Dishwasher Not Draining? Here’s What To Check
You open the dishwasher to find a pool of murky water sitting in the bottom. The cycle has finished — or given up halfway through — and your dishes are soaking in the same dirty water they were washed in. You run it again. Same result.
For the cost comparison across every dishwasher fault — and the honest repair-or-bin thresholds — see Dishwasher Repair vs Replace: What Each Really Costs.
Here’s the thing most people get wrong: they assume the drain pump has died and start shopping for a replacement. In reality, the drain system fails in a predictable order, and the two most common culprits — a clogged filter and a jammed impeller — cost nothing to fix and take about ten minutes.
The good news is that you don’t need to guess. Follow the water from the tub to the exterior drain connection: filter, sump, pump, check valve, pressure switch, drain hose. The first component that fails the test is your fault. Most of them are free or cheap to fix.
This page covers that sequence, the checks you can perform yourself, and when a repair makes sense versus when it’s time for a new dishwasher. If you need the complete diagnostic guide with expected readings, the full guide is linked at the bottom.
Quick Diagnosis
Standing water, no sound from the pump: a blocked filter or sump — the most common cause.
Pump hums but no water moves: a jammed impeller.
Pump makes no sound at all, filter clear: the pump motor has failed, or it isn’t receiving power.
Water drains slowly, or only partly: a partial blockage in the filter, hose, or air gap.
Water drains, then returns to the tub: a faulty check valve, or a blockage downstream.
Won’t start a new cycle: the machine can’t drain first — a drain fault, not a control fault.
Water backs up into the sink: a blockage in the air gap or sink drain connection.
Everything tests good but the cycle never drains: a control board fault.
Why Your Dishwasher Won’t Drain
A dishwasher drains in one direction: water leaves the tub through the filter and sump, the pump pushes it through a check valve, and it exits through the drain hose to the air gap, sink drain, or disposal connection.
Every component in that path has one job. When one fails, water stops moving — or moves the wrong way. Because the components are in series, the first one to fail stops everything downstream of it. That’s why the diagnostic order matters: test from the tub outward and stop at the first failure.
The Most Likely Causes
A Clogged Filter Or Sump
The most common cause of standing water, and the easiest to fix. Food debris, grease, and glass shards collect in the filter and sump, blocking the path to the pump.
What to check:
Switch off the power and shut off the water supply.
Remove the bottom rack and the filter assembly — most twist out.
Inspect the filter for food debris, grease, and glass.
Check the sump beneath it for debris.
Clean thoroughly in warm soapy water, reassemble, and run a drain cycle.
This is a ten-minute job with no parts required.
A Jammed Pump Impeller
The drain pump’s impeller gets jammed by debris, glass, or a bone fragment. The motor may hum without moving water, or the pump may run dry.
What to check:
Switch off the power and shut off the water.
Access the pump — usually behind the bottom kick plate or under the sump.
Remove the pump cover and inspect the impeller.
Clear any debris — glass and bone fragments are common.
Check that the impeller turns freely by hand.
Reassemble and test.
Clearing the impeller is free and often restores full drainage immediately.
A Failed Drain Pump Motor
If the impeller isn’t blocked but the pump doesn’t run at all, the motor has failed. This is the fault that genuinely needs a part.
What to check:
Switch off the power and shut off the water.
Disconnect the pump wiring and measure resistance across the motor windings with a multimeter.
An infinite reading means the motor has failed.
Also check for voltage at the pump connector during a drain cycle — no voltage means the fault is upstream (pressure switch or control board).
A replacement pump is $40 to $90 for the part.
A Faulty Check Valve
The check valve stops dirty water flowing back into the tub. When it sticks open or breaks apart, water drains and then returns — or the pump can’t build enough pressure to push water out.
What to check:
Switch off the power and shut off the water.
Locate the check valve — usually at the pump outlet or in the drain hose connection.
Inspect it for debris, a stuck flap, or a broken body.
