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Dishwasher salt: what is it and what does it do?

Find out how dishwasher salt can make your dishes go from streaky to sparkling.


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If you’ve noticed that your dishes aren’t coming out as clean as they used to, with plates strangely streaky and glasses going cloudy, it could be something to do with the level of salt in your dishwasher.

What is dishwasher salt?

The salt for your dishwasher is essentially course-grained sodium chloride – it helps to soften the hard water that’s tough on your dishes and prevents the dishwasher’s softener unit from clogging up.

Most modern dishwashers will have an indicator light to remind you, but if not, there will be a float indicator in the drawer. It might be hard to see though, so you may want to set a reminder in your calendar once a month to fill it up.

You can find dishwasher salt in most supermarkets. Don’t just go reaching for the regular table salt to top it up though, because that will corrode the pipes and get clogged, which will break the machine!

What does dishwasher salt do?

It prevents limescale from building up in your dishwasher’s filter, so it affects how clean your plates come out. If you find that your dishes are coming out ‘streaky’ or ‘gritty’ instead of sparkling clean, you might be running low on salt.

If you live in a hard water area (like most of southern England) it's important to check it and make sure you've not run out.

Do I live in a hard water area?

The rocks and geology of your local area will determine whether you have hard water or not. The limestone and chalk regions in the South and East of England mean more minerals get into the water as it passes through, which makes it ‘hard’.

You shouldn’t worry about drinking it, of course – it’s just as harmless as softer water – but due to its mineral content it can be harsher upon pipes and containers, and that’s why limescale can build up quicker than in other areas.

There’s no single nationwide water service provider, so if you want to find out exactly what the water is like in your area, simply search the web for ‘water quality in ____’, and you’ll find the right report for your home.

Where does the dishwasher salt go?

To top up the salt, first you’ll need to remove the bottom rack from your dishwasher. It might be on rollers, so you’ll have to lift it a little to get it to come out. Once it’s out of the way, have a look on the floor of the dishwasher for a cap that you can unscrew (it’s usually off to one side).

Remove the cap, making sure to put it somewhere safe, then pour in your salt until it’s full again. A funnel can help keep everything in the right place, but you should wipe up any salt that spills onto the floor of the dishwasher.

Screw the cap securely back into place, making sure it’s tightly sealed. If it comes loose during a washing cycle and detergent gets in there, it could break the machine, so make sure it’s on tight. Then you’re ready to put the bottom rack back into place and start filling it with that seemingly never-ending cycle of dirty dishes.

How much salt should you put in a dishwasher?

When it comes to adding salt to your dishwasher, the recommended amount can vary based on the manufacturer. Typically, you’re looking at about a cup or so of dishwasher salt, and you’ll usually want to fill the salt compartment until it’s full. Most dishwasher models have a special indicator light that tells you when it’s time to add more salt. If you’re unsure, check your dishwasher's manual.

Can you use anything instead of dishwasher salt?

No! Of course not. You might be tempted to use table salt or sea salt in your dishwasher, but it’s not a good idea. Dishwasher salt is specifically designed to soften water, which helps prevent limescale build-up. Other types of salt can be too coarse or contain additives that could damage your dishwasher. Some people try using baking soda or white vinegar as an alternative, but they don’t work as well for this purpose. Stick with dishwasher salt for the best results—it’s worth it for maintaining your machine and getting spotless dishes.

Is it safe to run a dishwasher without salt?

Running a dishwasher without salt can be a bad move, especially if you live in an area with hard water. Without salt, the dishwasher’s built-in water softener can’t do its job, leading to limescale build-up. This can make your dishes look cloudy and your machine less efficient over time. In the long run, it could even shorten the lifespan of your dishwasher. So, while it might be tempting to skip the salt, especially if you’ve run out, it’s best to keep that compartment topped up for the sake of your dishwasher and your dishes.

Any questions?

Looking for the best dishwasher? We’ve got a great range to choose from, including integrated dishwashers and slimline dishwashers. Check them out online, or pop in-store for a chat, and find the dishwasher that’s right for you.

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