How often should you deep clean your dishwasher?

Grease and limescale clog jets and leave dishes dirty.

A filter full of food scraps lets that waste end up back on the dishes, so they come out gritty and you rewash them by hand, which defeats the point of the appliance. Food left in the filter and on the door rim also causes smells, and Which? notes that food stuck on the rim can perish the door seals.

1. Remove and wash the filter. Bottom centre, usually a twist to release. Rinse under a hot tap and scrub with a soft brush. Bosch and Which? both suggest doing this monthly, and CHOICE suggests weekly, so it is the step to do most often.
2. Clear the spray arm jets. Lift the arms off, which usually unclip or unscrew, and clear any blocked holes with a cocktail stick or toothpick rather than sharp metal, which can damage them. Rinse them through.
3. Wipe the door seal and the door edge. Use a soft damp cloth on the folds of the seal and along the bottom lip of the door, which the wash does not reach.
4. Check the drain area. Remove any glass, labels or debris from the sump below the filter.
5. Run a hot cycle with a cleaner. Run the hottest programme with the machine empty and a dishwasher cleaner, or the machine care programme if yours has one. Manufacturers differ on white vinegar: Whirlpool suggests two cups in a glass measuring cup on the lower rack, while Which? advises against it and CHOICE notes that Miele does too, so check your manual first.
6. Descale if you are in a hard water area. A descaling product or citric acid on a hot empty cycle removes limescale. Follow the product instructions and your manual.
7. Check the salt and rinse aid. On machines with a softener compartment, top up the salt when the indicator asks. Salt softens the water and stops limescale building up in the first place.

• Dishes coming out with grit or food residue on them
• Streaks or a film on glassware, which often points to hard water or an empty rinse aid dispenser
• A stale smell when you open the door
• Standing water left in the bottom after a cycle, which can mean the filter or drain is blocked

• Never removing the filter
• Rinsing dishes under the tap before loading. ENERGY STAR says to scrape food off instead, since rinsing adds to the water and energy used, and CHOICE notes that rinsed plates can make a sensor-controlled machine wash less thoroughly
• Using bleach or harsh cleaners inside the machine, which Which? warns can degrade the seals and components. Never mix bleach with vinegar or any other cleaner
• Overloading so the spray arms cannot rotate freely
• Ignoring the salt reservoir in hard water areas

• Hard water areas need descaling more often
• Heavy daily use fills the filter faster, so check it more often
• Machines that mostly run eco programmes need an occasional hot cycle, since Which? notes that food residue builds up more on those cooler programmes

Standing water that persists after clearing the filter and checking the drain hose points to a pump or waste connection problem. Leaks from the door seal or the base need a technician.