How to Fix a Dishwasher That's Not Cleaning Dishes

A dishwasher that fails to clean dishes properly can be incredibly frustrating. Instead of sparkling clean plates and cutlery, you’re left with residue, spots, and the annoying task of re-washing everything by hand. Before you call a repair technician, however, there are several things you can troubleshoot yourself. This comprehensive guide will walk you through common causes of a dishwasher’s cleaning woes and provide step-by-step instructions to help you get your appliance back in top working order.

Table of Contents

Understanding Why Your Dishwasher Isn’t Cleaning

The first step to fixing a dishwasher problem is understanding the potential causes. A poorly cleaning dishwasher is rarely the result of a single issue, but rather a combination of factors. These can range from simple problems like improper loading to more complex issues involving the dishwasher’s components. Let’s examine the most common culprits.

Water Temperature Issues

Dishwashers rely on hot water to effectively dissolve detergent and remove food particles. If your water isn’t hot enough, the dishwasher won’t clean properly. Ideally, your dishwasher should receive water that is at least 120 degrees Fahrenheit (49 degrees Celsius). Anything lower, and the detergent won’t activate effectively, and food won’t be properly sanitized.

Checking Your Water Heater: The first thing to do is check your water heater’s temperature setting. Many water heaters are set too low to conserve energy, but this can impact dishwasher performance. Increase the temperature to 120 degrees Fahrenheit, but be careful not to set it too high, as scalding is a risk. Always consult your water heater’s manual for safety guidelines.
Running the Hot Water Tap: Before starting your dishwasher, run the hot water tap in your kitchen sink for a few minutes. This will ensure that hot water reaches the dishwasher quickly, rather than the dishwasher having to heat cold water from the pipes.
Testing the Water Temperature: Use a thermometer to check the water temperature at the kitchen sink. Place the thermometer in a glass and run the hot water until it’s as hot as it gets. If the temperature is below 120 degrees Fahrenheit, you’ll need to adjust your water heater.

Problems with Detergent

The type and amount of detergent you use significantly affect your dishwasher’s cleaning performance. Using the wrong detergent, too little detergent, or old detergent can all lead to poor cleaning results.

Using the Right Detergent: Always use detergents specifically designed for dishwashers. Hand soap or other cleaning products will create excessive suds and can damage your dishwasher. Dishwasher detergents come in powder, gel, and tablet forms. Experiment with different types to see which works best for your dishwasher and water hardness.
Measuring Detergent Correctly: Too little detergent won’t clean effectively, while too much can leave a residue on your dishes. Refer to your dishwasher’s manual for the recommended amount of detergent, and adjust based on the hardness of your water. Hard water requires more detergent than soft water.
Checking Detergent Freshness: Detergent can lose its effectiveness over time, especially if exposed to moisture. Store your detergent in a cool, dry place, and avoid using detergent that is clumpy or past its expiration date.
Detergent Dispenser Issues: Make sure the detergent dispenser is clean and functioning correctly. Residue can build up in the dispenser, preventing it from releasing the detergent at the right time during the wash cycle. Clean the dispenser regularly with a damp cloth or a small brush.

Spray Arm Issues

The spray arms are responsible for distributing water throughout the dishwasher, blasting food particles off the dishes. If the spray arms are clogged or damaged, the dishwasher won’t clean effectively.

Checking for Clogs: Inspect the spray arms for clogs. Food particles and mineral deposits can block the spray arm holes, reducing water pressure. Use a toothpick, wire, or small brush to clear any blockages.
Removing and Cleaning Spray Arms: Most spray arms can be easily removed for cleaning. Refer to your dishwasher’s manual for instructions on how to remove them. Once removed, soak the spray arms in warm, soapy water to loosen any stubborn debris.
Checking for Damage: Inspect the spray arms for cracks or damage. Damaged spray arms can leak water or fail to rotate properly. If you find any damage, replace the spray arms.

Food Particles and Filters

Dishwashers rely on filters to trap food particles and prevent them from recirculating during the wash cycle. If the filter is clogged, food particles will be redistributed onto your dishes.

Locating the Filter: The filter is usually located at the bottom of the dishwasher. Refer to your dishwasher’s manual for its exact location.
Cleaning the Filter: Remove the filter and rinse it thoroughly under running water. Use a brush to remove any stubborn debris. Some filters can be disassembled for more thorough cleaning.
Frequency of Cleaning: Clean the filter regularly, ideally every one to three months, depending on how often you use your dishwasher and how dirty your dishes are. A clean filter is essential for proper dishwasher performance.
Checking the Drain: Ensure the drain is clear of any food or debris that may be causing blockages.

Loading the Dishwasher Incorrectly

Improperly loading your dishwasher can prevent water and detergent from reaching all the dishes, resulting in poor cleaning. Overcrowding the dishwasher can also block the spray arms, reducing their effectiveness.

