Quick Answer: Any coarse, pure dishwasher salt works. Brand matters less than grain size and purity. For a Bosch, Thermador, or Gaggenau, Bosch Finish SGZ9091UC is the co-branded salt sold for those machines. Miele owners can stick with Miele's own reactivation salt. If you're refilling often on very hard water, a bigger bag like IMPRESA's 4.4-lb coarse salt costs less per refill and does the same job. Never use table salt.
Disclosure: As an Amazon Associate, Grains & Gallons earns from qualifying purchases.
If you just moved into a house with a European-built dishwasher and found a mysterious screw cap on the floor of the tub, welcome. That's a salt reservoir. Your dishwasher has its own miniature water softener, a small bed of ion-exchange resin, and the salt is what recharges it. It's the same principle as a whole-house softener, shrunk down to fit under the lower rack.
When it runs out, you won't get a dramatic failure. You'll get cloudy glasses, a white film on dark plates, and scale slowly building up on the heating element. That's why people search for this, and it's why the details below matter more than which logo is on the box.
In this guide
- First, check that your machine actually takes salt
- What makes salt "dishwasher salt"
- Salts worth buying
- How the little softener inside your dishwasher works
- Set the hardness, or the salt is wasted
- Four mistakes that make people think the salt "doesn't work"
- Refilling without a mess
- When the problem isn't salt at all
First, check that your machine actually takes salt
Pull out the lower rack and look at the floor of the tub. A round screw cap, usually near the filter, means you have a salt reservoir. No cap means no softener, and salt does nothing for you. Don't put salt anywhere else in the machine.
Many Miele dishwashers have the reservoir, and so do certain models from Bosch-family brands (Bosch, Thermador, Gaggenau) and some other European makers. Many common US-market dishwashers don't. If you can't find the cap, check your manual for a "water softener" or "salt" section.
What makes salt "dishwasher salt"
It's all sodium chloride. The difference is everything else in the bag:
- Coarse grain. Big crystals dissolve slowly and evenly. Fine salt dissolves too fast, can cake, and can block the reservoir or the brine path. That's the main reason table salt is out, along with its anti-caking agents and, in iodized salt, the iodine.
- No additives. Some whole-house softener pellets are sold with cleaning or rust-control additives. Those additives were never meant for a dishwasher's tiny resin bed and short rinse cycle. Even plain softener pellets are usually too big for a narrow reservoir opening.
- Dry, free-flowing. Store the box sealed. Salt that has absorbed moisture clumps in the funnel.
That's how we chose the five below. All of them are sold specifically as dishwasher salt, all are coarse-grain, and they come from appliance brands or sellers whose listings say they're for built-in softener models. We looked at listing descriptions and owner reviews for complaints like clumping, dust, or fine grains, not lab tests of our own.
Salts worth buying
Bosch Finish SGZ9091UC Dishwasher Salt (2 kg)
Best for Bosch-family dishwashers · Check price on Amazon
Bosch and Finish co-brand this salt for Bosch-family dishwashers that have the reservoir. If you'd rather never wonder about compatibility or your warranty, this is the box. Two kilograms (about 4.4 lb) will cover several refills for most households.
Downside: You're paying a bit for the logo. The salt itself isn't magic, and any coarse pure dishwasher salt does the same job.
Miele Dishwasher Reactivation Salt (3.3 lb)
Best for Miele owners · Check price on Amazon
This is Miele's own branded salt, an extra-coarse grain made for Miele dishwashers. It's the straightforward choice if you have a Miele and want the salt from the same company as the machine. At 3.3 lb it's one of the smaller packs here, which is fine for soft-to-moderate water and a little annoying on very hard water.
Downside: The small box size means more frequent reorders if your hardness setting is high.
Finish Dishwasher Salt (4 kg)
Best larger box from a major brand · Check price on Amazon
This is the same Finish brand as the Bosch box, in a 4 kg (about 8.8 lb) size. The listing says it prevents limescale and white residue in hard water. It's a good middle ground if you want a big-name brand without reordering every couple of months.
Downside: Big boxes need dry storage. Keep it out of a damp utility room or the cabinet under the sink.
IMPRESA Dishwasher Salt, Coarse Grain (4.4 lb)
Best additive-free alternative · Check price on Amazon
IMPRESA sells a 2 kg bag of coarse-grain salt described as pure and additive-free, and the listing names Bosch, Miele, Whirlpool, and Thermador models as compatible. It's for people who don't care about the brand on the box but do care about grain size and purity, which are the two things that actually matter.
