Dishwasher Not Cleaning Properly - What to Check in Aldershot

Published September 2026 | Dishwasher Not Cleaning Properly What to Check

You open the dishwasher after a full cycle and the plates come out with last night's pasta still stuck to them, glasses look smeared, and the cutlery has dried food baked on that wasn't there before. It's frustrating, especially when you've come to rely on the machine every single day. Before you resign yourself to hand-washing or start pricing up replacements, there's a good chance the problem is something fixable - often without needing to call anyone out.

Understanding What Is Actually Happening Inside Your Dishwasher

A dishwasher cleans through a combination of hot water, detergent, and mechanical spray action. Water is drawn in, heated to a target temperature (usually between 50 and 65 degrees Celsius depending on the programme), and then pumped through rotating spray arms that blast water onto your dishes from below and above. The dirty water drains away, and the process repeats through the wash and rinse phases.

When cleaning results deteriorate, something in that chain has broken down. It could be mechanical - a blocked spray arm or failing pump - or it could be a maintenance issue that's built up gradually over time. It could also be something as simple as how the machine is being loaded. Our engineers at Voltrade use the GoFIX diagnostic tool to run through each element of that chain systematically, because the symptom (dirty dishes) can have half a dozen different root causes, and chasing the wrong one wastes time and money.

The good news is that in a large proportion of cases we attend in the Aldershot area, the problem turns out to be a maintenance issue rather than a component failure. That means you may be able to sort it yourself this weekend.

The Most Common Causes of a Dishwasher Not Cleaning Properly

Blocked or Damaged Spray Arms

The spray arms are the rotating plastic components that distribute water across your dishes. They have small holes (jets) along their length, and those jets block up with mineral deposits, food debris, and grease over time - particularly in Hampshire, where hard water is common across much of the county.

When jets are partially or fully blocked, water pressure is uneven and some parts of the wash load simply don't get enough coverage. The lower spray arm is typically the worst affected because it sits closest to the food particles that collect at the bottom of the machine. Remove the spray arms (they usually unclip or unscrew counter-clockwise) and hold them up to the light - you should be able to see through every hole clearly. Use a cocktail stick or thin wire to clear any blockages, then rinse them under a running tap. Also check the arms spin freely when you replace them - if they're cracked or warped, replacement arms for brands like Bosch, Hotpoint and Beko typically cost between 15 and 35 pounds.

A Clogged Filter

This is the number one cause we find in Aldershot homes where the dishwasher has gradually stopped cleaning well over several months. The filter assembly sits at the base of the machine and catches food particles so they don't recirculate onto your dishes. When it's clogged, dirty water can't drain properly, and the wash water itself becomes contaminated.

Most dishwashers have a cylindrical fine filter that twists out and a flat coarse filter underneath it. Pull both out, rinse them under warm water and scrub gently with an old toothbrush and some washing-up liquid. If the filter hasn't been cleaned in a long time, soak it in warm soapy water for 20 minutes first. Do this monthly going forward - it takes five minutes and makes a significant difference to wash quality.

Water Temperature Too Low

Dishwashers need hot water to activate detergent enzymes and to shift grease effectively. If the heating element has failed or is struggling, the machine may complete its cycle at a temperature that's too low to clean properly. You might also notice that dishes take much longer than usual to dry, or don't dry at all, since both cleaning and drying rely on adequate heat.

A failed heating element is a job for a professional. It typically sits at the base of the machine and involves draining the unit and working with electrical components. Don't attempt this one yourself unless you have appliance repair experience.

Overloading or Incorrect Loading

This is the cause homeowners are least willing to admit, but it's common. If dishes are stacked too close together, or large items block the spray arms from rotating, whole sections of your load won't get cleaned regardless of how well everything else is working. Bowls nested inside each other, glasses laid horizontally, or a large chopping board lying flat across the bottom rack are all common culprits.

Check the rotation of both spray arms before you run a cycle. Give each one a spin by hand - if it hits something in your loaded machine, rearrange until it moves freely. Tall items like baking trays belong on the sides or back, never blocking the central area. Pots and pans should face inward and downward.

Low Salt or Rinse Aid

In hard water areas like much of Hampshire, dishwasher salt is essential. It regenerates the internal water softener, which prevents limescale building up on the heating element, spray arms, and inside the machine generally. Without it, limescale progressively reduces cleaning performance and eventually causes component damage.

Rinse aid helps water sheet off dishes during the final rinse, preventing spots and smearing. If you're seeing cloudy glasses or white streaks on cutlery, this is usually the first thing to check. Both the salt and rinse aid indicators on the door panel will usually tell you when levels are low, but the sensors aren't always reliable - get into the habit of checking both manually every few weeks.

Detergent Problems

Using the wrong amount, the wrong type, or detergent that's absorbed moisture from the air and clumped together can all affect wash quality. All-in-one tabs are convenient but can underperform in short eco cycles that don't get hot enough to dissolve them fully. If you're running quick or eco programmes frequently, consider switching to a powder or gel detergent that dissolves faster. Also check the detergent drawer isn't blocked with residue preventing the door from opening at the right point in the cycle.

Solutions That Actually Work

Before calling anyone out, work through these steps in order. Many Aldershot residents who contact us end up resolving the issue themselves using this sequence.