Spacing Dishes Properly: Make sure dishes are spaced apart so that water and detergent can reach all surfaces. Avoid nesting dishes together, as this will prevent them from being cleaned properly.
Facing Dishes Inward: Face the dirty surfaces of dishes towards the center of the dishwasher, where the spray arms are located.
Avoiding Overcrowding: Don’t overcrowd the dishwasher. Overcrowding can block the spray arms and prevent water from reaching all the dishes.
Positioning Large Items Carefully: Place large items like pots and pans along the sides and back of the dishwasher, where they won’t block the spray arms. Make sure they don’t obstruct the detergent dispenser or the water inlet.
Checking the Top Rack: Ensure items in the top rack are not obstructing the spray arms. Taller items may need to be placed in the lower rack.

Water Pressure Issues

Low water pressure can prevent the dishwasher from cleaning effectively. The dishwasher needs sufficient water pressure to properly spray water and detergent onto the dishes.

Checking Water Pressure: Check the water pressure in your kitchen sink. If the water pressure is low in the sink, it may also be low in the dishwasher.
Contacting a Plumber: If you suspect a water pressure problem, contact a plumber to investigate. Low water pressure can be caused by a variety of factors, such as a faulty pressure regulator or clogged pipes.
Checking the Water Inlet Valve: The water inlet valve controls the flow of water into the dishwasher. If the valve is faulty, it may not be allowing enough water into the dishwasher. A professional can inspect the water inlet valve.

Hard Water Problems

Hard water contains high levels of minerals like calcium and magnesium, which can interfere with the cleaning process. Hard water can also leave spots and film on your dishes.

Using a Rinse Aid: Rinse aid helps to reduce surface tension, allowing water to sheet off the dishes and prevent spots and film. Use a rinse aid regularly, especially if you have hard water.
Using More Detergent: Hard water requires more detergent than soft water. Increase the amount of detergent you use, following the instructions on the detergent packaging.
Installing a Water Softener: If you have very hard water, consider installing a water softener. A water softener will remove minerals from the water, improving the effectiveness of your dishwasher and other appliances.
Dishwasher Salt: Some dishwashers have a compartment for dishwasher salt, which helps to soften the water. Check your dishwasher’s manual to see if it requires dishwasher salt.

Malfunctioning Components

If you’ve tried all the above steps and your dishwasher is still not cleaning properly, there may be a problem with one of its components. These issues often require professional repair.

Heating Element: The heating element is responsible for heating the water in the dishwasher. If the heating element is faulty, the water won’t get hot enough to clean effectively.
Circulation Pump: The circulation pump circulates water throughout the dishwasher. If the pump is faulty, the water won’t be sprayed onto the dishes with enough force.
Timer or Control Board: The timer or control board controls the timing and sequencing of the dishwasher’s cycles. If the timer or control board is faulty, the dishwasher may not be running the cycles properly.
Float Switch: The float switch prevents the dishwasher from overfilling. If the float switch is stuck or faulty, it may prevent the dishwasher from filling with enough water.

Step-by-Step Troubleshooting Guide

Here’s a detailed troubleshooting guide to help you diagnose and fix your dishwasher cleaning problems:

Check the Water Temperature: Run the hot water tap in your kitchen sink until the water is hot. Then, test the water temperature with a thermometer. It should be at least 120 degrees Fahrenheit. Adjust your water heater if necessary.
Inspect the Spray Arms: Check the spray arms for clogs. Remove the spray arms and clean them thoroughly. Make sure they are rotating freely.
Clean the Filter: Remove the filter and clean it thoroughly. Make sure it is properly installed.
Check the Detergent: Make sure you are using the right type and amount of detergent. Store your detergent in a cool, dry place.
Load the Dishwasher Properly: Make sure dishes are spaced apart and facing inward. Avoid overcrowding the dishwasher.
Use Rinse Aid: Add rinse aid to the dispenser.
Run a Cleaning Cycle: Run a cleaning cycle with a dishwasher cleaner. This will help to remove any buildup of grease and grime inside the dishwasher.
Check the Water Pressure: Ensure you have adequate water pressure.

If you’ve followed all these steps and your dishwasher is still not cleaning properly, it’s time to call a qualified appliance repair technician. They can diagnose and repair any malfunctioning components.

Preventative Maintenance

Preventative maintenance can help to keep your dishwasher running smoothly and prevent cleaning problems.

Regular Cleaning: Clean your dishwasher regularly, at least once a month. Run a cleaning cycle with a dishwasher cleaner to remove any buildup of grease and grime.
Cleaning the Door Gasket: Clean the door gasket with a damp cloth to remove any food particles or mildew.
Inspecting the Hoses: Inspect the water supply and drain hoses for cracks or leaks. Replace them if necessary.
Proper Loading: Always load the dishwasher properly to ensure optimal cleaning performance.

By following these tips, you can keep your dishwasher running smoothly and enjoy sparkling clean dishes for years to come. Regular maintenance and timely troubleshooting are key to preventing major dishwasher problems.

