching on the control panel, or water collecting under the machine, stop and call a professional rather than continuing.

Most of the checks in this guide don't require any disassembly. You're looking, cleaning, and adjusting - not rewiring or replacing parts. Keep that scope in mind and you'll be fine.

What You Will Need

You won't need a toolbox for most of these checks. Here's what to have ready before you start:

• A soft brush or old toothbrush for cleaning filters and spray arm holes
• A bowl or tray to catch water when removing components
• White vinegar and bicarbonate of soda (for a cleaning cycle)
• A dishwasher cleaning tablet - brands like Finish or Fairy produce good ones, available in most supermarkets
• A torch or phone light for inspecting dark areas inside the drum
• Rinse aid and dishwasher salt if you haven't checked your levels recently
• A toothpick or thin wire for clearing blocked spray arm nozzles

Time estimate: allow 30 to 60 minutes to work through all the steps below. If the fix is something simple like a blocked filter or empty rinse aid, you could be back up and running in under 20 minutes.

Step-by-Step Instructions

Step 1: Check and Clean the Filter

The filter is the most common reason a dishwasher stops cleaning properly, and it's the first thing our engineers check when attending a job in Abingdon. Over time, food particles, grease, and limescale build up in the filter and restrict water flow. When that happens, dirty water effectively recirculates around your dishes rather than draining away cleanly.

To access the filter, remove the lower basket and look at the base of the drum. You'll see a cylindrical mesh filter and a flat coarse filter underneath it. Twist the cylindrical part anticlockwise and lift both pieces out. Hold them under a running tap and use a soft brush to scrub away any debris. If there's a heavy build-up, soak the filter in warm soapy water for ten minutes first. Once it's clean, reassemble and twist the cylindrical section back into place until it clicks.

Do this once a month as a routine and you'll prevent most cleaning problems before they start. Most brands - Bosch, Hotpoint, Beko, and others - use a similar two-part filter design, so this process is broadly the same across machines.

Step 2: Inspect the Spray Arms

The spray arms distribute water around the drum during a wash. If their nozzles are blocked with limescale or food debris, your dishes won't get the coverage they need. This is a particularly common issue in Oxfordshire, which sits in a hard water area - limescale builds up faster than many people realise.

Remove the lower spray arm by pulling it up or unscrewing the central nut (depending on your model). Most LG, Samsung, and Bosch machines have upper spray arms as well - check these too. Hold each arm up to the light and look through the nozzle holes. If they're partially blocked, use a toothpick or thin piece of wire to carefully clear them. Rinse the arm under the tap and spin it by hand to make sure it rotates freely before refitting. A spray arm that's stuck or sluggish in its rotation won't clean effectively even if the nozzles are clear.

Step 3: Check Your Water Temperature

Dishwashers need hot water to dissolve detergent properly and shift stubborn grease. Most machines should be running at 50 to 60 degrees Celsius on a normal cycle. If your boiler is set too low, or if the dishwasher is connected to a cold feed rather than the hot supply, cleaning performance drops noticeably.

Check your boiler thermostat and make sure the domestic hot water is set to at least 60 degrees. If you're unsure how your dishwasher is plumbed in, a quick look under the sink will show you whether the inlet hose connects to the hot or cold supply. Many machines - particularly budget Beko and Hotpoint models - heat water themselves regardless of the supply, but performance is always better when they're not starting from cold.

If your machine has an eco mode, try running a standard or intensive cycle instead. Eco modes use lower temperatures and less water, which works well for lightly soiled loads but often leaves residue on heavily soiled dishes.

Step 4: Load the Machine Correctly

This one isn't a mechanical fault, but it accounts for a surprising number of poor wash results we see across Oxfordshire. Overloading the dishwasher, nesting items together, or placing large pots in the lower basket in a way that blocks the spray arm rotation will all lead to patchy cleaning.

Cups and glasses go upside down in the top basket. Bowls should be angled downward so water runs off. Pots and pans in the lower basket should be positioned so they don't overlap or shield one another. Cutlery works best in a caddy with handles down, except for knives which should always go handle-up for safety. Don't place large cutting boards or serving plates flat along the sides - they act as a barrier and prevent water circulating.

It's also worth checking that nothing is jamming the spray arms. Give them a spin by hand after loading to confirm they rotate freely.

Step 5: Check Your Detergent, Rinse Aid, and Salt

Three things directly affect cleaning and drying quality: detergent, rinse aid, and dishwasher salt. If any of these run out or aren't topped up correctly, results suffer quickly.

Detergent tablets should go in the dispenser drawer, not loose in the drum. If the dispenser isn't opening during the cycle (you'll often find an intact tablet rattling around in the drum after washing), the dispenser mechanism may be clogged or faulty. Rinse aid prevents water spotting and helps dishes dry - top it up when the indicator light comes on, and increase the dosage setting if you're in a hard water area. Salt softens the water supply to the machine and protects the internal softener unit - it goes in the dedicated salt reservoir in the base of the drum, not with the detergent.

