Troubleshooting A Dishwasher Not Draining: Do I Need A Pro?

Troubleshooting A Dishwasher Not Draining: Do I Need A Pro?

Table of Contents

Common Causes of Dishwasher Drainage Problems

Have you ever wondered why your dishwasher is not draining properly? 

A malfunctioning dishwasher can be a major inconvenience, disrupting your daily routine and potentially leading to a pile-up of dirty dishes. 

Understanding the common causes of drainage issues can empower you to troubleshoot and potentially resolve the problem yourself, saving you time and money on professional repairs.


A plumber is removing the dirty food residue filter from the dishwasher.
Photo from iStock – Credit: ronstik

Clogged Filters

Identifying a Clogged Filter

A common culprit for a dishwasher not draining is a clogged filter. 

Filters are designed to catch food particles and debris, preventing them from entering the drain and causing blockages. 

Over time, these particles can accumulate, leading to a clogged filter, which hinders the dishwasher’s ability to drain water effectively.


Cleaning and Maintaining Filters

Regular cleaning of the filter is crucial to ensure efficient drainage and prolong the life of your dishwasher. 

Here’s how you can clean the filter:

Remove the lower dish rack to access the filter. The filter is usually located at the bottom of the dishwasher, beneath the spray arm.

Twist and lift the filter out of the dishwasher. Most filters can be easily removed by twisting them counterclockwise and lifting them out.

Rinse the filter under running water, using a soft brush to remove stubborn debris. This helps to clear out any accumulated food particles and other debris that may be causing the blockage.

Maintaining a clean filter is essential for the smooth operation of your dishwasher. 

Regular cleaning ensures that water can flow freely through the drainage system, preventing backups and potential damage to the appliance. 

By incorporating this simple maintenance task into your routine, you can avoid many common drainage issues and keep your dishwasher running efficiently.


Drain Hose Issues

Checking for Kinks

A kinked drain hose can significantly restrict water flow, leading to drainage issues. 

To troubleshoot this problem, carefully inspect the hose for any bends or obstructions. 

If you find a kink, gently straighten it to restore proper water flow. 

Ensuring the hose is positioned correctly can prevent it from bending again in the future.


Clearing Blockages

If the drain hose is not kinked but the dishwasher is still not draining, it may be clogged with debris. Here’s how to clear the blockage:

  1. Disconnect the hose from the dishwasher and the sink drain. Ensure the dishwasher is unplugged to avoid any electrical hazards.
  2. Blow air through the hose to check for clogs. This can help identify if there are any blockages preventing water from flowing through.
  3. Use a coat hanger or similar tool to remove any obstructions you find. Straighten the coat hanger and carefully insert it into the hose to push out or pull out any debris.

By regularly checking and maintaining the drain hose, you can prevent many common drainage issues and ensure your dishwasher continues to operate efficiently​


Garbage Disposal Problems

Ensuring Proper Installation

If your dishwasher drain hose is connected to a garbage disposal, it’s essential to ensure the disposal is installed correctly. 

An improperly installed garbage disposal can cause drainage issues by not allowing water to flow properly from the dishwasher. 

One common mistake is leaving the knockout plug inside the disposal unit. 

This plug blocks the water flow if not removed after installation. 

To avoid this problem, always check and remove the knockout plug to ensure a clear path for drainage​.


Regular Maintenance Tips

Regular maintenance of your garbage disposal is crucial to prevent clogs and ensure smooth operation. Here are some tips:


Run the garbage disposal regularly

Frequent use of the disposal helps keep it clear of food particles and debris that can cause clogs. 

Running it with cold water for a few minutes after each use can help flush out any remaining particles​.


Avoid disposing of large chunks of food or fibrous materials

Items such as potato peels, celery, and other fibrous foods can wrap around the blades and clog the disposal. Instead, dispose of these materials in the trash or compost.


Use disposal-friendly cleaners

Occasionally, clean the disposal with a mixture of baking soda and vinegar followed by hot water. 

This helps to break down grease and remove odors without damaging the unit.

By following these maintenance tips, you can keep your garbage disposal in good working order, which in turn helps maintain the proper function of your dishwasher’s drainage system


Air Gap Blockages

The function of an Air Gap

An air gap is a vital component of your drainage system, designed to prevent dirty water from back flowing from the sink into the dishwasher. 

It’s typically a small cylindrical device located near the sink faucet. 

Over time, the air gap can become clogged with debris, which can hinder proper drainage and cause water to back up into the dishwasher.


Cleaning an Air Gap

To ensure your air gap functions correctly, it’s essential to clean it regularly. 

