Dishwasher Not Draining But Pump Running: Troubleshooting Guide
Quick answer
Check for clogs in the drain hose or air gap. Ensure the drain filter is clean. If these are clear, inspect the drain valve and motor for issues. If unsure, consult a professional.
Confirm the symptom
- Dishwasher leaves standing water after cycle
- Drain pump makes noise but water doesn't drain
- Cycle completes but dishes aren't clean due to poor drainage
- Error code related to drainage on display
- Water backing up into the sink
Tools and prep
- screwdriver flathead — for removing dishwasher panels
- screwdriver phillips — for removing dishwasher panels
- shop vac — for removing excess water
- bucket — for collecting water
- towel — for drying and cleaning
- flashlight — for better visibility
- gloves latex — for handling dirty water
- drain snake — for clearing clogs
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Prep & safety
- Ensure the dishwasher is turned off and unplugged from the power source.
- Allow the dishwasher to cool down if it was recently in use.
- Place towels or a bucket underneath the dishwasher to catch any water.
- Clear the area around the dishwasher for easy access.
Step-by-step troubleshooting
Check the Drain Filter
Do: Locate the drain filter at the back of the dishwasher's bottom interior.
Observe: Remove the filter and check for debris or blockages.
Means: Clean the filter thoroughly with warm soapy water.
Next: Reassemble and test the dishwasher.
Inspect the Drain Hose
Do: Disconnect the drain hose from the sink's drainpipe or garbage disposal.
Observe: Check for kinks, clogs, or blockages in the hose.
Means: Straighten any kinks and clear any debris.
Next: Reconnect the hose and test the dishwasher.
Check the Air Gap
Do: Locate the air gap on the kitchen counter or sink.
Observe: Remove the cap and check for blockages.
Means: Clear any debris using a small brush or toothpick.
Next: Reassemble and test the dishwasher.
Examine the Drain Valve
Do: Access the drain valve, usually located at the bottom of the dishwasher.
Observe: Check for any blockages or damage.
Means: Clean or replace the valve if necessary.
Next: Reassemble and test the dishwasher.
Inspect the Drain Pump
Do: Locate the drain pump, typically at the bottom of the dishwasher.
Observe: Check for any obstructions or damage.
Means: Clear any debris and ensure the pump spins freely.
Next: Reassemble and test the dishwasher.
Test the Drain Motor
Do: Access the drain motor, usually near the drain pump.
Observe: Check for any signs of failure or burnout.
Means: Listen for unusual noises and test the motor's operation.
Next: Replace the motor if necessary.
Check the Float Switch
Do: Locate the float switch inside the dishwasher.
Observe: Ensure it moves freely and is not stuck.
Means: Clean the float switch and test its operation.
Next: Reassemble and test the dishwasher.
Inspect the Control Board
Do: Access the control board, usually located behind the dishwasher's control panel.
Observe: Check for any signs of damage or burnout.
Means: Test the control board for proper functioning.
Next: Replace the control board if necessary.
Common causes table
| Cause | Why | Likelihood | Difficulty | Part often needed |
|---|---|---|---|---|
| Clogged Drain Filter | Food particles and debris can accumulate, blocking water flow. | High | Easy | None |
| Kinked or Clogged Drain Hose | The hose can become kinked or blocked, preventing proper drainage. | Medium | Easy | New drain hose |
| Blocked Air Gap | Debris can accumulate in the air gap, causing a backup. | Medium | Easy | None |
| Faulty Drain Valve | The valve can fail to open, preventing water from draining. | Medium | Moderate | Drain valve |
| Obstructed Drain Pump | Debris can block the pump, preventing it from functioning properly. | Medium | Moderate | None |
| Failed Drain Motor | The motor can burn out or fail, stopping the pump from operating. | Low | Moderate | Drain motor |
| Stuck Float Switch | The float switch can get stuck, preventing the dishwasher from draining. | Low | Easy | None |
| Faulty Control Board | The control board can malfunction, causing drainage issues. | Low | Hard | Control board |
Parts matching
When replacing parts, ensure they match your dishwasher's make and model. Check the user manual or manufacturer's website for specific part numbers.
- Drain hose: Match the length and diameter (e.g., 3/4 inch, 6 feet)
- Drain valve: Match the brand and model (e.g., Whirlpool WP8281040)
- Drain motor: Match the voltage and horsepower (e.g., 120V, 1/20 HP)
- Control board: Match the brand and model (e.g., GE WH12X10042)
Keep the old part as a reference when purchasing a new one.
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When to call a pro
- If the dishwasher is still not draining after troubleshooting
- If you're uncomfortable performing the repairs yourself
- If the dishwasher is under warranty
- If you suspect a gas leak or electrical issue
- If the dishwasher is leaking water
- If the dishwasher makes unusual noises during operation
- If you need help diagnosing the problem
FAQ
Why is my dishwasher not draining but the pump is running?
This issue can be caused by clogs in the drain filter, drain hose, or air gap. It could also be due to a faulty drain valve, obstructed drain pump, failed drain motor, stuck float switch, or a malfunctioning control board.
How do I clean the dishwasher drain filter?
Locate the drain filter at the back of the dishwasher's bottom interior. Remove it and clean it thoroughly with warm soapy water. Reassemble and test the dishwasher.
What should I do if the drain hose is kinked?
Straighten the kink in the drain hose and ensure it is properly connected to the sink's drainpipe or garbage disposal. Test the dishwasher to see if the issue is resolved.
How do I check the air gap for blockages?
Locate the air gap on the kitchen counter or sink. Remove the cap and use a small brush or toothpick to clear any debris. Reassemble and test the dishwasher.
What if the drain pump is obstructed?
Access the drain pump at the bottom of the dishwasher. Clear any debris and ensure the pump spins freely. Reassemble and test the dishwasher.
When should I replace the drain motor?
If the drain motor is making unusual noises or not functioning properly, it may need to be replaced. Ensure the new motor matches the voltage and horsepower of the old one.