1. Clean the filter assembly thoroughly - remove both sections and scrub under running water.
2. Remove and clear the spray arms - check every jet is open and the arms spin freely.
3. Top up the salt dispenser (located under a cap on the floor of the machine, usually on the left side) and the rinse aid dispenser (usually inside the door).
4. Run a hot maintenance wash - load nothing and run the machine empty on its hottest programme (typically 70 degrees or the "intensive" setting) with a dishwasher cleaner like Finish or Dalgety placed in the drum. This breaks down grease and limescale from internal components.
5. Check the detergent drawer opens freely and isn't clogged. Clean it out and use a fresh detergent tab in the next cycle.
6. Reload your dishes following the manufacturer's guidance for your specific model - Bosch, Samsung, and LG all publish loading guides on their websites.

If you've done all of the above and wash results haven't improved after two or three cycles, the problem is likely a component failure rather than a maintenance issue.

When You Need Professional Help Versus Sorting It Yourself

There's a clear dividing line here. Maintenance tasks - filter cleaning, spray arm clearing, salt and rinse aid, running a service wash - are all things any homeowner can do safely. These require no tools, no disassembly, and no technical knowledge.

Component repairs are a different matter. A failed heating element, a pump that isn't circulating water properly, a faulty wash motor, a broken door seal, or a control board issue all require disassembly of the machine and, in most cases, working with water connections or electrical components. Attempting these without experience risks making the problem worse, causing a water leak, or voiding any remaining warranty on your appliance.

Signs that you need a professional include:

• The machine completes its cycle but dishes are completely cold at the end
• You can hear the pump running but water doesn't seem to be reaching the dishes
• Water is pooling at the bottom after the cycle finishes
• Error codes are showing on the display
• The detergent drawer is opening but wash results haven't improved after full maintenance

Our engineers cover the whole of Aldershot and the surrounding Hampshire area and use the Voltrade GoFIX diagnostic system to pinpoint component failures quickly, which keeps labour time down and means you get an accurate repair estimate before any parts are ordered.

What to Expect from a Repair Visit

A standard diagnostic visit for a dishwasher that isn't cleaning properly typically takes between 45 minutes and an hour and a half, depending on what's found. Call-out and diagnostic fees in the Aldershot area commonly range between 60 and 90 pounds, with many engineers applying that cost against the repair if you proceed.

Common repairs and their typical cost ranges in 2026 pricing:

• Heating element replacement: 120 to 180 pounds including parts and labour
• Wash pump or circulation pump replacement: 150 to 250 pounds
• Control board replacement: 180 to 300 pounds (varies significantly by brand and model)
• Door seal replacement: 80 to 130 pounds
• Spray arm replacement: 40 to 70 pounds fitted

As a rough rule of thumb, if a repair is going to cost more than half the price of a new equivalent machine, replacement is worth considering. A basic dishwasher from brands like Beko or Hotpoint starts at around 250 to 350 pounds, while mid-range models from Bosch or Samsung sit at 450 to 650 pounds. An engineer can help you make that call once the fault is diagnosed.

When a technician visits your Aldershot home, they'll want access to the front of the machine and enough space to pull it forward from the housing. Clear the area underneath the counter if your dishwasher is built in, and have the model number ready - usually on a sticker inside the door frame. This speeds up parts identification if anything needs ordering.

Common Questions from Aldershot Homeowners

Why are my glasses coming out cloudy even though everything else seems clean?

Cloudy glasses are almost always caused by one of two things: low rinse aid, or limescale from hard water. Hampshire has some of the hardest water in the UK, which makes limescale build-up a real issue over time. Top up your rinse aid and use the correct level of dishwasher salt, then increase the water softener setting inside the machine if your model allows it. If cloudiness persists, the glasses themselves may have sustained etching damage from hot water and excess detergent - this is permanent and can't be reversed.

My dishwasher seems to be running fine but the bottom rack is not getting clean - what is going on?

The lower spray arm is responsible for cleaning the bottom rack, and it's the most prone to blockage because it sits closest to the food debris collecting in the base of the machine. Remove it, check every jet is clear, and make sure the arm spins freely once reinstalled. Also confirm the filter directly beneath it is clean - a clogged filter restricts water flow to the lower arm first. Overloading the bottom rack with large items that block rotation is another common cause specific to the lower level.

How often should I be running a maintenance wash on my dishwasher?

Once a month is a practical target for most Aldershot households using the machine daily. Run it empty on the hottest programme available with a specialist dishwasher cleaner in the drum. In addition to that monthly wash, clean the filter every two to four weeks and check salt and rinse aid levels weekly. If you're in a particularly hard water area, you may find you need to add salt more frequently than the indicator suggests. This level of maintenance significantly extends the working life of the machine.

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

If the machine is under seven years old and the repair cost comes in at less than half the price of a comparable new model, repair is usually the better value. Machines from Bosch, Siemens and Miele tend to have longer useful lifespans and better parts availability, making them more worth repairing at a later age. If the dishwasher is over ten years old and facing an expensive component failure like a motor or control board, replacement often makes more financial sense - especially given the improved energy and water efficiency of current models.