Dishwasher Problems Caused by Hard Water

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Having hard water is pretty common for most households in North America. In fact, 85% of homes in the U.S. use hard water. While hard water isn’t dangerous, it can often be inconvenient and sometimes costly to deal with.

In particular, dishwashers and other appliances that use water are susceptible to issues caused by hard water. If your water is too hard, over time it’ll leave your dishwasher unable to properly wash your dishes, and it may even damage your dishwasher eventually.

In this article, we’ll explain what you need to know about hard water and how it can affect your dishwasher, and we’ll also show you what you can do to deal with dishwasher issues caused by hard water.

Related: How to Winterize a Dishwasher

What Is Hard Water?

Hard water is water that has a high mineral content. The bulk of the mineral content in hard water usually consists of calcium and magnesium, although it may contain trace amounts of other minerals as well.

Credit: Kinetico Water Systems

Hard water is safe to drink and wash with, although it often has a weird, somewhat salty taste that you may find somewhat off-putting. The main problems with hard water stem from the fact that it tends to damage any materials it comes in contact with for a long period of time.

The most obvious signs that your house has hard water are the presence of:

  • Scale(limescale) on your faucets
  • Low water pressure
  • Chalky stains on your dishes.
  • Any fabrics you wash in hard water will start feeling kind of rough, and showering in hard water will give you dry hair and skin.

The hardness of water is usually measured in parts per million (ppm). This refers to the concentration of the minerals per liter of water. For example, if the concentration of calcium in your water is 1 ppm, that means that there’s 1 milligram of calcium in every liter of your water.

As for how high the mineral content needs to be in your water before it can be considered “hard”, here’s about how it breaks down:

  • Water with a mineral content of between 10-50 ppm is considered soft water.
  • Water with a mineral content of between 50-100 ppm is considered slightly hard water.
  • Water with a mineral content of between 100-200 ppm is considered hard water.
  • Water with a mineral content of 200 ppm or more is considered very hard water.

In general, the Pacific Northwest tends to have fairly soft water, while the midwestern and southwestern American states and the Canadian Prairies tend to have harder water. 

You can read more about hard water by visiting USGS.GOV

How Does Hard Water Affect My Dishwasher?

As we’ve mentioned, hard water in a home usually has the greatest impact on appliances like dishwashers that use water. You’ll also notice the signs of hard water on any dishes you wash in it, as we’ll explain shortly.

In this section, we’ll go over the problems hard water can cause for your dishwasher and what you can do about this. 

Residue On Your Dishes

If you notice that your clear glassware and dishes are looking strangely cloudy or chalky after washing them, this is a sign that you have hard water in your home.

The cloudy appearance comes from the mineral deposits in your water, which adhere to your glassware and remain there once the water from your dishwasher evaporates.

Plates, glasses, and utensils that are coated with this residue are still technically safe to eat with but may impart a strange taste to any food or drink you have them with.

Plus, it just doesn’t look that nice to have a bunch of weird white stuff coated all over your supposedly clean dishes.

Eliminating residue

If you want to eliminate this residue from your dishes, there are a couple of things you can do (although bear in mind that these are only temporary solutions for dealing with stained dishes specifically, and don’t solve the problem of hard water in your home).

The first thing you can do is try using a rinse aid. Rinse aids or rinse agents as they’re sometimes called contain surfactants, a type of chemical that is used to lower the surface tension of water.

Lowering the surface tension of the water inside the dishwasher prevents the water from forming droplets that cling to surfaces.

Instead, the water spreads out into thin sheets and easily slides off of whatever surface it comes into contact with. Not only does this prevent mineral deposits from sticking to your dishes, but it also helps your dishes dry out more quickly.

The other thing you can try is to use a dishwashing detergent that is specifically formulated for use with hard water.

Often, these detergents contain both surfactants and water-softening ingredients, which help dry your dishes off faster and break down some of the minerals that leave the residue in the first place.  

Residue In Your Dishwasher

With hard water in your home, it’s likely that you’ll start seeing the same residue that coats your dishes also coating the inside of your dishwasher before too long.

Compared to the residue on your dishes, however, the residue in your dishwasher is a greater cause for concern, as this residue can severely damage your dishwasher if enough of it builds up.

If you want to remove this scale buildup from your dishwasher, one cheap and easy way to do so is with cleaning vinegar.

Just fill a dishwasher-safe bowl or glass with a cup of cleaning vinegar, place it in the dishwasher, and let the dishwasher run once on a short cycle.

This works because cleaning vinegar contains acid, which breaks down the minerals on your water and helps the dishwasher flush them out on its own. You can also use cleaning vinegar in place of a rinse aid when washing your dishes.

Again, while using vinegar is a good way to remove any scale from inside your dishwasher, it’s not a permanent solution to the issue of hard water.

Don’t worry, though; there is a more permanent solution for dealing with hard water that we’ll share with you shortly.

Rust In Your Dishwasher

If you start seeing patches of rust appear on the inside of your dishwasher, this means that your dishwasher has been exposed to hard water for far too long.

Rust is obviously never a good thing to find in your dishwasher; it’s not exactly sanitary to wash your dishes in rusty water, and dishwasher parts inevitably break when they get too rusty.

Hard water causes rust because some of the minerals in hard water are salts. Saltwater is an electrolyte, meaning it conducts a mild electric charge.

Certain types of metal like iron or steel begin corroding when exposed to water and oxygen, and if an electrolyte gets thrown into the mix as well, the resulting electrochemical reaction greatly speeds up the rate at which rust forms.

If you notice rust in your dishwasher, your first move should be to replace any parts that have rusted out, if you can. If the damage is too severe, you may have to replace the entire dishwasher.

Rust in your dishwasher means that your water is probably a lot harder than average. In cases like these, the best thing to do is usually to install a water softener.

A water softener does exactly what the name implies; it removes the mineral content from hard water, thereby “softening” it. A water softener consists of a reservoir filled with resin beads containing negatively charged sodium ions.

Calcium and magnesium are positively charged minerals, and as you may know, opposite charges attract each other.

Therefore, when hard water flows through the reservoir of a water softener, the resin beads pull the minerals out of the water and keep them trapped in the reservoir.

You can find dishwashers with water softeners already built into them, or you can install a water softener to remove the hard water from your whole plumbing system if you prefer. 

Unclean Dishes

If your dishes keep coming out of the dishwasher with mineral residue on them, that’s one thing. If they keep coming out with bits of food still stuck on them, however, that’s another thing entirely. Both of these issues can be caused by hard water, however.

If your dishwasher is failing to clean your dishes properly, this is most likely due to the fact that mineral deposits have built up inside the water lines of your dishwasher.

If enough minerals get trapped in there, they can severely restrict the flow of water through the dishwasher, which as you can probably guess makes a dishwasher far less capable of doing its job.

If you’re looking for a quick fix to deal with a scaled-over dishwasher, cleaning vinegar is once again going to be your best bet.

In particular, you’re going to want to scrub down the sprayer arms in your dishwasher with some cleaning vinegar, since it’s likely that that’s where most of the clogging is happening.

Related: Dishwasher Not Cleaning Dishes On The Top Rack?

While you’re at it, also take the time to scrub anywhere you can reach inside your dishwasher with vinegar.

As always, removing scale buildup isn’t a permanent fix to the problem of hard water, but it’ll certainly prolong the life of your dishwasher at least a little bit.

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