Quick answer
If your dishwasher isn't draining, first check the filter and drain hose for clogs. Clear any blockages and ensure the drain hose is properly looped above the sink. If the issue persists, inspect the pump and garbage disposal knockout plug.
Confirm the symptom
- Water remains in the dishwasher after a cycle ends
- Dishes are still wet or have standing water
- Drain hose is clogged or kinked
Tools and prep
- Screwdriver
- Plunger or plumber's snake
- Bucket or towels
- Flashlight
- Work gloves
- Turn off power at circuit breaker
- Shut off water supply to dishwasher
Step-by-step troubleshooting
- Check the Filter
Do: Remove and clean the filter under the bottom rack.Observe: Filter is clogged with food debris.Means: Clogged filter prevents proper drainage.Next: Clean the filter thoroughly and reinstall.
- Inspect the Drain Hose
Do: Locate and check the drain hose for clogs or kinks.Observe: Hose is clogged or improperly looped.Means: Blockage or incorrect installation hinders drainage.Next: Clear the clog or adjust the hose to form a high loop.
- Check the Garbage Disposal Knockout
Do: If connected to a disposal, verify the knockout plug is removed.Observe: Knockout plug is still in place.Means: Water cannot drain through the disposal.Next: Remove the knockout plug with a screwdriver.
- Clean the Sump Area
Do: Use a flashlight to inspect the sump for debris.Observe: Debris or food particles are present.Means: Clogged sump prevents water from draining.Next: Remove debris with a sponge or small brush.
- Test the Pump
Do: Run a cycle and listen for the pump to engage.Observe: Pump is silent or makes unusual noises.Means: Pump may be faulty or clogged.Next: Check for clogs in the pump area or consider replacing the pump.
- Check the Air Gap
Do: Inspect the air gap on the sink for blockages.Observe: Air gap is clogged or not properly connected.Means: Blocked air gap restricts drainage.Next: Clean the air gap and ensure it is securely connected.
- Examine the Sink Trap
Do: Check the sink trap for clogs if the dishwasher drains into it.Observe: Debris or buildup is present in the trap.Means: Clogged sink trap prevents proper drainage.Next: Clear the trap using a plumber's snake or plunger.
- Verify High Loop Installation
Do: Ensure the drain hose has a high loop above the sink.Observe: Hose is installed without a high loop.Means: Improper installation allows water to siphon back.Next: Adjust the hose to form a high loop and resecure it.
Common causes
| Cause | Likelihood | Difficulty | Part often needed |
|---|---|---|---|
| Clogged Filter Food particles and debris block the filter, preventing water from draining. | Common | Easy | Filter cleaning kit |
| Clogged Drain Hose Grease, food, or debris can clog the hose, stopping water flow. | Common | Easy–Medium | Plumber's snake |
| Blocked Sump Food particles and debris accumulate in the sump, blocking drainage. | Sometimes | Easy | Sump cleaning brush |
| Faulty Pump A worn or damaged pump cannot push water out of the dishwasher. | Sometimes | Medium | Pump motor assembly |
| Clogged Air Gap The air gap prevents backflow but can become clogged with debris. | Sometimes | Easy | Air gap cleaning tool |
| Clogged Sink Trap If the dishwasher drains into the sink trap, it can become clogged. | Sometimes | Medium | Plumber's snake |
| Improper Drain Hose Installation A missing high loop or kinked hose can prevent proper drainage. | Common | Easy | Drain hose |
| Garbage Disposal Knockout Not Removed The knockout plug must be removed to allow water to drain into the disposal. | Rare | Easy | Knockout plug removal tool |
| Faulty Float Switch A faulty float switch may prevent the pump from activating. | Rare | Medium | Float switch assembly |
| Blocked Drain Pump Impeller The impeller can become blocked by large food particles, stopping the pump. | Sometimes | Medium | Drain pump impeller |
Parts matching
Replace or clean the following parts if they are damaged or clogged:
- Filter
- Drain hose
- Pump motor assembly
- Air gap
- Sink trap
- Garbage disposal knockout plug
- Sump cleaning brush
Always turn off the power and water supply before replacing or cleaning parts.
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When to call a professional
- Standing water persists after multiple attempts to clear clogs
- Pump makes loud or unusual noises and does not drain
- Drain hose or pump is damaged and needs replacement
- You are unsure about electrical components or complex repairs
- The dishwasher is under warranty and professional service is required
FAQ
How often should I clean my dishwasher filter?
Clean the filter every 1–2 months to prevent clogs and ensure proper drainage.
Can a clogged air gap cause drainage issues?
Yes, a clogged air gap can block water flow and prevent the dishwasher from draining properly.
Why is my dishwasher making noise but not draining?
A noisy pump may indicate a clog or a faulty pump motor that needs inspection or replacement.
What is a high loop on a drain hose?
A high loop is a bend in the drain hose above the sink that prevents water from siphoning back into the dishwasher.
How do I know if my garbage disposal knockout plug is installed correctly?
The knockout plug should be removed to allow water to flow into the disposal. If it's still in place, the dishwasher will not drain.
Can a faulty float switch cause drainage problems?
Yes, a faulty float switch may prevent the pump from activating, leading to drainage issues.