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Dishwasher Not Cleaning Dishes

Bryan enjoys saving money by doing DIY home repairs. He likes to share his experiences with others to save them money, too.

A few easy steps will have your dishes come out clean every time.

A few easy steps will have your dishes come out clean every time.

So Your Dishes Aren't Coming out of the Dishwasher Clean

Getting a dishwasher to actually clean your dishes can sometimes be a hassle. Most assume that the dishwasher itself is to be blamed, and that may be true, but more often, clean-ability issues have more to do with factors that even a brand new dishwasher will not solve.

One of the first things to consider when diagnosing a dishwasher that isn't cleaning properly is the hardness of your water. Minerals, such as calcium and magnesium in your water supply, play a big roll in how well a dishwasher can clean your dishes.

On the other hand, soft water, which has little to no dissolved minerals in it, can pose problems as well. Although not as tricky as hard water to deal with, it can certainly give its fair share of trouble.

Both soft and hard water conditions pose challenges that can be overcome by simply understanding the relationship between water hardness and detergent.

When your glasses like these come out cloudy, it's time to check if you have minerals in your water.

When your glasses like these come out cloudy, it's time to check if you have minerals in your water.

Phosphates and Detergents

In recent years, it has become increasingly difficult to get clean dishes because phosphates have been removed from dishwasher detergents. Phosphates are a human-made, inorganic chemical that has been proven to be a threat to the environment. Local governments have been phasing them out state-by-state, and now it is illegal to sell dishwasher detergent with phosphates in the US.

The benefits of detergents with phosphates were that they didn't react to the minerals in the water as organic detergents do, and they dissolved food on contact. The effectiveness of a natural detergent is compromised when it comes in contact with hard water. The calcium and magnesium in hard water combine with organic chemicals in soap to produce another chemical altogether. The chemical produced by these two is lime, which shows up as soap scum, or a cloudy scale that coats the dishes and the inside of the dishwasher.

Phosphates were the perfect chemical additive for dishwasher detergents because they did all of the work. They were the ideal chemical for both neutralizing the effects of water hardness and for dissolving food matter. Since phosphates have been removed, it has become an endeavor for detergent companies and consumers to figure out how to get past these challenges posed by hard water and food residue.

Dishwasher with caked on lime deposits.  Time for CLR and white vinegar.

Dishwasher with caked on lime deposits. Time for CLR and white vinegar.

What to Do If You Have Soft Water

One of the easiest solutions in dealing with hard and soft water is to change the amount of detergent used according to how soft or hard your water is. Simply, if you have soft water, then you should use less, and if you have hard water, you should use more.

Because little to none of the detergent is being converted to lime in a soft water condition, all of it is being used for cleaning the dishes. Manufacturers of dishwashers and dishwasher detergents engineer their product to account for some of it being wasted due to its reactions with average water hardness. Because normal levels of water hardness will neutralize some of the detergent, they design soap dispensers and detergent tablets accordingly.

If you have soft water, and you use a normal amount of detergent, then it will be too much detergent and will over-suds in the dishwasher. If a dishwasher has too much detergent, it cannot rinse all of it off, and your dishes will come out with soap residue on them. Over-sudsing also compromises how well a dishwasher can spray the dishes. When water is too soapy, it also weakens the cleaning power of the dishwasher's wash pump.

One easy way to see if your dishwasher is over-sudsing is to turn it on without detergent. Let it fill and wash for a couple of minutes. Open the door and see if any suds are sitting on top of the water. If there are, then you are using too much detergent for the type of water that you have. It would be a good idea to let it finish the cycle to allow the leftover soap residue to rinse out, and then start the next cycle using less detergent. This should significantly improve your dishwasher's efficiency.

White vinegar is great upkeep for removing calcium deposits.

White vinegar is great upkeep for removing calcium deposits.

For tough cases of soap scum and lime buildup, CLR is the best option.

For tough cases of soap scum and lime buildup, CLR is the best option.

What to Do If You Have Hard Water

Soft water is easier to deal with than hard water. Hard water is where the real challenges start!

Because the combination of hard water and detergent forms soap scum, it is important to understand that some of the detergent you use is going to waste. You will need to compensate for the wasted detergent by adding more to get your dishes properly clean. This will vary based on how many minerals are in your particular water. The more minerals you have, the more detergent you will need to add to balance it out. Although, you shouldn't have to put any more in than your dishwasher's dispenser cup can hold.

The main difficulty with hard water isn't just cleaning the dishes, but rather preventing the white film from forming. If you are experiencing cloudiness, that means you have a buildup of lime deposits in the dishwasher that needs to be cleaned. There are many ways to do this. The easiest way is to run an empty cycle with about a cup of white distilled vinegar. This will dissolve soap scum build up and will also dissolve food particles that may have accumulated in the dishwasher.

