7 Signs of Hard Water in Dishwasher to Fix

Last Updated on December 14, 2022 by Claire

This publication reveals the signs of hard water in dishwasher if you’re unaware of whether yours is hard or soft. Hard water contains high mineral deposits that leave a residue or film on various kitchenware and surfaces. The same mineral deposits that cause hard water buildup also leave the toughest stains on your dishes and glassware even after many rinse cycles in the dishwasher.

Although not hazardous to your health, hard water can damage your dishwasher, dishes, and glassware if not kept in check. This is unfortunately what millions of people have to deal with every day. 

Worried your dishwasher isn’t doing its job properly and you’re not sure if it’s due to hard water or a major fault? Don’t call the technician right away.

Here are a few prominent signs you need to keep an eye out for to see if you have hard water running through your dishwasher.

Signs of hard water in dishwasher

Signs of hard water in dishwasher

If you suspect hard water in your dishwasher, look out for the following:

1. Water or Cloudy spots on dishes

Water or cloudy spots are the most visible and noticeable effects of hard water on your dishes. It is most noticeable on clear glassware and silverware. These cloudy white residues are a result of those mineral salts which are left behind when the water evaporates from your dishes.

These mineral salts also build up on almost every surface of your dishwasher leading to rust and damage to expensive components like pumps and heating elements.

2. Odd-smelling dishes

An odd and fairly harsh metallic odor on your dishes after a cleaning cycle is another sure way to know if your dishwasher is dealing with hard water.

Hard water may leave an odd, sometimes mild, or strong metallic odor on your dishes, making them unpleasant to use.

3. Too much detergent and Soap scum

Getting cloudy and odd-smelling dishes from your dishwasher after a wash cycle might make you think that you just need to add a little more detergent than usual, but don’t do that!

Applying too much detergent to your dishes can actually build up soap scum in your dishwasher.  This makes it not only harder for your dishes to get a proper wash, but can also leave behind soap residue and traces of bacteria on your dishes.

This is because the minerals in hard water find it difficult to form a solution when combined with cleaning products, resulting in the scaly, white soap scum left behind in your kitchen appliances.

In addition to this, you will have to deal with the added costs of purchasing dishwashing detergent more frequently than you need to. 

4. Signs of rust or corrosion on parts of the dishwasher

Corrosion begins immediately as hard water begins flowing through your dishwasher, although it might only be noticeable after a few months.

Hard water causes rust and corrosion because some of the mineral deposits left behind are actually salts (see Winston Food Service).

Salts are bad for metal parts because when metal is exposed to salt for long periods, over time it will eventually start to rust or corrode, although how fast this happens depends on what type of metal it is.

But the fact is no matter what type of metal it is, if it starts to rust or corrode, that’s bad news because that metal part isn’t going to last long before falling apart.

5. Chalky deposits

A dishwasher that doesn’t work won’t clean dishes well.

Chalky deposits will clog up any movable parts and cause the dishwasher to stop working or cause extensive and irreversible damage to your dishwasher.

6. Your dishes aren’t clean after wash

If you notice your dishes are coming out with food on them after a wash cycle in the dishwasher, you have a big problem with your hands.

Although this isn’t directly caused by hard water, it’s a result of the damage hard water has done to your dishwasher over time.

The mineral deposits that build up on the components can cause clogs, corrosion, and damage to your dishwasher over time. This will prevent the dishwasher from doing its job properly, and eventually kill the dishwasher or parts. 

7. Shorter lifespan of your dishwasher

Typically, dishwashers are supposed to have a lifespan of between nine to eleven years, but the prolonged effects of hard water will severely shorten their lifespan. 

Mineral deposits build-up in your dishwasher will affect its efficiency and cause frequent breakdowns, forcing you to call a plumber or technician for help. 

This will further increase your expenses, or force you into buying a new dishwasher even when you didn’t budget for it. 

How to remove hard water stains from a dishwasher

You use anything from simple household ingredients to commercial products to remove hard water stains.

Here are a few simple ways you can clean stained dishwashers:

  1. Use hard water detergents.
  2. Use rinse aids to help water to rinse off of your dishes and glasses, so it can drain and evaporate away more easily without leaving spots or residue on them.
  3. Add a water softener to your water supply system to boost the cleaning power of your dishwasher.
  4. Frequently rinse your dishwasher with vinegar to lower the water’s pH level. Thus making minerals, such as magnesium and calcium more soluble in water.

What can I do to prevent hard water residue?