Use the Voltrade GoFIX diagnostic tool if you're not sure which of these factors is most likely causing your specific symptoms - it asks a series of targeted questions and helps narrow down the cause before you commit to a repair.

Step 6: Run a Maintenance Clean

If your filter and spray arms are clean but the machine still isn't performing well, it may need a deep clean to remove grease and limescale from internal components you can't easily reach. Place a dishwasher cleaning tablet in the drum (not the dispenser) and run a hot cycle with the machine empty. Alternatively, pour 250ml of white vinegar into a bowl on the upper rack and run a full hot cycle - this helps break down limescale.

Follow up with a bicarbonate of soda scatter across the base of the drum and run a short hot cycle. This combination is particularly useful in Abingdon and the surrounding area where hard water accelerates limescale accumulation. Aim to run a maintenance clean every one to three months depending on how heavily you use the machine.

Step 7: Check the Door Seal and Water Pressure

If the door seal is damaged or caked in debris, small amounts of water can escape during the wash, reducing the pressure inside the drum. Run your finger around the rubber door gasket and look for cracks, tears, or sections where food and mould have built up. Clean the seal thoroughly with a damp cloth and check the alignment of the door when it closes.

Low water pressure from your household supply can also affect cleaning. If other appliances in your Abingdon home are running at the same time - a washing machine or a shower - the pressure available to the dishwasher drops. Try running the dishwasher when no other water-intensive appliances are in use and see if results improve.

What to Do If This Does Not Fix It

If you've worked through all seven steps and your dishwasher is still leaving dishes dirty, the problem is likely internal and will need a diagnosis. Common culprits at this stage include a faulty circulation pump (the pump that drives water through the spray arms), a failing wash motor, or a blocked water inlet valve.

A failing circulation pump typically produces a humming noise during the wash cycle but poor spray pressure. A blocked inlet valve means the machine isn't filling with enough water to clean effectively - you can sometimes hear this as a shorter-than-normal fill time followed by poor results. These aren't DIY repairs on most machines, but they're typically fixable without replacing the appliance.

Run a diagnostic cycle if your machine supports it. Bosch and Siemens machines often have a hidden diagnostic mode activated by pressing a combination of buttons at startup - check your manual for the specific sequence. This can generate a fault code that significantly speeds up an engineer's diagnosis.

When to Stop and Call a Professional

There are clear situations where you should put down the toothbrush and call an engineer. Our team in Abingdon sees these regularly:

• The machine is making a loud grinding or burning noise during the wash cycle
• There's standing water in the drum after the cycle finishes (this suggests a drain pump failure)
• The control panel is unresponsive or displaying persistent fault codes you can't clear
• The machine trips your consumer unit (fuse box) when it runs
• You can see water pooling under the appliance or signs of a leak at the back

A professional call-out in Oxfordshire typically costs between 60 and 90 pounds for the visit and diagnosis. Repair costs vary widely depending on the fault - a replacement pump or motor typically adds 80 to 180 pounds in parts and labour. If your machine is more than eight to ten years old and the repair cost approaches 250 pounds or more, it's usually worth considering a replacement rather than repairing.

Mid-range integrated dishwashers from brands like Bosch, Samsung, and LG typically start around 350 to 550 pounds installed. Entry-level freestanding machines from Hotpoint or Beko can be had for 250 to 350 pounds. Factor in installation if your old machine was integrated - this typically adds 60 to 100 pounds.

Questions About This Process

How often should I clean my dishwasher filter?

For a household that runs the dishwasher daily, cleaning the filter once a week is a good habit. If you use the machine every few days, monthly cleaning is typically enough. Homes in hard water areas like Abingdon and the wider Oxfordshire region should also descale more frequently - a monthly maintenance wash cycle helps prevent limescale binding debris to the filter mesh and internal components.

Why are my dishes cloudy even after a full wash cycle?

Cloudy or filmy dishes are most commonly caused by hard water limescale, low rinse aid levels, or water temperature that's too low to rinse detergent residue away properly. Check your rinse aid reservoir and increase the dosage setting if needed. If the cloudiness is on glassware specifically and doesn't wipe off, it may be permanent etching caused by using too much detergent over a long period - unfortunately this can't be reversed.

Is it worth repairing a dishwasher that's more than five years old?

It depends on the fault and the brand. A five-year-old Bosch or Samsung with a blocked pump or faulty spray arm is typically well worth repairing - these machines are built to last ten to fifteen years with reasonable maintenance. A budget machine where the total repair cost approaches 60 percent of the replacement price is harder to justify. Our engineers can usually give you a clear recommendation after diagnosis, and the Voltrade GoFIX tool can help you weigh up the options before you book.