Dishwasher Not Cleaning Properly in Reading - What to Check First

Published August 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 before calling anyone out. It's aimed at homeowners in Reading and the wider Berkshire area who want to understand what's going wrong and work through it methodically.

Before you start - safety first

Before you touch anything inside your dishwasher, switch it off at the wall and unplug it. Don't just press pause or open the door mid-cycle - disconnect the power completely. If your dishwasher is hardwired with no visible plug, turn it off at the circuit breaker and tape over the switch so no one turns it back on while you're working.

Water and electricity are a dangerous combination, and even a machine that appears off can hold residual current in certain components. Once you've cut the power, wait a few minutes before reaching inside. The interior can stay warm for a while after a cycle, and any standing water left in the drum can be surprisingly hot. Our engineers at Voltrade regularly see minor scalds from people rushing these checks, so take a moment to be safe before you start poking around.

What you will need

You don't need specialist tools for most of these checks. A basic kit will get you through the majority of the diagnostic steps:

• A soft toothbrush or small cleaning brush
• A bowl or jug to scoop out standing water
• White vinegar (distilled, from any supermarket)
• A proprietary dishwasher cleaner such as Finish or Dettol
• A small flathead screwdriver
• A torch or phone light for checking dark corners
• Clean cloths or kitchen roll
• Rubber gloves

Set aside around 30 to 60 minutes for a thorough check and clean. If you're dealing with a particularly compacted filter or a spray arm that needs soaking, allow a bit longer. None of this requires technical knowledge - you just need to be methodical about it.

Step-by-step instructions

Step 1: Clean the filter

The filter is the single most common reason a dishwasher stops cleaning properly. Most modern machines - whether you have a Bosch, Hotpoint, Beko, or something else - have a cylindrical filter sitting at the bottom of the drum, usually beneath the lower spray arm. It catches food debris and grease during each cycle. When it gets clogged, water can't circulate through the machine effectively, and dishes come out greasy, gritty, or covered in food residue.

To clean it: remove the lower rack, locate the filter (it typically twists out anti-clockwise), pull it apart into its two components, and rinse both under a running tap. Use the toothbrush to scrub away grease or embedded food. Reinstall it firmly - a filter that's not seated properly will let debris back into the pump. Our engineers in Reading find that a blocked filter is responsible for roughly half of all "not cleaning" call-outs we attend. Aim to clean yours every four to six weeks.

Step 2: Inspect and clear the spray arms

Spray arms distribute hot water around the inside of the machine during a wash cycle. Most dishwashers have two - one under each rack - and some have a third at the very top of the drum. The small holes in these arms block up with mineral deposits and food particles over time, particularly in hard water areas like much of Berkshire, where limescale builds up faster than average.

Remove each spray arm (most clip or unscrew off), hold them up to the light, and check each hole is clear. Use a toothpick or a thin piece of wire to dislodge any blockages, then rinse the arm thoroughly under the tap. Reattach each one securely and check it spins freely. A spray arm that's loose, cracked, or not rotating will leave dishes in certain areas of the machine consistently dirty - often the back corners or items on the top rack.

Step 3: Check the water temperature

Dishwashers clean effectively at between 55 and 65 degrees Celsius. Below that range, grease doesn't break down properly and detergent doesn't activate as it should. You might notice a persistent greasy film on plates, a cloudy finish on glassware, or powdered detergent left undissolved in the dispenser drawer after a full cycle.

Run a complete wash and carefully check whether the machine feels warm to the touch from the outside mid-cycle. On machines with a display, confirm it's reaching the correct temperature. On older Hotpoint or Indesit models, the heating element can fail with age - it's a component that gets a lot of use. A failed heating element isn't a DIY repair; it's one for a qualified engineer.

Step 4: Examine the detergent dispenser

A dispenser that doesn't open during the wash cycle is a surprisingly common and easy-to-miss cause of poor cleaning. If the door is physically blocked by a utensil or pan handle sitting in the lower rack, or if the spring mechanism has failed or is gummed up, your dishes are sitting in hot water with no cleaning agent throughout the cycle.

After an empty test cycle, open the dispenser and check whether any detergent remains inside. If there's a solid block or powder left in there, the door didn't open properly. Check the latch mechanism for damage, limescale build-up, or anything physically obstructing it. Also make sure you're using the right product - tablets like Finish Quantum or Fairy Platinum All-in-One work reliably in most machines. Never use standard washing up liquid; the excessive foam it generates can damage the pump and leave a mess that takes several cycles to clear.

Step 5: Run a cleaning cycle

If your machine has a stale smell, visible discolouration inside the drum, or you haven't deep-cleaned it recently, a dedicated cleaning cycle is worth doing before anything else. Place a cup of distilled white vinegar in a bowl on the top rack and run a hot, empty cycle. This helps dissolve mineral deposits and clear residue from internal surfaces.

