Dishwasher Drain Pump: Testing, Troubleshooting + Replacement Guide
Quick Answer: The drain pump is responsible for pushing water out of your dishwasher. If it fails, water stays in the tub. Test by listening during the drain cycle — humming with no drainage suggests a stuck impeller, while silence indicates motor failure.
The drain pump is one of the few mechanical parts in your dishwasher. When it works, you don’t notice it. When it fails, your dishwasher becomes a water-filled box.
This guide covers how the pump works, how to test it, and when to repair vs. replace. For replacement parts, check sites like RepairClinic or PartSelect that carry OEM drain pumps for all major brands.
Video Guide
Video: “Dishwasher Not Draining — Dishwasher Troubleshooting” by RepairClinic.com
How the Drain Pump Works
The drain pump has two main components:
- Electric motor — Powers the pump, typically runs on 120V
- Impeller — Spinning blades that push water through the drain hose
During the drain portion of a cycle, the control board sends power to the pump motor. The motor spins the impeller, which creates suction to pull water from the tub and push it through the drain hose.
Pump types:
| Type | Characteristics |
|---|---|
| Direct drive | Motor directly spins impeller, most common |
| Belt drive | Motor drives impeller via belt (older machines) |
| Reversible | Wash and drain functions in one motor (some brands) |
Signs Your Drain Pump Is Failing
Complete Silence During Drain Cycle
If you hear nothing when the dishwasher should be draining, the pump motor may have:
- Burned out completely
- Failed electrically (no power reaching it)
- Seized internally
Humming But No Drainage
The motor runs but water doesn’t leave. This usually means:
- Impeller is jammed with debris
- Impeller blades are broken
- Motor runs but shaft is seized
Grinding or Rattling Sounds
Something is interfering with the impeller:
- Glass shards
- Broken dish pieces
- Bones or fruit pits
- Paper labels from jars
Intermittent Operation
The pump works sometimes but not consistently:
- Motor is overheating and cutting out
- Electrical connection is loose
- Motor bearings are failing
How to Test a Dishwasher Drain Pump
Test 1: Listen Test
The simplest diagnostic — no tools required.
- Start a wash cycle and let it fill
- Wait for the drain portion (or cancel the cycle)
- Put your ear near the bottom front of the dishwasher
- Listen for motor sound
Results:
- Steady hum = Motor works, check for obstructions
- Silence = Motor failure or no power
- Grinding = Debris in pump
- Brief hum then stop = Motor overheating or seized
Test 2: Visual Inspection
Check the impeller for damage or obstructions.
To access the pump area:
- Remove the lower dish rack
- Remove the filters
- Look into the sump area
- Some models have a removable cover over the impeller
- Use a flashlight to see the impeller blades
What to look for:
- Debris wrapped around the impeller shaft
- Cracked or missing impeller blades
- Visible obstructions (glass, plastic, etc.)
Can you spin it by hand? Reach in carefully and try to rotate the impeller. It should spin freely. If it’s stuck, something is jamming it.
Test 3: Multimeter Test
This confirms whether the motor itself is functional.
You’ll need:
- Multimeter (set to ohms/resistance)
- Access to the pump motor terminals
Testing procedure:
- Disconnect power to the dishwasher (breaker or unplug)
- Access the pump (usually from bottom of dishwasher)
- Disconnect the wire harness from the pump motor
- Set multimeter to measure resistance (ohms)
- Touch probes to the motor terminals
- Read the resistance value
Interpreting results:
| Reading | Meaning |
|---|---|
| 5-15 ohms | Motor winding is good |
| 0 ohms (short) | Motor has internal short — replace |
| Infinite/OL | Open circuit — motor is dead, replace |
| Within range but pump doesn’t work | May be mechanical failure |
Ground test: Touch one probe to a motor terminal and one to the metal pump housing. You should read infinite resistance (no continuity). Any reading indicates a ground fault — replace the pump.
