Dishwasher Not Draining Well: Troubleshooting Guide
Quick answer
First, check for clogs in the drain filter and hose. If they're clear, inspect the drain pump for blockages. If these steps don't resolve the issue, you may need to replace the drain pump or call a professional.
Confirm the symptom
- Dishwasher leaves standing water at the bottom.
- Dishes are not getting clean due to poor drainage.
- Dishwasher makes unusual noises during the drain cycle.
- Drain cycle takes longer than usual.
- Water backs up into the sink when the dishwasher is running.
Tools and prep
- screwdriver set
- bucket
- towel
- flashlight — to see in dark spaces
- plumber's snake
- work gloves — to protect hands from sharp objects
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Prep & safety
- Ensure the dishwasher is unplugged or the circuit breaker is turned off for safety.
- Clear the area around the dishwasher for easy access.
- Gather your tools and have a towel ready to clean up any water.
- Check the dishwasher manual for specific instructions related to your model.
Step-by-step troubleshooting
Check the Drain Filter
Do: Locate the drain filter at the back of the dishwasher's bottom interior. Remove it by twisting it counterclockwise.
Observe: Look for food particles, debris, or other blockages.
Means: If the filter is clogged, clean it thoroughly under running water.
Next: Reassemble and test the dishwasher.
Inspect the Drain Hose
Do: Disconnect the drain hose from the dishwasher and the sink drain or garbage disposal.
Observe: Check for kinks, clogs, or damage in the hose.
Means: Straighten any kinks and clear any clogs. Replace the hose if it's damaged.
Next: Reconnect the hose and test the dishwasher.
Examine the Air Gap
Do: Locate the air gap on the kitchen counter or sink. Remove the cap and check for blockages.
Observe: Look for food particles or debris inside the air gap.
Means: Clear any blockages with a plumber's snake or a small brush.
Next: Reassemble the air gap and test the dishwasher.
Check the Drain Pump
Do: Access the drain pump, usually located at the bottom of the dishwasher.
Observe: Look for blockages or damage in the pump.
Means: Clear any blockages. If the pump is damaged, it may need replacement.
Next: Test the dishwasher to see if the issue is resolved.
Inspect the Check Valve
Do: Locate the check valve, typically near the drain pump.
Observe: Check for damage or blockages in the check valve.
Means: Replace the check valve if it's damaged or not functioning properly.
Next: Test the dishwasher to ensure proper drainage.
Examine the Drain Impeller
Do: Access the drain impeller, usually part of the drain pump assembly.
Observe: Check for damage or blockages in the impeller.
Means: Clear any blockages. If the impeller is damaged, it may need replacement.
Next: Test the dishwasher to see if the issue is resolved.
Check the Motor and Control Board
Do: Inspect the dishwasher's motor and control board for any signs of failure.
Observe: Look for burnt smells, unusual noises, or visible damage.
Means: If the motor or control board is faulty, it may need professional repair or replacement.
Next: Consider calling a professional if these components are damaged.
Common causes table
| Cause | Why | Likelihood | Difficulty | Part often needed |
|---|---|---|---|---|
| Clogged Drain Filter | Food particles and debris can accumulate and block the filter. | High | Easy | None |
| Kinked or Clogged Drain Hose | The hose can become kinked or clogged with debris. | Medium | Medium | Drain hose |
| Blocked Air Gap | Food particles can block the air gap, preventing proper drainage. | Medium | Easy | None |
| Faulty Drain Pump | The drain pump can fail or become clogged, preventing water from draining. | Medium | Medium | Drain pump |
| Damaged Check Valve | The check valve can fail, allowing water to flow back into the dishwasher. | Low | Medium | Check valve |
| Faulty Drain Impeller | The impeller can become damaged or clogged, preventing proper drainage. | Low | Medium | Drain impeller |
| Motor or Control Board Failure | The motor or control board can fail, affecting the dishwasher's operation. | Low | High | Motor or control board |
Parts matching
When replacing parts, ensure they match your dishwasher's make and model. Check the user manual or the manufacturer's website for specific part numbers.
- Drain pump: Match the model number and voltage (e.g., Model XYZ, 120V).
- Drain hose: Match the length and diameter (e.g., 6-foot, 1/2-inch hose).
- Check valve: Match the dishwasher's make and model (e.g., Brand ABC, Model 123).
- Drain impeller: Match the dishwasher's make and model (e.g., Brand XYZ, Model 456).
- Motor: Match the horsepower and voltage (e.g., 1/2 HP, 120V).
- Control board: Match the dishwasher's make and model (e.g., Brand DEF, Model 789).
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 suspect a problem with the motor or control board.
- If you're not comfortable performing the repairs yourself.
- If the dishwasher is under warranty.
- If the dishwasher is leaking water.
- If there are unusual noises or smells coming from the dishwasher.
FAQ
Why is my dishwasher leaving standing water at the bottom?
Standing water in the dishwasher can be caused by a clogged drain filter, kinked drain hose, or a faulty drain pump. Check these components and clear any blockages.
How do I clean the dishwasher drain filter?
Remove the drain filter by twisting it counterclockwise. Clean it thoroughly under running water to remove any food particles or debris. Reassemble and test the dishwasher.
What should I do if the drain hose is kinked?
Straighten the kinked drain hose and ensure it's properly connected to the dishwasher and the sink drain or garbage disposal. Replace the hose if it's damaged.
How do I know if the drain pump is faulty?
If the drain pump is making unusual noises, not running, or failing to drain water, it may be faulty. Inspect the pump for blockages or damage and replace it if necessary.
What is the air gap in a dishwasher?
The air gap is a small device, usually located on the kitchen counter or sink, that prevents water from flowing back into the dishwasher. It can become clogged with food particles, preventing proper drainage.
How often should I clean the dishwasher drain filter?
It's a good idea to clean the dishwasher drain filter every 3-6 months to prevent clogs and ensure proper drainage. Regular maintenance can help keep your dishwasher running smoothly.