Dishwasher Won't Drain – Causes, Fixes & Replacement Parts

Is your dishwasher leaving standing water at the bottom after a cycle? A dishwasher that won't drain is one of the most common appliance problems, but the good news is it's usually fixable with a simple part replacement or cleaning. This guide will help you diagnose the issue, understand what's causing it, and find the right replacement parts to get your dishwasher draining properly again.

✓ Common Symptoms of a Dishwasher That Won't Drain

• Standing water pooling at the bottom of the dishwasher after the cycle
• Dishwasher stops mid-cycle with water inside
• Loud grinding, humming, or buzzing noise during the drain cycle
• Slow drainage or partial draining
• Water backing up into the dishwasher from the sink
• Error codes related to drainage (varies by brand and model)
• Dishes remain wet or dirty due to incomplete cycle
• Foul odors from stagnant water

✓ What Causes a Dishwasher Not to Drain?

1. Clogged or Failed Drain Pump

The drain pump is responsible for pushing water out of the dishwasher. Over time, food particles, broken glass, or debris can clog the pump or damage the impeller. If you hear a humming or grinding noise but no water is draining, the pump is likely the culprit.

Solution: Inspect and clean the pump filter. If the pump motor is burned out or the impeller is damaged, you'll need to replace the drain pump assembly.

Shop Drain Pumps: WPW10348269 Whirlpool Drain Pump

2. Blocked Drain Hose

The drain hose carries water from the dishwasher to your home's plumbing. Kinks, clogs, or improper installation can prevent water from flowing out.

Solution: Disconnect the drain hose and check for blockages. Straighten any kinks and ensure the hose is installed with a high loop or air gap to prevent backflow.

3. Clogged Air Gap or Garbage Disposal

If your dishwasher drains through an air gap or garbage disposal, blockages in these areas can prevent proper drainage.

Solution: Clean the air gap by removing the cap and clearing any debris. If connected to a garbage disposal, run the disposal to clear any clogs and ensure the knockout plug was removed during installation.

4. Faulty Drain Valve or Check Valve

Some dishwashers use a drain valve or check valve to control water flow. If this valve is stuck closed or damaged, water won't drain.

Solution: Inspect the valve for debris or damage. Replace if necessary.

5. Clogged Filter or Sump

The dishwasher filter traps food particles and debris. If it becomes clogged, water can't reach the drain pump.

Solution: Remove and clean the filter regularly (at least once a month). Check the sump area for debris.

6. Faulty Control Board or Timer

In rare cases, a malfunctioning control board or timer may fail to signal the drain pump to operate.

Solution: Test the drain pump for continuity. If the pump is functional but not receiving power, the control board may need replacement.

✓ DIY Troubleshooting Steps

1. Check the filter: Remove the lower dish rack and spray arm. Locate the filter at the bottom of the tub and clean it thoroughly.
2. Inspect the drain pump: Look for visible debris or damage. Listen for unusual noises during the drain cycle.
3. Examine the drain hose: Disconnect and check for kinks or clogs. Ensure proper installation with a high loop.
4. Clean the air gap: Remove the cap and clear any blockages.
5. Run the garbage disposal: If connected, run the disposal to clear any clogs.
6. Test the drain pump: Use a multimeter to check for continuity. Replace if faulty.

✓ Most Common Replacement Parts for Drainage Issues

• Drain Pump Assembly: The most common part to fail. Fixes grinding noises and complete drainage failure.
• Drain Hose: Replace if cracked, kinked, or clogged beyond cleaning.
• Check Valve: Prevents backflow and ensures proper drainage direction.
• Drain Valve Solenoid: Controls the opening and closing of the drain valve.
• Filter Assembly: Replace if damaged or warped.

✓ Shop Dishwasher Drain Parts by Brand

Whirlpool: WPW10348269 Drain Pump

KitchenAid: Compatible with Whirlpool parts

Maytag: Compatible with Whirlpool parts

GE: Coming soon

Bosch: Coming soon

Samsung: Coming soon

LG: Coming soon

✓ When to Call a Professional

While many drainage issues can be fixed with DIY repairs, you should call a professional if:

• You're uncomfortable working with electrical components
• The problem persists after replacing the drain pump and clearing blockages
• You suspect a control board or wiring issue
• There's a leak or water damage around the dishwasher

✓ Prevention Tips

• Scrape food debris off dishes before loading (no need to pre-rinse completely)
• Clean the filter monthly to prevent clogs
• Run hot water in the sink before starting the dishwasher to ensure proper temperature
• Use the correct amount of detergent (too much can cause buildup)
• Run the garbage disposal before starting the dishwasher if they share a drain
• Inspect and clean the spray arms regularly

✓ Why Choose XPart Supply for Dishwasher Parts?

• 30+ years of appliance parts expertise in Canada
• Genuine OEM and premium aftermarket options available
• Fast shipping across Canada with tracking
• Expert phone support to help you find the right part
• Guaranteed fit or your money back
• Canadian-owned and operated business

✓ Frequently Asked Questions

Q: Why is there standing water in my dishwasher after the cycle?
A: Standing water is usually caused by a clogged drain pump, blocked drain hose, or dirty filter. Start by cleaning the filter and checking for visible blockages. If the problem persists, the drain pump may need replacement.

Q: How do I know if my dishwasher drain pump is bad?
A: Signs of a bad drain pump include loud grinding or humming noises, complete drainage failure, or the dishwasher stopping mid-cycle. You can test the pump with a multimeter to check for continuity.

Q: Can I use my dishwasher if it won't drain?
A: It's not recommended. Running a dishwasher that won't drain can cause water damage, mold growth, and further damage to internal components. Fix the drainage issue before using it again.

Q: How much does it cost to replace a dishwasher drain pump?
A: Drain pumps typically range from $30-$100 depending on the brand and whether you choose OEM or aftermarket. DIY installation can save you $100-$200 in labor costs.

Q: How long does a dishwasher drain pump last?
A: Most drain pumps last 5-10 years with proper maintenance. Regular filter cleaning and avoiding large food debris can extend the pump's lifespan.

Q: Will a clogged garbage disposal prevent my dishwasher from draining?
A: Yes, if your dishwasher drains through the garbage disposal, a clog can cause backflow and prevent proper drainage. Always run the disposal before starting the dishwasher.

Need help finding the right part? Contact our parts experts at XPart Supply. We'll help you identify the exact part you need based on your dishwasher's make and model.