Dishwasher Water Won't Drain: Common Causes and How to Fix It

A dishwasher that will not drain properly can leave standing water in the bottom of the tub, create unpleasant odors, and prevent the appliance from completing a wash cycle. Drainage problems are usually caused by clogged filters, blocked hoses, damaged pumps, or faulty drain components.

Before replacing parts, check for simple blockages and inspect the dishwasher’s drainage system. Below are the most common causes of a dishwasher not draining and the recommended solutions.

1. Dishwasher Filter Is Clogged

Most Common Solution

Why It Causes Drain Problems

The dishwasher filter collects food particles, grease, and debris to prevent them from entering the drain system. When the filter becomes clogged, water may not flow properly through the drain pump.

Common symptoms include:

Standing water at the bottom of the dishwasher
Dirty or cloudy water after a cycle
Slow draining
Bad odors

How to Clean a Dishwasher Filter

Disconnect power to the dishwasher for safety.
Remove the lower dish rack.
Locate the filter assembly at the bottom of the dishwasher tub.
Remove the filter according to the manufacturer’s instructions.
Rinse the filter under warm running water.
Remove food particles and buildup.
Clean the filter housing area.
Reinstall the filter securely.
Run a drain cycle to test operation.

Regular filter cleaning helps prevent future drainage problems.

2. Dishwasher Drain Pump

Most Common Solution

Why It Causes Drain Problems

The drain pump removes wastewater from the dishwasher during the drain cycle. If the pump becomes clogged, damaged, or fails electrically, water may remain inside the dishwasher.

Common signs of a failed drain pump:

Dishwasher finishes cycle with standing water
Humming or buzzing noise during draining
Water leaking from underneath the appliance
Drain cycle does not complete

How to Replace a Dishwasher Drain Pump

Disconnect power to the dishwasher.
Shut off the water supply.
Remove the lower access panel or toe kick panel.
Locate the drain pump at the bottom of the dishwasher.
Disconnect the electrical connector.
Remove the drain hose connected to the pump.
Remove mounting screws or locking tabs.
Remove the old drain pump.
Install the replacement drain pump.
Reconnect the hose and wiring.
Secure the access panel.
Run a test cycle to verify proper draining.

Find Dishwasher Drain Pump Parts
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3. Dishwasher Drain Hose Is Blocked or Kinked

Why It Causes Drain Problems

The drain hose carries wastewater from the dishwasher to the sink drain or garbage disposal. A clogged, kinked, or damaged hose can prevent water from leaving the dishwasher.

Possible causes:

Food buildup inside the hose
Hose bent or crushed
Loose connection
Damaged hose

How to Check or Replace a Dishwasher Drain Hose

Disconnect power to the dishwasher.
Turn off the water supply.
Locate the drain hose connection under the sink.
Check the hose for kinks or damage.
Disconnect the hose and inspect for blockages.
Replace the hose if cracks or damage are found.
Secure all connections with proper clamps.
Run a test cycle and check drainage.

4. Garbage Disposal Connection Problem

Why It Causes Drain Problems

If the dishwasher is connected to a garbage disposal, a blockage or installation issue can prevent wastewater from draining.

Common causes:

Dishwasher knockout plug was not removed during installation
Garbage disposal inlet is clogged
Drain connection is blocked

Solution:

Run the garbage disposal to clear possible blockages.
Inspect the dishwasher drain connection.
Confirm the knockout plug was removed if the disposal was recently installed.
Clean the connection area.
Run the dishwasher drain cycle.

5. Dishwasher Drain Pump Impeller Is Blocked

Why It Causes Drain Problems

The drain pump uses an impeller to push water through the drain hose. Food particles, broken glass, or other objects can block the impeller and prevent draining.

Signs of an impeller blockage:

Drain pump runs but water remains
Grinding or clicking sounds
Slow draining

Solution:

Disconnect power to the dishwasher.
Remove the filter assembly.
Access the drain pump area.
Remove any debris around the impeller.
Reassemble components.
Run a drain cycle.

If the impeller is damaged, replace the drain pump assembly.

6. Dishwasher Check Valve or Drain Valve

Why It Causes Drain Problems

The check valve prevents dirty water from flowing back into the dishwasher after draining. If the valve becomes stuck or damaged, water may remain inside the tub.

Symptoms:

Water returns after draining
Standing water at the bottom of the dishwasher
Dishwasher drains slowly

Solution:

Disconnect dishwasher power.
Locate the check valve near the drain hose connection.
Inspect the valve for debris or damage.
Clean or replace the valve if necessary.

7. Dishwasher Drain Solenoid

Why It Causes Drain Problems

Some older dishwasher models use a drain solenoid to activate the drain valve. If the solenoid fails, the dishwasher may not switch into drain mode.

Symptoms:

Dishwasher fills and washes normally but will not drain
Clicking sounds during drain cycle
Water remains after cycle completion

How to Replace a Dishwasher Drain Solenoid

Disconnect power from the dishwasher.
Remove the lower access panel.
Locate the drain solenoid near the pump assembly.
Disconnect electrical wiring.
Remove mounting hardware.
Install the replacement solenoid.
Reconnect wiring.
Test dishwasher operation.

8. Dishwasher Air Gap Is Clogged

Why It Causes Drain Problems

Some dishwasher installations use an air gap device on the countertop to prevent dirty water from flowing back into the dishwasher. A clogged air gap can restrict drainage.

Solution:

Remove the air gap cover.
Inspect for food debris or buildup.
Clean the air gap components.
Reassemble and test drainage.

9. Dishwasher Circulation Pump Problem

Why It Causes Drain Problems

Although the circulation pump is mainly responsible for washing, damage to the pump assembly or internal seals may affect water movement and drainage.

Possible symptoms:

Water remains in the tub
Unusual pump noises
Poor cleaning performance

Inspect the pump assembly and replace damaged components if needed.

10. Dishwasher Control Board

Why It Causes Drain Problems

The control board manages the dishwasher’s drain cycle and sends power to the drain pump. If the control board fails, the dishwasher may not activate the pump correctly.

Signs of a control board issue:

Drain pump does not receive power
Dishwasher stops during cycles
Multiple functions fail

Before replacing the control board, test the drain pump and wiring first.

11. Dishwasher Drain Hose Is Installed Incorrectly

Why It Causes Drain Problems

A properly installed drain hose requires a high loop or air gap to prevent wastewater from flowing back into the dishwasher.

Incorrect installation may cause:

Water returning to the dishwasher
Dirty water buildup
Poor draining

Solution:

Check the drain hose routing under the sink.
Ensure the hose has a proper high loop.
Adjust the hose position if necessary.
Test dishwasher drainage.

Preventing Dishwasher Drain Problems

To help prevent future drainage issues:

Clean the dishwasher filter regularly.
Remove large food particles before loading dishes.
Avoid putting grease or heavy debris into the dishwasher.
Inspect the drain hose periodically.
Clean the garbage disposal connection.
Run dishwasher cleaner occasionally to remove buildup.

Find the Correct Dishwasher Replacement Part

A dishwasher that will not drain is commonly caused by a clogged filter, blocked drain hose, failed drain pump, or damaged drainage component.

Before ordering replacement parts, always verify your dishwasher model number to ensure the correct fit and compatibility.

At Authentic Appliance Parts, we provide quality dishwasher replacement parts and repair resources to help you diagnose drainage problems and complete repairs with confidence.