Downside: It's a third-party brand. If your dishwasher is still under warranty and you're cautious, keep your receipt and the bag label just in case.
Aromasong Dishwasher Salt (19 lb)
Best bulk buy for very hard water · Check price on Amazon
If your water tests at 15 gpg or higher, your dishwasher's softener will use salt quickly at its top setting, and small boxes get old fast. Aromasong sells a 19-lb bulk size, described as a natural water softening agent compatible with Bosch, Miele, Whirlpool, Thermador, and others. Pour some into a smaller, sealed container with a spout for day-to-day refills, and keep the rest closed tight.
Downside: Nineteen pounds is a lot of salt for anyone on moderate water. It can sit for a long time and absorb moisture. Only buy bulk if you're refilling often.
How the little softener inside your dishwasher works
Knowing this makes the rest of the article make sense. Incoming water passes through a small chamber of resin beads before it reaches the wash. The beads trade sodium for the calcium and magnesium in the water, so the wash water is soft. Eventually the beads fill up with hardness minerals. Then the dishwasher runs salt water (brine) from the reservoir back through the chamber, which knocks the calcium off and reloads the beads with sodium. The hardness gets flushed down the drain.
That has three practical consequences:
- The salt never touches your dishes. It stays in the softener loop. Your glasses won't taste salty if the cap is screwed on properly and you didn't spill.
- How fast salt is used depends on how hard your water is and how often you run loads. A household on 5 gpg water running a load a day will refill far less often than a family of five on 20 gpg running two loads.
- Running out isn't an emergency, but it adds up. Hard water reaches the wash until you refill, and you'll see the results on glassware within a few loads. Most machines have a salt warning light. Don't ignore it for weeks.
Set the hardness, or the salt is wasted
The salt only recharges the softener. How hard the softener works depends on the hardness setting you program into the dishwasher. If it's set too low, you'll get spotty glasses with a full reservoir. If it's set too high, salt disappears quickly for no reason.
- Test your tap water, or look up your utility's hardness report.
- Convert if needed: 1 grain per gallon (gpg) = 17.1 ppm (mg/L) of calcium carbonate. So 200 ppm is about 11.7 gpg. Our hardness units explainer has a full table, plus German degrees (°dH), which many European manuals use.
- Find the matching setting in your manual. Bosch-family machines typically use an H-scale, and Miele uses its own table. Enter it through the settings menu.
If you already have a whole-house softener, your dishwasher is getting soft water. Most manuals then tell you to set the softener to its lowest setting or turn it off, and you may not need salt at all. Our guide to adjusting a dishwasher after installing a softener walks through it.
Four mistakes that make people think the salt "doesn't work"
- Filling a dry reservoir without water the first time. Many manuals tell you to add water to the reservoir before the very first salt fill. After that it stays full of water, and you only add salt.
- Spilling salt and not running a cycle. Salt grains left in the tub are corrosive to stainless parts. Wipe up spills and run a rinse or a normal load right after refilling.
- Counting on "salt function" tablets. Multi-function tablets that claim to replace salt don't recharge a resin bed the way real salt does. If your machine has a reservoir, keep it filled.
- Mistaking etching for hard-water film. If your glasses stay cloudy after a vinegar rinse, it may be etching, which comes from water that's too soft plus too much detergent. Salt won't fix that. Learn to tell them apart in cloudy glasses: etching or hard water?
Refilling without a mess
Use the funnel that came with your dishwasher if you still have it, or a wide-mouth kitchen funnel. Unscrew the cap, set the funnel in, and pour slowly until salt reaches the neck of the reservoir. Some water will overflow as the salt pushes it out. That's normal and why you run a cycle afterward. Wipe salt grains off the threads before you screw the cap back on, because grit on the threads is the most common reason the cap leaks or gets stuck.
When the problem isn't salt at all
If you have no reservoir and you're still getting white film, your dishwasher has no built-in softener and salt won't help. Look at rinse aid, detergent dose, and water temperature instead. Our troubleshooting guide on white film on dishes is the place to start. Hard water keeps working on the heating element whether you see film or not, and scale on the dishwasher heating element explains what that costs you over time.