Dishwasher salt is regeneration salt of the appropriate grain size for the built-in water softener in certain machines, not table salt to sprinkle into the tub. It is used only when the dishwasher has a dedicated reservoir and the manual calls for it, commonly in hard-water areas. Some markets and dishwasher designs do not use this system.
First check whether your dishwasher has a salt reservoir
There is often a large cap in the tub floor, but not every model has one. Check the manual and do not confuse the salt reservoir with detergent or rinse-aid dispensers.
Salt regenerates the built-in softening system
The softener exchanges hardness minerals from the water to reduce deposits; salt regenerates the exchange medium. It does not work as a direct dish cleaner and does not replace detergent.
Use dishwasher salt, not table salt
Fine table salt, iodized salt, or salt with anti-caking additives may be unsuitable for the reservoir and can contribute to blockage or residue. Use the type specified by the manufacturer and fill without forcing the cap or spilling large amounts into the tub.
Set the system for actual water hardness
Many dishwashers allow a hardness setting that controls regeneration. Use your water supplier’s data or a reliable measurement and set the machine according to the manual; an incorrect setting can waste salt or leave deposits.