Accessing the Drain Pump
The pump is at the bottom of the dishwasher. Access depends on your model:
Method 1: Through the Kickplate (Most Common)
- Turn off power at the breaker
- Remove the kickplate (lower front panel)
- The pump is visible — usually a cylindrical motor with hoses
- You may need to remove screws or clips holding the pump
Method 2: From Underneath
Some models require laying the dishwasher on its side or back:
- Turn off power and water supply
- Disconnect the drain hose and supply line
- Pull the dishwasher out from the cabinet
- Carefully tip onto side or back
- Access pump from the bottom of the unit
Method 3: From Inside the Tub
A few models allow pump access by removing internal covers:
- Remove filters and spray arms
- Look for a cover plate in the sump area
- Remove screws to access pump/impeller
Consult your manual for the correct access method for your model.
Replacing a Dishwasher Drain Pump
If testing confirms the pump has failed, replacement is straightforward for most models.
You’ll need:
- Replacement pump (match your model number)
- Screwdrivers (Phillips and flat-head)
- Pliers
- Towels for water
- Bucket
Replacement Steps (General)
- Disconnect power at the breaker
- Turn off water supply to the dishwasher
- Remove the kickplate for access
- Photograph connections before disconnecting anything
- Disconnect wire harness from the pump motor
- Disconnect drain hoses (have towels ready for water)
- Remove mounting screws or clips holding the pump
- Twist/pull pump to remove (some have quarter-turn locks)
- Install new pump in reverse order
- Reconnect hoses and wire harness
- Check for leaks before replacing the kickplate
- Run a test cycle to verify operation
Finding the Right Replacement Pump
Use your dishwasher’s model number to find the exact part:
- PartSelect.com — Enter model number to find compatible parts
- RepairClinic.com — Model lookup with diagrams
- Amazon — Search by pump model number
- Manufacturer parts direct — Whirlpool, GE, Bosch, etc.
Typical pump cost: $50-100 for most brands
Repair vs. Replace: The Decision
| Factor | Lean Toward Repair | Lean Toward Replace |
|---|---|---|
| Dishwasher age | Under 7 years | Over 10 years |
| Repair cost | Under $150 total | Over $250 |
| Previous repairs | First major issue | Multiple recent repairs |
| Dishwasher quality | Mid-high range | Entry level |
Rule of thumb: If repair cost exceeds 50% of a new dishwasher price, and the unit is over 8 years old, replacement often makes more sense.
New dishwasher costs:
- Entry level: $400-600
- Mid-range: $600-900
- Premium: $900-1,500+
Professional Pump Replacement Cost
If DIY isn’t your thing, here’s what to expect:
| Component | Typical Cost |
|---|---|
| Pump part | $50-100 |
| Labor (1-2 hours) | $100-200 |
| Total | $150-350 |
Getting multiple quotes is worthwhile — prices vary significantly between service companies.
Preventing Pump Failure
While pumps eventually wear out, you can extend their life:
- Clean filters regularly — Debris that passes through clogs the pump
- Scrape dishes — Don’t let large food particles enter
- Remove labels from jars — Paper labels clog pumps
- Check for broken glass — Remove dishes carefully, watch for chips
- Run hot water first — Helps soften any debris
FAQ
How do I know if my dishwasher drain pump is bad?
Listen during the drain cycle. Complete silence means the motor has failed or isn’t getting power. Humming without drainage indicates a jammed impeller or mechanical failure. Confirm with a multimeter test — a good pump motor reads 5-15 ohms resistance.
How much does it cost to replace a dishwasher drain pump?
The pump part costs $50-100 for most brands. If hiring a professional, expect $150-350 total including parts and labor. DIY replacement saves $100-200 in labor costs if you’re comfortable with basic appliance repair.
Can I run my dishwasher with a broken drain pump?
No. Without drainage, water accumulates and eventually overflows or causes damage. The dishwasher will likely not complete cycles properly. Fix the pump before using the dishwasher again.
How long do dishwasher drain pumps last?
Most drain pumps last 8-12 years under normal use. Factors that shorten pump life include debris damage (glass, bones), running without proper filters, and hard water buildup. Regular filter cleaning extends pump life.
Why does my dishwasher pump keep running?
If the pump runs continuously without stopping, the control board may be malfunctioning or a float switch is stuck. This is different from pump failure and usually requires professional diagnosis. Turn off the dishwasher at the breaker to prevent damage.
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