Dishwasher Salt May Be The Secret To Extra Clean Dishes

Sparkling clean glassware may make this extra purchase worth it.

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

Dishwasher salt, 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 appear on dishes if you happen to live in a so-called hard-water area.

Clean White Dishes in Dishwasher
Hero Images/Getty Images

What Is Hard Water?

The term "hard" water does not reference frozen water, but when it has high levels of dissolved calcium and magnesium. 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 counteracts hard water. According to, large-grained dishwasher salt consists of pure sodium chloride, which bonds (remember that from chemistry class?) with the calcium and magnesium in the water, making them harmless. This "softening" process results in cleaner dishes, a longer-lasting dishwasher, and spot-free glassware.

"Putting salt in your dishwasher might seem strange at first, but [a] 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

On the other hand, if you live in an area with soft water, you won't benefit much 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: Only use dishwasher salt 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 water is 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.
Dishwasher Detergent Tablets
Kuzmik_A/Getty Images

What If A Dishwasher Doesn't Have A 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 it instead 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 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 to see if it's time to top off the dishwasher salt.

Can You Use Table Salt In The Dishwasher?

If your dishes lack 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. Tell your family not to add table salt to the dishwasher to prevent additional problems. Though both include sodium chloride, the fine grains of table salt can cause clogging and residue.

Was this page helpful?
Southern Living is committed to using high-quality, reputable sources to support the facts in our articles. Read our editorial guidelines to learn more about how we fact check our content for accuracy.
  1. U.S. Geological Survey. Hardness of water.

Related Articles