Indesit dishwasher leaving white residue on glasses

This thread was marked as solved. Here's a summary of the problem and the fix, generated from the discussion below.

Indesit DFG15B1 leaving chalky white film on glasses and plastics

The problem

An Indesit DFG15B1 dishwasher was leaving a chalky white residue on glasses and plastic items. The machine was being used in a hard water area with Finish tablets and rinse aid. The spray arms and filter had already been cleaned.

Likely cause

The strongest diagnosis in the discussion is hard-water mineral deposit rather than a major fault. The accepted reply says all-in-one tablets may not provide enough softening in a hard water area, so an empty salt reservoir or an incorrect water-hardness setting is a likely cause. A softener unit fault was mentioned only as a possibility if the problem continued after those checks.

What fixed it

The accepted advice was to confirm the residue is limescale by seeing whether it wipes off with white vinegar, then fill the dishwasher salt reservoir and check that the machine’s water-hardness/softener setting matches the local supply. It was also suggested to avoid overdoing detergent, try a hotter full wash, and reduce rinse aid by one step as a test. If heavy deposits continued after salt was refilled and settings were corrected, further diagnosis should be carried out by a suitably qualified appliance engineer.

Checks to try

• Spray arms cleaned
• Filter cleaned
• Check whether the white film wipes off with white vinegar
• Check the dishwasher salt reservoir is filled
• Check the water hardness setting
• Try a hotter full wash
• Reduce rinse aid by one step as a test

Parts or tools mentioned

• Dishwasher salt
• White vinegar
• Rinse aid
• Finish tablets