  1. Always run regular vinegar cycles to help prevent mineral deposits from building up inside the dishwasher.
  2. Use a rinse aid and citric acid for each wash cycle to remove any hard water residue from dishes and the dishwasher. You can do this by adding a teaspoon of citric acid to your detergent for each load or putting 3 to 4 tablespoons of citric acid in the detergent dispenser, and then running an empty load at normal ‘level’ to clean out any hard water residues.
  3. Using a sodium-based detergent helps to soften the water.
  4. A more permanent solution for removing hard water deposits is the installation of a soft water system for the house. Soft water is more effective for cleaning and lathers more easily than hard water.
  5. Don’t use too much detergent. Many people make the mistake of adding more dishwasher detergent to get a better wash with hard water, but unfortunately, the soap doesn’t completely rinse off, resulting in more residue.

How often should I clean a dishwasher?

Regular cleaning of your dishwasher kills bacteria and prevents residual buildup on your dishes.

Ideally, you should clean your dishwasher at least every 2 months or once a month if you use it more than twice a day to ensure your dishes are properly cleaned.

You can do a quick soft cleaning or deep cleaning of your dishwasher to keep it in tip-top shape.

How to soft clean a dishwasher

  1. Fill a measuring cup or dishwasher-safe glass bowl with white vinegar
  2. Place the vinegar dish on the bottom rack
  3. Run the dishwasher on a full cycle
  4. Use a clean rag to wipe out the inside of the dishwasher when the cycle is completed
  5. Try running another wash cycle if there is still a strong smell of vinegar noticeable. This should help to flush out the remaining vinegar. You can also consider adding a tablespoon or two of baking soda to help absorb the scent and run another cycle.

A quick soft clean is recommended every 2 months to prevent the build-up of debris and grease, or when you begin to notice white residue or grease on your dishes

How to deep clean a Dishwasher

  1. Spray a degreasing agent inside the dishwasher and then wipe clean
  2. Run the vinegar through a rinse cycle
  3. Unplug the dishwasher when the cycle is completed
  4. Remove the bottom and top rack of the machine and soak them in hot water mixed with vinegar
  5. Remove the dishwasher fan (follow your manufacturer’s directions in the dishwasher’s user manual)
  6. Use a thin wire to clean out the spray holes and rinse thoroughly
  7. Return the fan and racks to the dishwasher
  8. Plug the machine back in and run a wash cycle without soap to rinse everything

Deep cleaning is advisable at least twice a year to prevent any residue or grease from accumulating in the expensive components and hard-to-reach parts of the dishwasher.

What dishwasher cleaners can I use?

You can check online for other options or simply use any of the dishwasher cleaners listed below to prevent or get rid of hard water residue in your dishwasher:

  1. Finish dishwasher cleaner
  2. Frigidaire probiotic dishwasher cleaner
  3. Affresh W10282479 dishwasher cleaner

How to properly load a Dishwasher?

Here’s how to properly load a dishwasher to avoid residues (always check your dishwasher’s user manual for any special loading instructions):

1. Upper rack

Concave-shaped items such as glasses, mugs, bowls, utensils, silverware, and dishwasher-safe plastics prevent warping.

  • Angle bowls facing the center with spaces in-between them to prevent breakage, and also to allow water and soap to reach them.
  • Glasses and mugs must be placed between the tines and not on them.
  • Place large silverware and utensils horizontally.
  • Utensils must be properly secured with long handles so they don’t fall through and stop the spray arm from rotating.

2. Lower rack

Platters, plates, larger utensils, and cooking utensils.

  • Arrange plates and platters vertically.
  • Stagger small and large pieces so water and detergent can reach the top rack.
  • Place oversized items such as dishwasher-safe cutting boards, along the perimeter.

3. Utensils rack

All types of utensils can be put here.

  • Make sure you load forks and spoons with their handles facing down.
  • Always load knives with the handles facing up.
  • Mix up cutlery items to prevent them from nesting together, resulting in incomplete washing and rinsing.
  • If using a utensil rack: lay each item flat and don’t overlap them to ensure that each item can be cleaned properly.


Always remember to properly scrape off your dishes before putting them in the dishwasher to prevent grease build-up as large pieces of food can become lodged in the dishwasher drain causing it to get clogged up. The more debris in the dishwasher drain, the harder it is for the grease and food to exit properly, and the easier it is for hard water deposits to build up.

Hard water damage occurs over time and is not instantly noticeable unless you are able to notice the tell-tale signs on time. You can limit the effects if you take certain precautions on time to prevent them from resulting in major and expensive damage to your appliances.

Consistent, regular cleaning and installation of a soft water system will also prevent hard water residue build-up in your dishwasher.