Dishwasher Not Cleaning Top Rack: 13 Common Causes

If your dishwasher’s top rack is not cleaning, there are multiple things that could be going on. In most cases, there are relatively easy fixes to try. 

Fixing your dishwasher so it cleans the top rack properly normally means checking the water pressure. That can relate to clogs, blockages, loading, or the circulation pump. Clearing the blockage restores the dishwasher to normal. However, many things can go wrong, and it may be important to troubleshoot your dishwasher. 

How to Fix the Top Rack of Dishwasher: 13 Simple Ways 

There are many things that might cause your dishwasher to not clean the top rack. For example, low water pressure, low quality detergent, a broken diverter, and other issues. Normally, you want to start with the easiest fix first – cleaning your dishwasher. 

1. Spray Arms Being Blocked

If the spray arm is blocked by a pan, a large plate, or even a piece of the dishwasher mechanism, the top rack won’t clean. Most dishwashers rely on free motion of the sprayer arm, or the spinning jets at the top, in order to clean. Therefore, you should always make sure the spray arm can spin freely before you turn the dishwasher on. To do so, consider giving it a spin with your hands. If it hits something or makes a noise while running, it’s likely being blocked by something. 

It’s also important to check that the spray arm isn’t being blocked by something wrapped around the mechanism. For example, brush fibers, hair, or even string can wrap around the top of the mechanism. Cleaning that blockage out of the mechanism can restore your dishwasher to normal. 

2. Spray Arms Being Clogged

Clogs in the spray arm or rather in the jet holes on the spray arm might also cause your dishwasher problems. Clogs normally occur because of calcification or lime buildup. However, they might also relate to detergent or other buildup. You can normally easily take the spray arm out of your dishwasher by twisting it and snapping it out. However, some dishwashers use a bolt assembly. Others also don’t allow you to change the spray arm. In this case, you’ll want to take the racks out of the dishwasher so you can access the spray arm. 

If you can take the spray arm out, soak it in a bucket for 24 hours. The bucket should contain 1 part vinegar and 4 parts water. Then, use a toothbrush or a bottle brush to clean out each of the jets. If there’s any hard buildup, use a skewer or another metal object to scrape it out. 

3. Overloading

If you overload your dishwasher, it will always have trouble cleaning. Your dishwasher needs space for water to flow between dishes, for the spray arms to turn, and for the brush to turn. If you consistently have too many dishes, try running the dishwasher a bit more often – or replace it for a larger model. 

4. Improper Loading 

Most dishwashers have a recommended loading schematic in the manual. If you check it and you are loading in a different way, you may want to change that. Improperly loading a dishwasher can cause water and airflow issues, can block the water jets, and can block the physical movement of the arm. For example, if you cover the top with flat plates, it may prevent liquids from cleaning the underside of plates. 

In most cases, the actual problem normally depends on how your dishwasher is supposed to load. 

5. Low Water Pressure

Low water pressure means that the dishwasher doesn’t jet water at enough speed to properly clean dishes. In this case, the low water pressure actually means that the circulation pump isn’t getting enough water. This can cause multiple problems, including the pup burning out. However, if your dishwasher functioned normally at first, it’s unlikely that the low water pressure issue is your home’s water pressure. 

Instead, it might relate to a bend or a kink in a water line. It might also relate to clogged or blocked filters between the water line and the pump. Or, it could relate to built up sedimentation in the lines. You can always clean your dishwasher out using a vinegar and water solution, clean the filters, and check the pipes for kinks. If your home’s water pressure is low, you’ve found the problem. That can be quite a bit harder to correct without installing either a pump or a cistern. 

6. Defective Circulation Pump 

The circulation pump normally sits in the bottom left of the dishwasher, at the water inlet. This pump pushes water upwards, at speed, so that it sprays the dishes with enough force to clean them. In most cases, it’s behind the heating element. The dishwasher pump is also usually reverse flow – meaning that it pumps water in and pressure and then pumps water back out. However, some older models might have two pumps instead of one. This is rare, so you shouldn’t expect it. 