Here’s a step-by-step guide to cleaning the air gap:


Remove the cover of the air gap:

Carefully lift off the cover of the air gap. 

This cover is usually a metal or plastic cap that can be pulled off or unscrewed, depending on the model​​.


Clear any debris from the inside:

Use a small brush, toothpick, or a similar tool to remove any accumulated debris inside the air gap. 

Pay special attention to the small tubes and passages where blockages are likely to form​.


Rinse thoroughly to ensure no blockages remain:

After clearing the debris, rinse the air gap thoroughly with water. 

Ensure that water flows freely through the air gap to verify that all blockages are removed.

Maintaining a clean air gap is essential for the efficient operation of your dishwasher. 

Regular cleaning prevents debris buildup that can lead to drainage issues and ensures that the system works as intended to keep dirty water from contaminating your dishwasher


Faulty Dishwasher Parts

Inspecting the Drain Pump

The drain pump plays a crucial role in expelling water from the dishwasher at the end of a wash cycle. 

If this pump is faulty, water may remain pooled at the bottom of the dishwasher, leading to potential malfunctions and unpleasant odors. 

To ensure the drain pump is working correctly, follow these steps:


Check for signs of damage or wear:

Visually inspect the drain pump for any obvious signs of damage such as cracks, wear, or burn marks. 

If you notice any of these issues, the pump may need to be replaced.


Listen for unusual noises:

When the dishwasher runs, listen for any unusual sounds coming from the pump area. 

Grinding or humming noises can indicate that the pump is not functioning properly.


Test the pump:

If accessible, test the pump by running a cycle and observing if the water is being expelled correctly. 

You can also use a multimeter to check the electrical continuity of the pump, ensuring it’s receiving the correct voltage.


Replace if necessary:

If the pump shows signs of damage or fails the continuity test, it should be replaced. 

Consult your dishwasher’s manual for the correct part number and installation instructions.


Checking the Float Switch

The float switch is a safety device that monitors the water level inside the dishwasher. 

It prevents the dishwasher from overfilling by shutting off the water supply when the correct level is reached. 

A malfunctioning float switch can cause the dishwasher to either not fill with water or not drain properly. 

Here’s how to check and maintain the float switch:

  1. Locate the float switch: The float switch is usually located at the bottom of the dishwasher, often near the front. It typically looks like a small plastic cylinder or dome.
  2. Ensure it moves freely: Gently lift and lower the float switch to make sure it moves up and down without resistance. If it’s stuck or obstructed by debris, it can’t accurately monitor the water level.
  3. Clean around the float: Debris and food particles can accumulate around the float switch, causing it to malfunction. Clean the area around the float switch with a damp cloth or brush to remove any obstructions.
  4. Test the float switch: During a wash cycle, observe if the float switch rises and falls with the water level. You can also use a multimeter to test the switch for electrical continuity to ensure it is functioning correctly.

By regularly inspecting and maintaining the drain pump and float switch, you can prevent many common dishwasher drainage issues.


DIY Troubleshooting Steps

When your dishwasher is not draining, following a structured troubleshooting process can help identify and resolve the issue. 

Here are some effective DIY steps to take before calling a professional.


Preliminary Checks

Ensuring the Cycle is Complete

Before diving into more detailed troubleshooting, ensure that the cycle is fully complete. 

Sometimes, the dishwasher may seem to be not draining because the cycle was interrupted or stopped prematurely.


Removing Standing Water

If there is standing water in the bottom of the dishwasher, you can remove it manually. 

Use a cup or a small container to scoop out the water, and then use a towel to soak up any remaining water. 

This will allow you to inspect and clean other components more easily.


Step-by-Step Troubleshooting

Cleaning the Filter

A clogged filter is a common cause of drainage problems. To clean it:

  1. Remove the bottom dish rack to access the filter.
  2. Take out the filter by twisting it counterclockwise.
  3. Rinse the filter under running water, using a soft brush to remove any debris.


Inspecting and Cleaning the Drain Hose

The drain hose can sometimes get blocked by food particles or debris. To inspect and clean the hose:

  1. Disconnect the power to the dishwasher.
  2. Locate the drain hose, which is typically connected to the sink or garbage disposal.
  3. Check for kinks or bends in the hose and straighten them out.
  4. Disconnect the hose and use a long flexible brush or a straightened coat hanger to remove any blockages.


Clearing the Garbage Disposal and Air Gap

If your dishwasher is connected to a garbage disposal, make sure it is clear of food waste. 

Turn on the disposal to clear any blockages. 