Test that it allows flow one way and blocks it the other.
Replace if it’s stuck open or broken.
A check valve is $10 to $25.
A Kinked Or Blocked Drain Hose
A crushed, kinked, or internally clogged drain hose prevents water leaving the machine.
What to check:
Pull the dishwasher out and inspect the hose along its full length.
Look for kinks, crushing, or a hose pushed hard against the cabinet.
Disconnect both ends and check for blockages.
On a new installation, check the garbage disposal knockout plug — if it was left in place, the dishwasher can’t drain at all.
Straighten, clear, or replace the hose.
A kinked hose is free to fix. A replacement hose is $10 to $30. A disposal knockout plug is free to remove.
A Faulty Pressure Switch
The pressure switch tells the control board when the tub is empty. If it fails, the dishwasher may think it’s still full, refuse to start a new cycle, or never trigger the drain at all.
What to check:
Switch off the power and shut off the water.
Locate the pressure switch — usually on the sump or the side of the tub, with a small air tube.
Check the air tube for blockages or splits.
Test the switch for continuity with a multimeter.
Replace if it fails the test.
A pressure switch is $20 to $50.
A Blocked Air Gap Or Sink Drain Connection
A clog downstream of the dishwasher — in the air gap or the sink drain — backs water up into the tub.
What to check:
Check the air gap on the sink (if fitted) for debris.
Check the sink drain and the disposal connection for a blockage.
Run the sink tap and check it drains freely.
Clear any blockage.
Clearing a downstream blockage is free.
If You Have A Bosch And See A Code
Bosch dishwashers report drain faults as specific error codes rather than symptoms, and two of them are directly relevant here:
E24 — water not draining, usually a blocked filter or drain hose
E25 — drain pump fault
If your Bosch is showing E15 rather than E24 or E25, that’s a different fault — water sitting in the base tray has tripped the flood switch, not a blocked drain. Bosch Dishwasher E15 Fault Code explains how to find the leak and clear the code.
If your Bosch is showing a code, the code post is the faster route — it decodes the specific fault rather than working through the generic symptom checks.
Bosch Dishwasher E24 Fault Code — what E24 means and how to clear it
Bosch Dishwasher E25 Fault Code — what E25 means and how to clear it
What The Results Tell You
It drains after cleaning the filter: the filter was blocked. Fixed for free.
It drains after clearing the impeller: debris was jamming the pump. Fixed for free.
It drains after clearing the hose or removing the knockout plug: a downstream blockage.
The pump hums but won’t move water: a jammed impeller.
The pump makes no sound and the filter is clear: a failed motor or no power to the pump.
Water drains then returns: a faulty check valve.
It won’t start a new cycle: the pressure switch, or the machine hasn’t drained.
Everything tests good: a control board fault.
Is It Worth Repairing?
Almost always, yes — the drain side is the cheap side.
A clogged filter is free.
A jammed impeller is free.
A kinked hose is free.
A disposal knockout plug is free to remove.
A check valve is $10 to $25.
A drain hose is $10 to $30.
A pressure switch is $20 to $50.
A drain pump is $40 to $90.
Where the maths changes is the pump motor and the control board. A control board is $100 to $200. If your machine is under eight years old and otherwise sound, both are still worth doing. If it’s older, has already had two or more repairs, or the tub or door seals are failing, that money is better put toward a new unit.
Safety Warning
Electrical risk. Dishwashers run on mains voltage. Switch off the power at the circuit breaker before removing any panel or accessing the pump.
Water risk. The machine will hold standing water. Have towels and a shallow tray ready before opening the filter or pump.
Sharp risk. Glass shards and bone fragments are common in the sump and impeller. Wear gloves and use pliers, not fingers.
Plumbing risk. Shut off the water supply before disconnecting any hose or connection.
Slip risk. Water on the floor is a slip hazard. Clean it up immediately.