For this reason, the easiest way to diagnose a defective circulation pump is that your dishwasher might do a poorer job of removing water. However, it might also do just fine. In this case, you want to pay attention to the pump when it kicks in. If it’s louder than it used to be, it might be having problems. Here, you can either take the pump out and clean it or replace the pump. What kind of pump? Any reverse flow pump, as available at a local hardware store, that fits, will do. However, most people will prefer to look up their brand and model to replace it with an OEM part to ensure the pump will fit. Most plumbers and dishwasher repair technicians can complete the work as well. However, rates will vary. 

7. Detergent Quality 

If you’re using a low-quality detergent, your dishes might not clean properly. Some detergents not intended for a dishwasher can even leave your dishes feeling gritty. So, you may want to make a trip to the store to buy a quality dishwasher tablet, intended for your dishwasher type, before trying any troubleshooting other than cleaning the machine. 

8. Diverter

Every dishwasher includes a diverter to control water flow between the upper spray arms. If the top rack isn’t getting clean, the diverter may be the cause. Here, the diverter valve functions much like a shower valve in a bathroom with a bathtub. When you turn the shower on, the tub faucet no longer works because the water is diverted to the shower head.

In this case, you’ll want to look up the diverter motor and diverter seal in your manual or on the internet. Then buy both new. In addition, if your diverter motor is bad, the dishwasher should technically tell you with an error code. However, that may not always be the case. Still, it’s always a good idea to check basic troubleshooting first. 

9. Temperature Setting

The heating element in your dishwasher is designed to heat water up to 100-180 degrees. The heat helps clean plates by dissolving starches, fat, and protein stuck to the dishes. If the water isn’t warm enough, it simply does not do that. Water might not be warm enough for a variety of reasons. For example, you might have accidentally turned the heat settings down. 

In some cases, your dishwasher will have a built-in thermostat you can adjust. In other cases, if your dishwasher is cooling down, it’s probably because you have a faulty thermostat or heating element. Here, the thermostat is the most likely culprit, because there’s little that can go wrong with a heating element. 

If you have an old-fashioned dishwasher, it might connect with your home’s boiler or hot water heater. In this case, make sure that your hot water heater heats water up to at least 120 degrees. 

What can you do if the thermostat is broken? You can buy a new one. However, most homeowners will want to hire a plumber or a dishwasher repair technician to fix the issue. 

10. Upper Arm Manifold 

The spray arm manifold or spray arm tube runs water from the pump to the spray arm. If this clogs, it will reduce pressure to the spray arm. Unfortunately, it can be quite difficult to clean out yourself. Here, many companies sell dishwasher cleaning solutions that insert decalcification chemicals into the dishwasher before the pump. In most cases, you install these by turning the water off, taking the dishwasher’s water line out at the wall, and installing a cleaning connection between the two. Then, you run the dishwasher several times. The dishwasher is forced to pull water through the cleaning attachment – meaning that the small internal bits like the upper arm manifold are cleaned and decalcified. 

11. Broken Spray Arm Seal 

The spray arm seal ensures a watertight seal between the spray arm and the manifold. Unfortunately, this seal can become lost, damaged, or torn. It’s a soft rubber ring that works to create a vacuum and funnel water into the spray arm – instead of out the sides around the fitting. If it’s lost or damaged, the pressure from the spray arm drops. Luckily, this part is easily replaceable. You can normally contact the manufacturer for a new piece. Otherwise, you can ask a local dishwasher repair technician if they have a suitable spray arm seal replacement. 

12. Water Inlet Valve Issues

Water inlet valve issues are the most common thing to go wrong with many dishwashers. This valve controls how much water goes into the dishwasher, how much of it is heated, and when it is drained. In most cases, it has an electric timer or other electronic control. If this is faulty, your dishwasher might not be getting enough water, might be heating the wrong amount of water, or might be draining water too quickly. In most cases, the inlet valve is the large plastic attachment on the back of the dishwasher. Your water line connects directly to it. In other cases, the water inlet valve is built in. If the inlet valve is leaking, you definitely have a problem. Otherwise, it can be more difficult to diagnose issues. However, you can always check to make sure the valve is not leaking. 

