Dishwashers are fantastic.

But what can we do when they stop working properly?

If your dishwasher is not washing the dishes on your top rack, there are a few different reasons why this might be happening.

Keep reading to find out how to fix this.

How Does a Dishwasher Work?

When it comes to finding out what problems you might be dealing with it is always a good idea to get a basic working knowledge of how the actual machine works. Dishwashers do not have a constant flow of water as you might imagine. The water flows into the dishwasher and collects at the small basin in the bottom. The water is then heated by a heating element and the detergent is released by the computer of the dishwasher.

After that the water is pumped up through the two sprayer arms in the dishwasher by the pump that is located in the center of the machine. The dishwasher then proceeds to cycle this water through the sprayer arms for a predetermined amount of time based on the cycle that was chosen and on cues that come from the computer of the dishwasher. The soapy water then drains out and clean water comes in.

This clean water then goes up through the sprayer arms to clean the dishes and to remove any remnants of food or detergent that might still be present. This process helps to make sure that the dishes are clean and that they are clean and ready to be used. The dishwasher may also have a heating or drying cycle in which the air inside the dishwasher is heated to help dry the dishes and even sanitize them in some cases depending on the overall cycle that was chosen.

Front Photo Of An Open Dishwasher With Tableware
The detergent is released into the appliance by the timer. The hot water and detergent are sprayed by the rotating arms around the dishwasher, cleaning off dirt and debris.

Why Your Dishwasher Isn’t Cleaning The Top Rack

Low Water Pressure

The first and most common issue is low water pressure. In order for water to be forced up through the top sprayer arm as well as the bottom sprayer arm there has to be adequate water pressure. Low water pressure is going to make it impossible for enough water to be sprayed with a great enough force to both distribute the detergent and then spray the food or other build up off of the dishes that are on your top rack.

If your water pressure is too low, the water coming out of the top sprayer arm, if any, is going to be far less powerful than it needs to be and it is likely not going to adequately wash your dishes that are on the top rack. There are a few different reasons that your water pressure might be off. The first is that you have too many appliances that are all using water at the same time. A great way to think about it is when you flush the toilet when the shower is running. It does not change the temperature as it used to, but it does make the water pressure of the shower go down for a moment or two. When you are using the washer, the tub, the shower and the dishwasher all at once your water pressure is going to be affected.

Water pressure can also be affected by a kink in the dishwasher hose, a filet that is overly full and needs to be cleaned, and even an issue with your water line. The best way to fix this problem is to first do a test. Run only the dishwasher and see if it works properly and cleans properly. If it does, this means your water pressure is off because you have too many things going at once. If it is still not working properly, clean the filter and try again. If that does not work you may need to pull your dishwasher out and check the hose to make sure that it is free of kinks and other issues.

Sprayer Arm Seal is Broken

Another reason your top rack dishes may not be getting clean is that the seal for your upper sprayer arm is bad. The sprayer arm is made of two parts that are sealed together to force water up and to clean the dishes. If the seal is broken, the water is going to leak out around the seal instead of being forced up to wash the top rack dishes.

You can remedy this issue by replacing the seal or replacing the upper sprayer arm. You can have a technician come and do this repair for you or you can work on it yourself and get the upper sprayer arm working again.

Sprayer Arm is Clogged

Another problem you might be dealing with is a clog in the sprayer arm. This is most common in areas where hard water is common or where there are excess minerals in the water. Since the water in the dishwasher is recycled during the cleaning process, the arm can also get clogged with detergent, food and other particulates that might be in the water.

To check and see if your sprayer arm is clogged you do need to remove it and clean it thoroughly. With cases of hard water, you may need a calcium remover or a mineral remover to get rid of the deposits that are causing issue. Cleaning your sprayer arm is relatively easy. It pops off and you can check to see if there are any clogs. Cleaning your sprayer might not be something that you think about, since washer is literally in the name. But your sprayer arm does need to be cleaned ever so often.

A sprayer arm working
If the sprayer arm is working properly it should have enough pressure to remove food debris from the dishes.

Your Dishwasher is Dirty

The last possible cause for a dishwasher that is not cleaning properly is that the dishwasher itself is dirty. If the dishwasher is dirty, if there is a build up in the filter or in the sprayers, or if the dishwasher has unnecessary build up it can cause all sorts of problems. Your dishwasher needs to be cleaned on a regular basis.

You should be cleaning your dishwasher at least once a month in terms of a routine clean. This means wiping it out, changing or cleaning the filter, and making sure that there are no clogs that are causing issues. You can also do a deep clean every few months to make sure that the dishwasher is clean and is not going to be causing problems.

Routine cleaning can help to prevent a ton of problems and can help you to make sure your filter is going to work and that it is going to last longer and work well the entire time that you have it in your home. You can buy cleaners that you can use in your dishwasher that will help break down any problems and that will break down any build up that might be causing problems.

Dishwashers are great. They can help cut down on time that you have to spend doing chores and they can help you get dishes that are clean and sanitized. When they do encounter issues, they are often simple problems that can be fixed quickly if you just take a little time to look at the dishwasher closely. Taking the time to inspect each part can help you identify the problem and figure out what needs to be cleaned or replaced rather than having to replace your entire machine.

These are just a few issues you might be dealing with that you can determine or identify on your own. If the issues persist or if they get worse it is always a good idea to consult the owner’s manual for your particular machine or to contact customer service. You may also need to contact a technician or repair service to come and see what might be going on with your dishwasher.