FAQ
Why is there standing water in the bottom of my dishwasher?
The drain path is blocked somewhere between the sump and the exterior drain. The most common cause is a clogged filter or sump, followed by a jammed pump impeller.
How do I know if my dishwasher drain pump is bad?
If the pump hums but no water moves, the impeller is likely jammed. If it makes no sound at all and the filter is clear, the motor windings have probably failed.
Why is my Frigidaire dishwasher not draining?
The same drain path applies across brands. On a Frigidaire, check the filter and sump first, then the pump impeller. Frigidaire machines commonly collect debris in the sump area.
Why is my Whirlpool dishwasher not draining?
Check the filter, then the check valve — Whirlpool machines commonly show a stuck check valve when water drains and then returns. If the filter and valve are clear, test the pump.
Why is my GE dishwasher not draining?
GE machines often show a pressure switch fault when the drain cycle won’t start. If the filter is clear and the pump runs, test the pressure switch and its air tube.
Why is my Samsung dishwasher not draining?
Check the filter and the drain hose first — a kinked hose or a blocked air gap is common. If both are clear, test the pump impeller and motor.
Can I fix a dishwasher that won’t drain myself?
Yes. A clogged filter or blocked impeller is a ten-minute repair with no parts. A failed pump, check valve, or pressure switch is still DIY-friendly with a multimeter and basic tools.
Is it worth repairing a dishwasher that won’t drain?
Usually yes. Most drain faults are free or under $90 to fix. Only a control board on an older machine makes replacement the better call.
Get The Complete Diagnosis
Need to test each component in the drain path and confirm the fault before buying a part?
The complete guide walks the entire drain path in sequence — filter, sump, pump, check valve, pressure switch, and drain hose — with a step-by-step testing procedure for each, what a good reading looks like versus a failed one, and a repair-or-replace threshold.
The complete guide includes:
Filter cleaning and sump inspection
Pump impeller clearing and motor winding testing
Check valve testing for one-way operation
Drain hose inspection and the disposal knockout plug
Pressure switch testing with expected readings
Air gap and sink drain connection checks
Control board power testing
Repair-or-replace threshold for every component
Dishwasher Not Draining Repair Guide
Complete diagnostic guide for dishwashers that won’t drain.
What’s included:
Full drain path diagnosis in sequence
Filter, sump, pump, and impeller testing
Check valve and drain hose checks
Pressure switch testing
Repair-or-replace guidance
Download instantly
$7.95
Dishes Coming Out Dirty As Well?
If the water drains but the dishes still come out gritty or coated, the fault is in the wash system rather than the drain system.
Dishwasher Not Cleaning Dishes Repair Guide
Complete diagnostic guide for dishwashers that leave dishes dirty.
What’s included:
Wash system diagnosis
Spray arm and filter checks
Detergent and water temperature faults
Pump and valve testing
Repair-or-replace guidance
Download instantly
$7.95
Looking for Brand-Specific Dishwasher Guides?
If your dishwasher is showing an error code, the brand fault-code guides decode it directly.
Repair or Bin?
Before spending money on a repair, find out what is actually wrong with your appliance.
Repair or Bin gives you the information to diagnose the problem and make an informed repair-or-bin decision.
Related Articles
Bosch Dishwasher E24 Fault Code
Decode the E24 drain fault and clear it.
Bosch Dishwasher E25 Fault Code
Decode the E25 drain pump fault.
Bosch Dishwasher Fault Codes
The full Bosch fault code index.
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The Bosch-code shortcut could also mention newer displays such as E:61-02 and E:61-03. In the SGE53B56UC guide, E:61-02 includes an incorrectly fitted pump cover or a blockage, while E:61-03 directs attention to the drain route. This model-specific comparison is useful before buying a pump After any permitted cleaning, refitting the cover correctly matters just as much as clearing the filter. Isolate power, let water cool and watch for broken glass; confirm the full E-Nr before using another model’s instructions.