Dishwasher Pump Running But Not Draining? (When the Motor Works But Water Stays)

Quick Answer: If you can hear the drain pump running but water isn’t leaving, the pump motor is fine — but something is preventing water from exiting. The most common causes are a stuck check valve, blocked drain hose, or debris wrapped around the pump impeller.

This is a frustrating but specific problem: you hear the pump humming away, but when you open the door, the water is still there. The good news is that your pump motor works. The bad news is something is blocking the water path. For replacement parts, sites like RepairClinic carry OEM components for all major brands.

Why This Happens

The drain pump creates suction to pull water out of the dishwasher. If the motor runs but water doesn’t move, one of these is happening:

Impeller is spinning but not gripping water — Damaged blades or debris interference
Water has nowhere to go — Blocked hose or check valve
Water exits then returns — Failed check valve allowing backflow
Pump runs but impeller doesn’t spin — Broken impeller shaft

Let’s diagnose which one you’re dealing with.

Step 1: Confirm the Pump Is Actually Running

First, make sure you’re hearing the drain pump and not something else:

During the drain portion of a cycle:

Put your ear near the bottom front of the dishwasher
You should hear a motor humming
The sound should be steady, not clicking or grinding

What different sounds mean:

Sound	Likely Issue
Steady hum, no drainage	Blocked path or impeller problem
Humming then stops	Pump may be overheating/cutting out
Grinding sound	Debris in pump housing
Clicking	Pump trying to start but can’t
Complete silence	Electrical failure (different problem)

If you hear steady operation but no drainage, continue with this guide.

Step 2: Check for a Blocked Drain Hose

The drain hose is the most common culprit when the pump runs but water stays.

Under your sink:

Locate the drain hose from the dishwasher
Check for obvious kinks or crushed sections
Feel along the hose for bulges (trapped debris)
Verify the connection to the disposal/drain isn’t plugged

Testing the hose:

Place a bucket under the hose connection
Disconnect the hose from the disposal or drain
Run a drain cycle
If water flows freely into the bucket, the pump and hose are fine — the blockage is at the connection point
If no water comes out, the blockage is in the hose or at the pump

Clearing a blocked hose:

Disconnect both ends of the hose
Flush with water from a garden hose
Use a long flexible brush or straightened hanger
Replace if the hose is damaged or heavily clogged

For proper hose installation and more details, see our drain hose guide.

Step 3: Inspect the Check Valve

The check valve is a one-way door that lets water out but prevents backflow. If it’s stuck closed, water can’t exit even with the pump running.

Where to find it:

In the drain hose (usually near the disposal connection)
At the pump outlet inside the dishwasher
Built into the pump assembly (some models)

Signs of check valve failure:

Pump runs but absolutely no water movement
Water drains then slowly returns
Gurgling sounds when the sink drains

Checking the valve:

Locate the check valve (consult your manual if needed)
Remove and inspect for debris
The flapper should swing freely in one direction only
If stuck or damaged, replace it ($15-30 part)

If the valve is stuck closed:

Debris like glass, bones, or labels can jam it shut
Soap buildup can gum it in place
Clean thoroughly or replace

Step 4: Check for Impeller Problems

The impeller is the spinning part inside the pump that moves water. If it’s damaged or obstructed, the motor runs but doesn’t pump effectively.

Accessing the impeller:

Remove the dishwasher filters
Look into the drain pump area in the sump
You may need to remove a cover plate
The impeller should be visible

What to look for:

Debris wrapped around the impeller shaft (hair, twist ties, label backing)
Broken impeller blades (cracks or missing pieces)
The impeller should spin freely by hand

If debris is wrapped around the shaft:

Use needle-nose pliers to remove material
Check that the impeller spins smoothly after
Run a test cycle

If impeller blades are damaged: The pump likely needs replacement. A broken impeller spins but doesn’t move water effectively.

Step 5: Verify the Garbage Disposal Path

If your dishwasher drains through the garbage disposal, problems there prevent drainage:

Check for:

Knockout plug not removed — New disposals come with a solid plug that must be knocked out
Disposal clogged with food — Run the disposal thoroughly
Disposal drain blockage — If the disposal itself doesn’t drain, neither will the dishwasher

Testing the disposal connection: Shine a flashlight into the disposal and look for the dishwasher inlet (small opening on the side wall). Make sure it’s clear.

Step 6: Check Air Gap (If You Have One)

The air gap prevents backflow but can become clogged and block drainage.

Signs of air gap blockage:

Water shoots out of the air gap during drain cycle
Air gap appears clogged with debris

Cleaning:

Remove the decorative cap
Remove the inner cover
Clear debris from both the inlet and outlet tubes
Use a bottle brush for thorough cleaning

When the Pump Motor Itself Is the Problem

Sometimes the pump motor runs but has internal issues:

Worn motor bearings:

Motor sounds labored or louder than usual
Pump lacks power to move water against any resistance
More common in dishwashers over 8-10 years old

Failed capacitor:

Motor hums but can’t spin at full speed
Pump sounds weak or struggles

These typically require pump replacement. See our drain pump guide for testing with a multimeter and replacement instructions.

Diagnostic Summary

Use this quick reference:

Symptom	Most Likely Cause
Pump hums, no water moves at all	Check valve stuck closed, blocked hose
Pump hums, water dribbles slowly	Partial hose blockage, debris around impeller
Pump hums, water drains then returns	Check valve stuck open (backflow)
Pump sounds labored	Pump motor wearing out
Water only reaches bucket (not disposal)	Blockage at disposal connection

Cost to Fix These Issues

Problem	DIY Cost	Professional Cost
Blocked drain hose	$0-25 (new hose if needed)	$80-150
Check valve replacement	$15-30	$100-150
Impeller debris removal	$0	$80-120
Pump replacement	$50-100	$200-350

FAQ

Why does my dishwasher sound like it’s draining but the water stays?

The drain pump motor is working, but something is blocking the water path. The most common causes are a stuck check valve, clogged drain hose, or debris wrapped around the pump impeller. Start by checking the drain hose under your sink for kinks, then inspect the check valve.

Can a dishwasher pump run but not pump water?

Yes. The motor can spin while the impeller fails to move water if: the impeller blades are broken, debris is wrapped around the shaft reducing efficiency, or the check valve is stuck closed preventing water from exiting. Listen for any grinding sounds that indicate debris interference.

How do I know if my dishwasher check valve is bad?

Signs of a bad check valve: water drains then returns to the dishwasher, gurgling sounds when the sink drains, or the pump runs but absolutely no water exits. The check valve is usually in the drain hose near the disposal connection. Remove it and check that the flapper swings freely in one direction.

Why is my dishwasher not draining even after I cleaned the filter?

If the filter is clean but drainage still fails, the problem is downstream of the filter — in the pump, check valve, or drain hose. Since you can hear the pump running, focus on the check valve and drain hose. The pump creates pressure, but the water needs a clear path to exit.

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