How to Use CLR to Remove Soap Scum

Dishwashers that have an excessive amount of soap scum buildup will need something with a little more power. CLR is the best product to use to clean out heavy soap scum and lime deposits. Before doing the following steps, make sure the dishwasher is empty.

  1. Start an empty wash cycle and wait until the dishwasher starts to fill.
  2. Open the door and pour 1/2 cup of CLR into the bottom of the dishwasher and let it finish its cycle.
  3. Run another empty cycle after this to rinse the cleaning chemical completely out of the dishwasher.

After using CLR to clean the heavy deposits, repeating the process once a month with white distilled vinegar should stay on top of the accumulation so that the heavier chemicals are not needed.

The following video from GE has instructions on how to run a clean cycle with different product recommendations as well.

GE Instructional Video

A rinse aid can solve many problems with spotty and cloudy dishes.

A rinse aid can solve many problems with spotty and cloudy dishes.

Rinse Aid

It is also important to use a rinse aid, especially with hard water. Rinse aids treat the outside of the dishes so that the water will sheet off of them thus preventing spots and filming. The product works a lot like Rain-X does on car windshields in the rain. By not allowing the water to bead on the glass, the wind keeps the windshield clear, so you can drive in the rain with greater visibility. Rinse aid works the same way by not letting the water bead on the dishes. Gravity will cause the water to fall off of the dishes, so they will not spot or film and will dry more easily.

It is also a good idea to turn your hot water on at the kitchen sink before turning on your dishwasher. Newer dishwashers are built to be more efficient, which means that the functional parts, such as the heating element, are made weaker to save energy. The heating elements are not powerful enough to heat up cold water and rely on the water already being hot by the time it enters the machine. By starting the cycle with hot water, the dishwasher's cycle can finish at a higher temperature which allows excess water to evaporate off of the dishes to better dry them, and will reduce the potential for spotting and a cloudy film from appearing.

Detergent Enzymes

Detergent enzymes run the anchor leg of this race. After phosphates were outlawed, they needed to be replaced by something that would dissolve food on contact, while still being environmentally friendly. Detergents with added enzymes have proven to be the best substitute for phosphates, but because they are natural, they are not as easy to work with.

Phosphates did an amazing job at dissolving food without us even noticing, but enzymes need our attention to get them to work efficiently. Enzymes will do the job of dissolving food, but the food matter on the dishes cannot be dry. The enzymes can only react with fresh food matter on the dishes to properly do their work.

If the dishes have dried food on them, or have been completely rinsed off, the enzymes will stay in their crystallized form and will not be utilized at all. In addition to them not being utilized, they can start to etch the finish of your dishes and glassware. When the dishwasher sprays water with crystallized enzymes in it, it can actually attack the finished surfaces of the dishes with a sandblast-like effect. The only way for them to completely dissolve is to come in contact with organic food matter.

To get the best results, it is recommended to scrape off solid food matter, without rinsing, and run the dishwasher before what is left on the dishes has a chance to dry. This allows the enzymes to dissolve food matter as effectively as phosphates. It can be a bit of a hassle to change old habits, but gaining an understanding of the kind of water you have is immensely helpful. You can easily form new habits when you finally achieve clean dishes without the use of phosphates.

If you are unsure about the condition of your water, test strips can be purchased at most stores, and they are easy to use. Knowing your water is the key to understanding how to get the cleanest dishes possible.

Quiz Time!

For each question, choose the best answer. The answer key is below.

  1. Phosphates Are What Kind of Chemical?
    • Man made, inorganic
    • Naturally organic
    • Neither
  2. Water That Has Dissolved Minerals in It Is?
    • Soft Water
    • Hard Water
  3. If Your Water Has a Normal Amount of Mineral in It You Should...
    • Use LESS than the recommended amount of detergent
    • Use MORE than the recommended amount of detergent
    • Use the recommended amount of detergent
    • Use none at all
  4. What Should You Do After Rinsing out Your Dishwasher with CLR?
    • Pour yourself a glass because CLR is good for digestion
    • Run another rinse cycle with nothing in it
    • You're good to go. Load your dishes.
  5. What Do Enzymes Need to Be Activated?
    • Just add water
    • An over-ripe banana in the silverware basket
    • Non solid food that hasn't dried yet

Answer Key

  1. Man made, inorganic
  2. Hard Water
  3. Use the recommended amount of detergent
  4. Run another rinse cycle with nothing in it
  5. Non solid food that hasn't dried yet

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.