How to clean a dishwasher: filter, spray arms and seal

2 min read · 8 steps · Updated 3 October 2026

A dishwasher that leaves grit on glasses, smells, or stands in a puddle at the end of the cycle nearly always has a clogged filter. The filter catches food so it does not block the pump, and it needs cleaning by hand. Ten minutes every month or two keeps the machine washing properly.

Step by step

1. Switch off and empty

   Switch the dishwasher off and pull out the bottom rack, so you can reach the floor of the machine.

   Done

2. Take out the filter

   The filter is a round cylinder in the floor, usually under the lower spray arm. Twist it, in most models anti-clockwise, and lift it out. Many have a flat metal mesh plate underneath that lifts out as well.

   Done

3. Wash the filter

   Rinse it under warm running water. Scrub off grease and food with a soft brush or an old toothbrush and a little washing-up liquid. Do not use wire wool or harsh cleaners, which damage the fine mesh.

   Done

4. Clean the sump

   Wipe out the opening where the filter sits and remove bits of glass, labels, seeds or bones by hand. Take care: broken glass often collects here.

   Done

5. Refit the filter

   Put the mesh plate and the filter back and twist until it locks. A filter that is not locked lets debris into the pump.

   Done

6. Clear the spray arms

   Pull the lower spray arm up and off. The upper one unclips or unscrews under the top rack. Rinse them and poke each hole clear with a toothpick. Soak them in warm soapy water for 15 to 20 minutes if they are greasy. Refit them and spin each by hand to check that it turns freely.

   Done

7. Wipe the door seal and edges

   Wipe the rubber seal and the bottom edge of the door, which the water never reaches, with a cloth and warm soapy water. Dry it afterwards.

   Done

8. Run a hot cleaning cycle

   Put a cup of white vinegar upright on the top rack of the empty machine and run the hottest programme. A dishwasher cleaner from the shop does the same and also removes limescale. Leave the door ajar afterwards to let it dry.

   Done

Good to know

Clean the filter every one to three months, more often if you do not scrape plates, and run the hot cleaning cycle about once a month.

Keep the salt and rinse aid topped up if your machine has compartments for them. Without salt, hard water leaves a white film on glasses even with all-in-one tablets.

Running only short, cool programmes lets grease build up. Use a hot programme now and then.

Related: washing machine smells bad: how to clean it and how to unblock a sink.

In short: Bottom rack out, twist out the filter, wash it, clear the sump, refit and lock. Clear the spray arm holes, wipe the seal, run a hot empty cycle with vinegar or cleaner.