Dishwasher Salt May Be the Secret to Extra Clean Dishes

If you are lucky enough to have purchased a high-end dishwasher recently, you may have noticed something odd lurking under the bottom rack—a little receptacle marked "add salt." This is not the salt you use to add flavor to your dishes, but a special cleaning salt to help your dishwasher get your dishes to shine.

Dishwasher salt, which is sold in stores and online by companies like Finish Salt or by dishwasher manufacturers like Bosch or Miele, is there to help soften water and prevent those pesky spots that show up on dishes if you happen to live in a so-called hard-water area.

What is Hard Water?

Your water is considered "hard" not when it's frozen, but when it has high levels of calcium and magnesium in it. Hard water is harmless to humans but can wreak havoc on things like home water heaters and pipes. When the calcium and magnesium combine with dishwashing detergent, it can turn the soap into a clump, which makes your dishwasher less efficient and causes that unsightly, spotty residue on your wine glasses. Hard water can also cause limescale buildup on your utensils and appliance. Your local water utility likely provides reports indicating the hardness or softness of the water.

How Dishwasher Salt Works

Dishwasher salt is designed to counteract that. According to Realtor.com, large-grained dishwasher salt is made up of pure sodium chloride, which bonds (remember that from chemistry class?) with the calcium and magnesium in the water, making them harmless. The result of this "softening" process is cleaner dishes, a longer-lasting dishwasher, and spot-free glassware.

"Putting salt in your dishwasher might seem strange at first, but dishwasher salt is actually an excellent tool for keeping your unit operating at maximum efficiency," Doug Rogers, president of Mr. Appliance, explained in an interview with Realtor.com.

On the other hand, if you live in an area with soft water, you won't get much benefit from dishwasher salt.

How to Use Dishwasher Salt

If your dishwasher does come with a salt dispenser, it's easy to use. There are even how-to videos on YouTube giving step-by-step instructions on how to refill them, and while it's nothing like topping up your table salt and pepper shakers, it's simple enough:

1. Locate the salt reservoir: Dishwasher salt should only be used if your appliance has a designated salt reservoir. Pull out the bottom rack to locate the reservoir, which usually has a screw cap.
2. Unscrew the cap and fill: Unscrew the cap from the reservoir. Fill with salt to just below the lip, and don't worry if there is water in the reservoir—it's designed to get wet.
3. Replace the cap and rack: Screw the cap back onto the reservoir and tighten it. Replace the rack in the dishwasher.

What if I Don't Have a Dishwasher Salt Reservoir?

An older dishwasher may not have a reservoir for dishwasher salt. If you have hard water but don't have a reservoir, you can try all-in-one dishwasher tablets that contain dishwasher salt. Use in place of your usual detergent each time you run a load.

When to Refill Dishwasher Salt

Modern dishwashers usually have an indicator light that tells you when it's time to refill your dishwasher salt reservoir. An older appliance may have a float indicator that will clue you in when you're running low. And of course, you can always check the reservoir if you think it's time to top off the dishwasher salt.

Can You Use Table Salt in the Dishwasher?

If your dishes have been lacking that sparkling-clean feeling and your favorite water glasses look practically polka-dotted, dishwasher salt may be the solution for your water softener-compatible washer—but to prevent other problems be sure to tell your family not to add any table salt to the dishwasher. Though both include sodium chloride, the fine grains of table salt can cause clogging and residue.