Alternatively, use a proprietary dishwasher cleaner - Finish Dishwasher Cleaner or a similar product is widely available in Reading supermarkets for around 3 to 6 pounds. These are formulated to break down grease and limescale in the parts you can't easily reach by hand, including the pump housing and internal pipework. In hard water areas across Berkshire, a monthly cleaning cycle makes a meaningful difference to both wash results and the long-term lifespan of your machine.

Step 6: Reconsider how you're loading the machine

Incorrect loading causes more "not cleaning" problems than most people expect. Dishes that overlap, face the wrong direction, or sit too close together will consistently come out with food still on them - not because the machine is faulty, but because water simply can't reach those surfaces.

The general principles: face everything towards the spray arm, load larger items around the outer edges, and make sure nothing is blocking the arms from spinning. Glasses and cups go on the top rack, opening facing downward. Pots and pans go on the bottom, angled so water drains off rather than pooling inside them. If you have a Samsung or LG dishwasher with adjustable or fold-down tines, use them - those features exist specifically to improve wash coverage for awkward items.

Step 7: Check the water supply

Your dishwasher needs adequate water pressure and volume to fill properly. If the inlet valve is partially blocked, the supply hose is kinked, or the stopcock under the sink isn't fully open, the machine may not be filling with enough water to clean effectively.

Pull the machine out slightly and inspect the hose at the back - look for kinks, tight bends, or any compression where the hose passes through a cabinet base. Make sure the stopcock is fully open. The water inlet filter (a small mesh screen where the supply hose connects to the machine) can also become clogged with debris over time. This is usually accessible with a screwdriver and clears with a gentle rinse under the tap. If you've noticed generally low water pressure elsewhere in the house, that's a plumbing issue rather than an appliance fault.

What to do if this does not fix it

If you've worked through all seven steps and the machine is still producing poor results, it's time to run a proper diagnostic rather than guessing. Voltrade's GoFIX tool lets you input your machine's symptoms and get a clearer read on likely fault codes - it's a useful way to narrow down whether you're looking at a pump issue, a sensor fault, or a control board problem before committing to a call-out fee.

It's also worth checking whether your machine is still under warranty. Most new dishwashers sold in the UK come with a minimum one-year manufacturer's guarantee, and some brands like Bosch and Samsung offer extended cover on certain ranges. If your machine is within warranty, contact the manufacturer before paying for an independent repair - you may be entitled to a free fix.

If the machine is eight to ten years old and you're dealing with multiple faults at once, do a basic cost-benefit check. A decent mid-range dishwasher in the UK currently costs between 300 and 600 pounds depending on brand and specification. If a repair quote is coming in at more than half the cost of a replacement, a new machine often makes more sense.

When to stop and call a professional

Some faults are genuinely not DIY territory, and pushing ahead on those can cause secondary damage that costs more to put right. Call a professional if:

• Your dishwasher is displaying error codes you can't clear with a reset
• There's water pooling on the floor after a cycle, which suggests a door seal failure or pump fault
• The machine makes loud grinding, buzzing, or humming noises during operation
• The heating element has failed and dishes consistently come out cold and wet rather than dry
• The control board or timer appears to be behaving erratically

Appliance repair in Reading typically costs between 60 and 120 pounds for a call-out and initial labour, with parts charged on top. For common faults like a spray arm replacement or a blocked pump, expect a total bill of around 80 to 150 pounds. Heating element replacements and control board faults tend to sit at the higher end, commonly between 120 and 220 pounds all in. Voltrade connects homeowners across Berkshire with vetted, experienced appliance repair engineers who can give a clear diagnosis and a fixed quote before any work starts.

Questions about this process

Why are my dishes coming out with a white film on them even though the dishwasher looks clean?

A white film or cloudy residue on dishes and glassware is typically caused by hard water and limescale build-up during the wash cycle. This is particularly common in Berkshire, which sits within a hard water zone. Try topping up the rinse aid dispenser and checking the salt level in your machine's built-in water softener - both are often overlooked. Running a monthly descaling cycle using white vinegar or a dedicated dishwasher cleaner usually clears this up within a few washes. If the problem persists, your softener setting may need adjusting to match your local water hardness level.

How do I know if my dishwasher pump is failing?

A failing pump commonly shows up as poor water circulation throughout the drum, dishes that come out barely rinsed, standing water left in the bottom of the machine after the cycle finishes, or a loud humming or grinding noise during operation. Some machines will show a drain error or pump fault code on the display. If you're seeing any combination of these signs, DIY fixes are unlikely to resolve it. Pump replacement typically costs between 100 and 200 pounds including parts and labour when carried out by a qualified engineer, and it's a repair worth doing on a machine that's otherwise in good condition.

Is it worth repairing an older dishwasher or should I just replace it?

As a rough working rule, if the repair cost is less than 50 percent of what a comparable new machine would cost, repairing is typically worth it. For machines over ten years old that are developing multiple faults, replacement often makes more economic sense in the longer term. A reliable mid-range dishwasher from Bosch, Beko, or Hotpoint currently costs between 350 and 550 pounds in the UK. Our engineers can advise on whether a repair is viable after a diagnostic visit, so you're not committing to expensive parts before you know the full picture.