Dishwasher Not Cleaning Properly? Causes & Fixes

Switch off, unplug and close the water supply before dismantling the appliance

Dishwashers combine mains electricity, hot water and hidden pumps. Stop using the machine if it leaks, trips the electrics, smells burnt or contains sharp broken glass.

MOST LIKELY CAUSES

Start with these

Blocked spray arms Food and scale reduce jet pressure.

Dirty filters Restricted circulation leaves debris on dishes.

Poor loading Items may block spray-arm movement.

Low temperature or detergent issue Grease and residue remain when wash conditions are weak.

◫ Symptom variations Match the exact point in the wash cycle. ⌄

Food remains on dishes
Glasses look cloudy
Top rack cleans poorly
Detergent tablet remains
Spray arms do not rotate

✓ Quick checks Simple checks before removing panels. ⌄

Note the exact cycle stage when the fault appears.
Record any error code before switching off.
Check filters, spray arms, hoses and visible water connections.
Confirm the appliance is level and correctly loaded.
Unplug before touching filters, hoses or internal parts.

If the cause is external: correct the hose, filter, loading or supply fault and test carefully.

If electrical, pump or internal leaks are suspected: stop and call an appliance engineer.

1 Step 1 — Clean filters and spray arms Switch off and unplug before removing filters, hoses or panels. ⌄

Process

Remove debris and rinse all accessible parts.

Success looks like: Water circulation improves.

Escalate when: Persistent poor flow suggests a circulation fault.

2 Step 2 — Check loading and arm movement Switch off and unplug before removing filters, hoses or panels. ⌄

Process

Spin each arm by hand and rearrange tall items.

Success looks like: Jets can reach all racks.

Escalate when: If an arm binds or splits, replace it.

3 Step 3 — Check detergent and programme choice Switch off and unplug before removing filters, hoses or panels. ⌄

Process

Use suitable detergent and a cycle matched to the load.

Success looks like: Cleaning improves.

Escalate when: Poor results on all settings point to water or circulation problems.

⌁ Common causes explained Why dishwasher faults develop. ⌄

Poor cleaning is usually caused by blocked spray arms, dirty filters, incorrect loading, low water temperature, weak circulation or detergent and rinse-aid problems.

The stage of the cycle is the main clue. Fill faults happen at the start, circulation faults during washing, heater faults once the wash is underway, and pump faults during draining.

⌘ Advanced diagnostics Appliance-engineer checks and repair work. ⌄

Test circulation-pump performance.
Check water temperature and heater operation.
Inspect diverter valve.
Check water-level sensing.
Descale internal waterways.

▣ Parts that may need replacing Common components linked to this fault. ⌄

Spray arm
Filter assembly
Circulation pump
Diverter valve
Detergent dispenser

! When to call an appliance engineer Conditions that should end basic troubleshooting. ⌄

The dishwasher trips the electrics.
Water leaks from inside the cabinet.
The circulation or drain pump is grinding or seized.
Internal electrical testing is required.
The appliance must be dismantled to reach the fault.
The same fault returns after basic checks.

? Frequently asked questions Common dishwasher questions. ⌄

Why is there a small amount of water below the filter?

A small amount can be normal on some models. Standing dirty water above the filter usually indicates a drainage fault.

Why are plastics still wet after the cycle?

Plastic retains less heat than glass or ceramic, so some moisture is normal even when the drying system works.

Should I keep resetting the electrics if the dishwasher trips?

No. Unplug it and arrange electrical fault testing.