How to use dishwasher salt

You need dishwasher salt to keep your machine working well. But what is dishwasher salt, how do you use it and why is it important? Our guide explains it all.

How to use dishwasher salt

Salt is an essential part of cooking, its sodium content really makes flavours pop, and can mean the difference between blandness and brilliance. Salt’s benefit extends far past the actual food preparation stage though, and all the way into dishwashing.

Keeping your dishwasher topped up with Finish Dishwashing Salt is necessary to ensure that your machine keeps working at optimum performance levels, and that your dishes come out looking like new. The idea of putting salt in an appliance might seem a little bit strange, so we’ve put together a list of facts about dishwasher salt to help you understand why it is so essential.


  1. Dishwasher salt is sodium chloride, the same chemical that makes up table and sea salts. You shouldn’t use table salt though as it is much finer and can block and cause damage to your dishwasher. Dishwasher salt granule size is larger and ensures the salt dissolves slower without blocking the softener unit.
  2. Dishwasher salt doesn’t actually enter the dishwasher instead it flows through the softener unit before being drained with the waste water.
  3. The way that dishwasher salt works is by providing sodium for the dishwasher’s ‘ion exchange resins’ that are in the softener. When regenerated by the sodium, these work to attract and trap the magnesium and calcium ions that cause hard water.
  4. Dishwasher salt has much larger granules than regular salt in order to help them dissolve without a risk of creating a blockage which would result in malfunctioned softener unit. For finer salt the risk is real!


Prevents Limescale

Topping up dishwasher salt can lead to less limescale building up in your machine as it softens the water as it flows into the cleaning chamber. All in all, a better running machine also means there is less chance of other parts malfunctioning. You can ask your supplier for the hardness levels in your area and some can tell you through their website. It’s good to get into the habit of checking salt level regularly (i.e. once a month) and making sure that salt tank/reservoir is always filled.

No more spots and watermarks

Spots and watermarks can become a constant problem without the use of Finish Dishwasher Salt. These marks can occur when the water is hard, causing detergent to perform less effectively. Since dishwasher salt effectively softens water, these heavy deposits of limescale will not accumulate in your dishwasher, and will help keep your dishes looking cleaner.


Most machines have an indicator light that will go on when you switch your machine on to let you know its running low on dishwasher salt. If the light is not on, this usually means that your machine has enough salt to wash another load of dishes.

In terms of working out how much dishwasher salt your machine needs, ensure you check the packaging to find out how much salt you will need. It may help to use a measuring cup and a funnel to both measure out and supply the salt to your dishwasher. We recommend leaving the salt level approximately 1cm under the lip of where the cap will screw back on so you don’t overfill your machine and potentially waste your product.

Where should I put dishwasher salt?

It’s easiest to top up with dishwasher salt simply when your machine is empty, so after unpacking a clean load of dishes is the most suitable time. Top up your dishwasher salt by locating the softener unit, which is usually at the bottom of the dishwasher by the drain, unscrewing the cap and simply pouring in the salt.


  • Unscrew the cap and fill with dishwashing salt. If the reservoir for the salt is full of water, you can still pour the salt in as it will displace what is in there. If you don’t plan to run the machine immediately after refilling, it’s recommended to wipe out displaced water from the machine with a paper towel. If you run the machine for the first time make sure to fill salt reservoir with a water - in order to regenerate softener unit salt have to be in a solution. Always follow the instructions from manual provided by the machine manufacturer.
  • Replace the cap, ensuring it is closed tightly and it should be ready to use again. Most water softeners will have an adjustable setting for water hardness, so make sure this is adjusted correctly to make sure that you get the perfect clean.

So now you understand the benefits and uses of dishwasher salt, remember to keep your dishwasher topped up. Refilling your dishwasher regularly will help to ensure that whatever your water hardness, your dishes come out clean and sparkling after every wash, and your machine is protected from limescale build-up.

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