Additionally, check the air gap (a small cylindrical device near the sink faucet) for any clogs:

  1. Remove the cover of the air gap.
  2. Clean out any debris using a brush or toothpick.


When to Use DIY Solutions

Minor Clogs and Simple Fixes

DIY solutions are effective for minor clogs and simple issues like a dirty filter or a kinked hose. 

Regular maintenance can prevent these problems from recurring.


Regular Maintenance Practices

Perform regular maintenance to keep your dishwasher in top condition. This includes:

  • Rinsing dishes before loading them to prevent food particles from clogging the system.
  • Running a cleaning cycle with vinegar or a dishwasher cleaner monthly to remove build-up.
  • Inspecting and cleaning the filter and drain hose regularly.


When to Call a Professional

Knowing when to call a plumber can save you time, frustration, and potential damage to your dishwasher and home.


Persistent Issues

Recurring Drainage Problems

If you’ve attempted all the DIY fixes and your dishwasher still won’t drain properly, it’s likely that the issue is more complex. 

Persistent drainage problems can indicate a deeper issue within the appliance that requires professional diagnosis and repair.


Faulty Components Beyond DIY Repair

Certain components of your dishwasher, such as the drain pump, solenoid, or control board, may malfunction and are beyond the scope of typical DIY repairs. 

These parts often require specialized tools and knowledge to replace safely and correctly. 

Signs that these parts may be faulty include:

  • The drain pump is not making any noise or making unusual noises.
  • The solenoid valve is not opening or closing properly.
  • Electrical issues with the control board affect the dishwasher’s operations.


Benefits of Professional Services

Expertise and Experience

Professional plumbers have the expertise and experience to quickly diagnose and repair issues that might be confusing or challenging for a homeowner. 

They can identify problems that may not be immediately obvious and offer solutions that ensure long-term reliability.


Safety and Warranty Considerations

Hiring a professional ensures that repairs are done safely, especially when dealing with electrical components and water lines. 

Additionally, professional repairs are often covered by warranties, providing you with peace of mind and protection against future issues.


Plumbing Maintenance Tips for Homeowners.
Photo from iStock – Credit: grapestock

Preventative Maintenance Tips

Preventative maintenance can help avoid drainage issues and extend the life of your dishwasher. 

Here are some tips to keep your appliance running smoothly.


Regular Cleaning

Cleaning Schedules for Filters and Hoses:

Filter cleaning: Clean the dishwasher filter every month to prevent buildup. Simply remove it, rinse it under warm water, and scrub away any debris.

Hose inspection: Check the drain hose periodically for kinks or clogs. Ensure it is properly connected and clear of obstructions.


Using Cleaning Agents Safely

Use dishwasher-safe cleaning agents to prevent buildup inside your machine. 

Run a cleaning cycle with a specialized dishwasher cleaner or a mixture of vinegar and baking soda every few months.



Proper maintenance and timely troubleshooting are key to keeping your dishwasher running efficiently. 

By understanding common drainage issues and knowing when to perform DIY fixes versus calling a professional, you can prevent many problems from occurring.

Regular maintenance, such as cleaning filters and inspecting hoses, can prevent most minor clogs and ensure your dishwasher operates smoothly. 

However, when you face persistent issues or faulty components, don’t hesitate to contact a professional like bluefrog Plumbing + Drain West Houston

Their expertise can save you time, money, and the hassle of dealing with a non-functional dishwasher.

Whether you’re in Katy, TX, or Sugar Land, TX, professional help is just a call away. 

Regular check-ups and maintenance from a trusted service provider can keep your dishwasher in top condition and provide peace of mind.



  1. Why is my dishwasher not draining properly?

    Your dishwasher might not be draining due to a clogged filter, a kinked drain hose, a blocked air gap, or issues with the garbage disposal or internal components like the drain pump.


  1. How often should I clean my dishwasher filter?

    It’s recommended to clean your dishwasher filter once a month to prevent food particles and debris from causing blockages.


  1. Can I use vinegar and baking soda to clean my dishwasher?

    Yes, a mixture of vinegar and baking soda can be an effective way to clean your dishwasher and prevent clogs. Pour the mixture into the bottom of the dishwasher, let it sit for 15 minutes, then run a hot water cycle.


  1. When should I call a professional for my dishwasher?

    Call a professional if you’ve tried all DIY troubleshooting steps and the problem persists if there are faulty components like the drain pump or float switch, or if there are recurring drainage issues.


  1. What can I do to prevent my dishwasher from not draining?

    Regularly clean the filter, inspect and clean the drain hose, avoid overloading the dishwasher, and ensure the garbage disposal and air gap are clear of debris. Routine maintenance and proper usage can help prevent drainage issues.


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  • Memorial City
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  • Spring Branch West
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