Dishwasher not cleaning properly: causes and safe checks

Usually simple

Quick answer

When dishes come out dirty, check whether the tablet dissolved. If it didn’t, an item may be blocking the detergent lid or spray arms. Clean blocked spray-arm nozzles and the filters, load so water reaches everything, and use a hotter programme for baked-on food. In hard water areas, top up salt and rinse aid.

Also covers: dishwasher leaving food on dishes · dishwasher leaving residue · dishes still dirty after wash.

Likely causes

What you can safely check yourself

Stop and call a qualified engineer if:
  • It still doesn’t heat after the checks. Heating faults need an engineer.
  • The code or problem comes back after you’ve done the safe checks on this page.
  • The next step would mean removing a cover or panel, or working on the pump, valves, heater, motor, door lock or wiring. That is a job for a qualified engineer.

Work through these in order. Stop as soon as one of the signs above applies.

Check the loading

  1. Make sure nothing stops the spray arms turning or blocks the detergent compartment lid.
  2. Leave space between items so water and heat reach every surface.
  3. Put heavily soiled pans in the lower basket, and cups and glasses in the upper basket.
  4. Scrape food off plates before loading.

Check the spray arms turn and aren’t blocked

Before you start
  • Switch off and unplug the appliance at the wall socket before you touch hoses, filters or the back of the machine. Make sure your hands and the plug area are dry.
  1. With the dishwasher switched off, turn each spray arm by hand. It should spin freely without hitting plates, pans or utensils.
  2. Look at the nozzle holes. Clear food or limescale with a cocktail stick or tweezers.
  3. If your manual shows how to remove the spray arms, rinse them through under the tap and refit them firmly.

Clean the dishwasher filters

Before you start
  • Switch off and unplug the appliance at the wall socket before you touch hoses, filters or the back of the machine. Make sure your hands and the plug area are dry.
  • Wear protective gloves. Broken glass and sharp debris can collect in the filter and pump area, and it is hard to see.
Dishwasher filter assembly Twist to unlock, lift out Coarse filter Flat fine filter sits flat in the base Wear gloves: glass collects here. Refit until it locks.
Dishwasher filter assembly. Positions vary by model — check your manual.
  1. Take out the lower basket.
  2. Twist and lift the filter unit out of the base of the tub, then separate the parts as your manual shows.
  3. Rinse every part under running water. Use a soft brush for stubborn debris and nothing abrasive.
  4. Wipe food remains out of the sump area around the filter opening.
  5. Refit the filters so they lie flat and lock in position. On many models arrows line up when they are locked.

Don’t run the dishwasher without the filters fitted.

Top up dishwasher salt and rinse aid

  1. If the salt indicator is on, fill the salt reservoir in the base of the tub with dishwasher salt and screw the cap back on firmly.
  2. Fill the rinse aid dispenser. Manufacturers recommend rinse aid even if your tablets contain it.
  3. Set the water hardness on the dishwasher to match your local water. Your manual explains how.

Never use table salt, sea salt or cooking salt in the reservoir.

Showing an error code?

These codes are related to this problem. Codes differ by brand, so pick yours:

Step-by-step guides

Related problems

Brand guides: AEG, Bosch, Miele, Samsung. More dishwasher problems and codes, or use the fault finder.

Sources

Last checked against these sources: .

We write every page in our own words from manufacturer guidance and check it against the sources above. If your manual says something different, follow your manual. How we check.