White residue on dishes after the dishwasher: causes and what to do

Likely causes

• the salt reservoir is empty — Electrolux notes that without salt the water stays hard and leaves residue;
• the rinse aid has run out or is not being used — it helps dishes dry without marks;
• the water hardness setting is wrong: set too low, limescale remains; set too high, the water becomes too soft and glass turns cloudy;
• salt was spilt into the tub while refilling, or the reservoir cap is not screwed on tightly;
• table, sea or kosher salt was used instead of dishwasher salt — Bosch warns it can raise water hardness and damage the appliance;
• a harsh detergent or a programme that is too hot for glass — Electrolux lists these among the causes of tarnishing;
• a faulty water softener, salt sensor or rinse aid dispenser.

Safe steps you can try

1. Work out what the residue is: rub it with a finger — salt wipes off easily; limescale is hard to remove but comes off with vinegar (as Electrolux suggests).
2. Check the salt: if the indicator is on, refill it. Unscrew the reservoir cap at the bottom of the tub and pour the salt in through the funnel until it is full. On first use, Bosch advises filling the reservoir to the top with water first.
3. Screw the cap on tightly, wipe up any spilt salt and run a short cycle with no dishes to rinse away leftover salt — as Electrolux advises.
4. Use only dishwasher salt — not table, sea or kosher salt (Bosch).
5. Fill the rinse aid and use it in every cycle — Bosch advises adding it even if your tablets contain it.
6. Check your water hardness with a test strip (Bosch) and set the hardness level on the machine as your model's manual says.
7. Every two months or every 60 cycles, run a programme with a dishwasher cleaner — as Electrolux advises. If your machine has a care programme (Machine Care), use it.
8. Wash glass below 55 °C or on a glass programme, open the door as soon as the cycle ends and wash crystal by hand — these are Electrolux's tips against tarnishing.

When to call a technician

Call a technician if salt and rinse aid are filled and the hardness is set, but the residue stays; if the salt indicator stays on after refilling; if the salt is never used up or runs out very quickly; or if the rinse aid leaks or never goes down. The water softener, the salt sensor or the rinse aid dispenser is probably faulty.

A MasService technician will check them on site and name the price before starting the repair.

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