13. Clogged Filter or Chopper 

Clogged filters and choppers can change how water flows through the dishwasher, eventually affecting how the top rack is cleaned. For this reason, fully cleaning your dishwasher should always be a first step. Ideally, that means cleaning out all the filters and the chopper. This includes cleaning out the drainage mechanism, descaling the machine, and running any cleaning cycles you have. 

How Do I Get My Dishwasher to Clean Better? 

If your dishwasher isn’t cleaning well, there are plenty of steps you can take. Luckily, most of them are also relatively easy. 

Clean the Dishwasher

Thoroughly cleaning the dishwasher can do a lot for ensuring water is flowing through properly. Here, your largest concern is likely scale or calcification. Use vinegar or a product made for decalcifying your dishwasher. A thorough cleaning should also include cleaning out the filters and the drains. You may want to run the dishwasher’s clean cycle – with vinegar or a decalcifying agent in the detergent trap. 

Clean the Spray Arm and Seal 

The spray arm and seal are normally cheap and easy to replace. You can clean them by soaking in vinegar and scrubbing them. You might also want to replace them if either have been damaged. For example, if the sprayer arm is cracked, it will never clean as well. 

Check the Temperature

Most dishwashers clean the best between 120 and 150 degrees. If your dishwasher is cooler, it’s not warm enough to dissolve fat and protein from dishes. If it’s warmer, the heat could be causing motors to overheat and shut down. 

Use Different Detergent 

Detergent can make a big difference to how your dishwasher cleans. Try using a different brand if yours isn’t working that well. That’s especially true if you’ve recently switched brands or the brand you use has changed formula. 

Follow the Load Schematic 

Many dishwashers need to be loaded properly in order to clean properly. Follow the load schematic in the manual for your dishwasher for the best results. That means never blocking water flow, always keeping the sprayer arm free, and aiming to under load rather than overload your dishwasher. Most modern dishwashers use just 3-5 gallons of water per wash – it’s always better to run it with less water. 

Keep Rinse Aid Reservoirs Full 

Rinse aids fill the reservoir on the door in some dishwashers. If it runs out, your dishwasher will be less capable of cleaning dishes. Make sure you check if the rinse aid reservoir light comes on and make sure you always keep it full. 

Related Questions 

With so many things that can go wrong with a dishwasher, it’s understandable you’d still have questions. These related questions should help. 

Will dishwasher work without the top rack? 

In most cases, the dishwasher will run at a significantly reduced capacity if you remove the top rack. In most cases, the top rack adjusts water flow in the dishwasher. This means that removing it lowers water pressure. However, in other models, it does not matter. Check with your individual dishwasher manual. For example, some newer models include a removable top rack for the purpose of washing big pans. 

Can you lubricate dishwasher rack? 

You can lubricate the wheels of a dishwasher rack. However, due to the nature of a dishwasher, the lubricant will quickly wash off. In most cases, you are best off thoroughly cleaning the dishwasher rack, cleaning the tracks, and cleaning around the wheels. If you’d like to lubricate the wheels, spray a non-stick cooking spray into the wheels, turning them to ensure it gets into the mechanism. However, dishwashers use very hot water pushed through the full interior. Any lubricant you use will require frequent replacement. 

It’s also important to note that you should use a food grade lubricant. You can use something like WD-40, but chances are, it will come off quickly and might contaminate your dishes. 

What is the average life expectancy of a dishwasher? 

Most dishwashers have an average life expectancy of 10 years. Some will last longer; some will last less time. However, you can normally expect 10 years of normal functioning out of your dishwasher. 


If your dishwasher isn’t cleaning the top rack, there are plenty of things that could be going wrong. In most cases, it’s a good idea to start out by thoroughly cleaning the machine, checking the load schematic, and checking the water temperature. From there, specific problems can be more difficult to diagnose without an error code, but we’ve listed the most common issues you can try here. Good luck fixing your dishwasher.

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