How to clean a dishwasher properly (so it cleans your dishes)

A dishwasher cleans your plates by spraying dirty water at them, so it stands to reason it needs cleaning itself now and then. A machine that's started leaving grit on the glasses, or smelling, usually wants a proper going-over rather than a repair. Here's how to do it, top to bottom.

The filter and sump

This is the big one. The filter in the base traps food, and left too long it clogs, which is when dishes come out dirty and the machine starts to smell. Twist it out, rinse it under the tap, and clear the sump underneath. Do this every week or two if the machine gets a lot of use. Full steps are in our guide on cleaning the dishwasher filter.

The spray arms

The arms that spin and spray get their little jets blocked by limescale and bits of food, and a blocked jet leaves a patch of dishes that never gets washed. Unclip the arms and poke the holes clear with a cocktail stick. Our guide on cleaning the spray arms shows how they come off.

The door and seal

Wipe round the rubber door seal and the edge of the door, where grease builds up out of the water's reach. It's a common home for smells.

Run a maintenance wash

Empty machine, hottest cycle, with a dishwasher cleaner or a cup of white vinegar in the base. Once a month keeps it fresh.

Keep the salt and rinse aid up

Hard water is hard on a dishwasher. Keeping the salt and rinse aid topped up stops limescale and helps everything run clean and dry.

When a clean isn't enough

Cleaned all of it and dishes still come out dirty, or there's water left in the bottom? Then it's past maintenance. A blocked or failed drain pump, a spray arm that isn't turning, or a heating fault can all be behind it, and that's a job for an engineer.

Book a dishwasher repair

If a proper clean hasn't sorted it, book a dishwasher repair or find your local dishwasher engineer.

Frequently asked questions

How do I clean my dishwasher?

Clean the filter and sump, unclog the spray arm jets, wipe the door seal, then run an empty hot cycle with dishwasher cleaner or white vinegar. Keep the salt and rinse aid topped up.

How often should I clean my dishwasher?

Rinse the filter every week or two, and run a hot maintenance wash once a month. That heads off most smells and poor-cleaning problems.

Why does my dishwasher smell even though I clean it?

Usually food trapped in the filter, sump or spray arms, or grease round the door seal. If it lingers after cleaning, the water may not be draining fully and is going stagnant.

It still won't clean after cleaning it. Why?

The fault's mechanical: a blocked or failed drain pump, a spray arm that isn't turning, or a heating problem. That needs an engineer to diagnose.