Why aren’t my dishes coming out clean even after running the dishwasher?

Poorly cleaned dishes can stem from a few common issues within your dishwasher. The first, and often most overlooked, is improper loading. Overcrowding the racks prevents water and detergent from reaching all surfaces, leaving food particles behind. Additionally, ensure that spray arms aren’t blocked by tall items or utensils.

Another potential cause is inadequate water pressure. If the dishwasher isn’t receiving enough water, it cannot effectively wash away food residue. Check your water inlet valve and the water supply line for any kinks or obstructions. Insufficient hot water temperature, ideally around 120°F (49°C), can also hinder cleaning performance as detergents work best in warmer temperatures.

What are the key signs of a clogged dishwasher filter, and how does it affect cleaning?

One of the clearest indications of a clogged dishwasher filter is a noticeable build-up of food particles and debris at the bottom of the dishwasher tub. You might also observe a foul odor emanating from the appliance, even after a cleaning cycle. Dishes, particularly those on the bottom rack, may emerge with visible food remnants stubbornly clinging to their surfaces.

A clogged filter prevents the dishwasher from properly circulating clean water and effectively removing food waste. This means the dirty water is being sprayed back onto your dishes, essentially redepositing the grime you’re trying to eliminate. Regular cleaning of the filter, typically every one to three months depending on usage, is crucial to maintaining optimal cleaning performance.

How do I properly load my dishwasher to maximize cleaning efficiency?

Effective dishwasher loading is all about maximizing water and detergent access to all dish surfaces. Avoid overcrowding the racks, leaving sufficient space between items for water to circulate freely. Place larger items, such as pots and pans, along the sides and back, ensuring they don’t obstruct the spray arms’ rotation. Face heavily soiled areas towards the center of the dishwasher for better cleaning.

Position plates and bowls in the lower rack facing inwards, allowing the water jets to effectively reach their surfaces. In the upper rack, angle glasses and cups downwards to prevent water from pooling. Utensils should be placed loosely in the silverware basket, alternating forks, spoons, and knives to prevent nesting. Avoid placing items that could block the detergent dispenser.

What type of detergent is best for my dishwasher, and how much should I use?

The best type of dishwasher detergent often depends on your water hardness and the severity of food residue. Many modern detergents are formulated as pods, packs, or gels, offering convenience and pre-measured dosage. Consider using a detergent that includes enzymes for breaking down food particles and rinse aid for preventing water spots.

Using too much detergent can lead to residue build-up on dishes and inside the dishwasher, while using too little may result in inadequate cleaning. Follow the detergent manufacturer’s instructions carefully regarding the amount to use based on your dishwasher’s capacity and the hardness of your water. A little experimentation may be required to find the perfect balance for your specific needs.

How do I check and clean the spray arms in my dishwasher, and why is this important?

To check your dishwasher’s spray arms, first ensure the dishwasher is empty and disconnected from the power supply. Carefully remove the spray arms, typically by unscrewing or unclipping them. Inspect the small holes along the arms for any blockages from food particles or mineral deposits. Use a toothpick, wire, or pin to clear any obstructions you find.

Clean spray arms are essential for ensuring that water is distributed evenly throughout the dishwasher. Blocked spray arms result in uneven cleaning, leaving some dishes dirty while others are adequately washed. After cleaning, reattach the spray arms securely and test their rotation to ensure they spin freely. Regular cleaning of the spray arms helps maintain optimal cleaning performance.

What role does rinse aid play in dishwasher performance, and how should I use it?

Rinse aid is a surfactant that reduces the surface tension of water, allowing it to sheet off dishes more effectively. This prevents water droplets from drying on the dishes, minimizing water spots, streaks, and film. Rinse aid also helps to dry dishes faster, as there is less water remaining on the surfaces after the wash cycle.

To use rinse aid, simply fill the rinse aid dispenser in your dishwasher according to the manufacturer’s instructions. Most dispensers have an adjustable setting to control the amount of rinse aid released during each cycle. Start with the lowest setting and gradually increase it until you achieve satisfactory results. Monitor your dishes for streaks or spotting; if present, increase the rinse aid dosage slightly.

What should I do if my dishwasher still isn’t cleaning properly after trying these fixes?

If you’ve tried cleaning the filter and spray arms, adjusting your loading technique, using the correct detergent, and ensuring proper water pressure and temperature, and your dishwasher is still underperforming, it may indicate a more serious problem. There could be an issue with the motor, the wash impeller, or the electronic control board. These issues often require professional repair.

Consider consulting with a qualified appliance repair technician. They can diagnose the underlying problem accurately and provide appropriate solutions. Attempting to repair complex dishwasher components yourself without proper knowledge and tools can be dangerous and may void any existing warranty. Seeking professional help ensures a safe and effective resolution to the cleaning issue.

How to Fix a Dishwasher That’s Not Cleaning Dishes