Why Won't My Dishwasher Drain (Troubleshooting Guide)

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Quick answer
Confirm the symptom
Tools and prep
Step-by-step troubleshooting
Common causes table
Parts matching
When to call a pro
FAQ
Related guides

Quick answer

Your dishwasher may not drain due to a clogged filter, blocked drain hose, or a faulty pump. Turn off the power, check for blockages, and clear any debris to restore drainage.

Confirm the symptom

Standing water remains after a cycle ends
Dishes are wet or soapy after a cycle
Gurgling or bubbling sounds during draining

Tools and prep

Screwdriver (flathead or Phillips, depending on model)
Flashlight
Rubber gloves
Bucket or towel
Plumber's snake or wire hanger (straightened)
Clean cloth or paper towels
Turn off power at circuit breaker for safety

Step-by-step troubleshooting

Check the Dishwasher Filter
Do: Locate and remove the filter at the bottom of the dishwasher tub.
Observe: Look for food particles, grease, or debris blocking the filter.
Means: A clogged filter prevents proper drainage.
Next: Clean the filter thoroughly and reinstall it.
Inspect the Drain Hose
Do: Access the drain hose under the sink or behind the dishwasher.
Observe: Check for kinks, clogs, or disconnections in the hose.
Means: A blocked or misaligned hose stops water from draining.
Next: Straighten the hose, clear any clogs, and ensure it connects securely to the drain.
Clear the Air Gap (if applicable)
Do: Locate the air gap on the countertop (if your model has one) and remove the cap.
Observe: Look for debris or blockages inside the air gap chamber.
Means: A clogged air gap can prevent drainage.
Next: Clean the air gap and reassemble it.
Test the Drain Pump
Do: Listen for the drain pump to activate during the drain cycle.
Observe: If the pump doesn't run or makes unusual noises, it may be faulty.
Means: A malfunctioning pump can't push water out.
Next: Check for blockages in the pump or consider replacing it.
Check for a Faulty Float Switch
Do: Look at the float switch near the bottom of the dishwasher.
Observe: If the float is stuck or damaged, it may prevent the pump from operating.
Means: A faulty float switch stops the pump from draining water.
Next: Clean or replace the float switch if necessary.
Inspect the Drain Valve
Do: Access the drain valve (usually at the bottom of the dishwasher).
Observe: Check for debris or if the valve is stuck closed.
Means: A blocked or faulty valve prevents water from exiting.
Next: Clean the valve or replace it if damaged.
Run a Diagnostic Cycle
Do: Refer to your dishwasher's manual to initiate a diagnostic or drain-only cycle.
Observe: Watch for error codes or unusual behavior during the cycle.
Means: Diagnostic cycles can identify specific issues with the drainage system.
Next: Address any identified issues based on the diagnostic results.

Common causes

Cause	Likelihood	Difficulty	Part often needed
Clogged Filter Food particles and debris block water flow.	Common	Easy	Dishwasher filter (if damaged)
Blocked Drain Hose Kinks, clogs, or improper connections prevent drainage.	Common	Easy–Medium	None (usually just cleaning)
Clogged Air Gap Debris in the air gap chamber blocks water flow.	Sometimes	Easy	None (usually just cleaning)
Faulty Drain Pump Pump motor or impeller failure stops water from draining.	Sometimes	Medium–Hard	Drain pump assembly
Stuck or Faulty Float Switch The float switch prevents the pump from activating if stuck.	Sometimes	Medium	Float switch assembly
Blocked Drain Valve Debris or a faulty valve prevents water from exiting.	Sometimes	Medium	Drain valve assembly
Control Board Issue A malfunctioning control board may fail to activate the drain pump.	Rare	Hard	Control board

Parts matching

If you need to replace parts, match these common components to your dishwasher model:

Dishwasher filter (model-specific)
Drain pump assembly (check compatibility)
Float switch assembly
Drain valve assembly
Air gap unit (if applicable)

Consult your dishwasher’s manual for part numbers and compatibility details before purchasing replacements.

When to call a professional

Standing water persists after multiple cleaning attempts
Drain pump makes loud or grinding noises
You suspect a control board or electrical issue
You're unsure about accessing internal components
Drainage problems return frequently after DIY fixes

FAQ

How often should I clean my dishwasher filter?

Clean the filter every 1–2 months to prevent clogs and maintain performance.

Can I use a drain cleaner on my dishwasher?

Avoid chemical drain cleaners, as they can damage internal components. Use hot water and a brush instead.

Why does my dishwasher smell bad if it won't drain?

Standing water and trapped debris cause mold and mildew, leading to unpleasant odors. Clearing the blockage should resolve the smell.

Is it normal for my dishwasher to make gurgling sounds during draining?

Occasional gurgling is normal, but constant or loud noises may indicate a blockage or pump issue.

Can a clogged garbage disposal affect my dishwasher drainage?

Yes, if the dishwasher connects to the garbage disposal, a clogged disposal can block drainage. Check both units for blockages.