Dishwasher Won't Drain? Common Causes and Fixes

A dishwasher that won’t drain can leave standing water in the bottom of the appliance, create foul odors, and lead to costly repairs if left unchecked. If you’re wondering, “Why is my dishwasher not draining?” you’re not alone.

In most cases, a clogged filter, a kinked drain hose, or a blocked garbage disposal is to blame. Luckily, you can fix many of these issues on your own. This guide will walk you through the most common reasons your dishwasher isn’t draining, how to troubleshoot the problem, and when to call a professional.

Common Reasons Your Dishwasher Won't Drain

If you open your dishwasher and see standing water, one of these culprits is likely the cause:

1. Clogged Dishwasher Drain or Filter

Over time, food debris, grease, and soap scum can build up in the dishwasher filter and drain, blocking water flow. If this happens, you might notice water pooling at the bottom, dishes not fully cleaned, and an unpleasant odor.

How to fix it:

[Embed existing “How to Clean Your Dishwasher” video]: 

How to Clean Your Dishwasher | Roto-Rooter

Take the following steps to clean your dishwasher:

• Remove the bottom rack and locate the filter (usually at the base of the tub).
• Twist or pull it out (check your user manual for instructions).
• Rinse it under warm water and scrub it with a soft brush if needed.
• Check the drain beneath the filter for debris and clear it out.

2. Blocked or Kinked Drain Hose

The drain hose carries wastewater from the dishwasher to the sink or garbage disposal. When it gets blocked or kinked, water cannot drain correctly, leading to standing water, gurgling sounds during the drain cycle, and dishes that just won't get clean.

How to fix it:

Fixing a dishwasher drain hose requires you to check the hose for issues:

• Turn off the power to the dishwasher for safety.
• Locate the drain hose (usually behind the dishwasher or under the sink).
• Check for kinks and straighten the hose if needed.
• If clogged, detach the hose and flush it with warm water, or use a plumber’s snake to clear any blockages.

3. Clogged Garbage Disposal or Air Gap

Many dishwashers drain through the garbage disposal. If food waste builds up in the garbage disposal, it can block the drain and lead to dishwasher clogs and water buildup.

Other dishwashers have an air gap, which is a small fixture near the sink that ensures wastewater flows into the kitchen sink drain. If this gets clogged with food waste, you might find water gushing out of the air gap or not be able to run a cycle at all.

How to fix it:

The primary way to fix this problem is to clear away debris and blockages:

• Run the garbage disposal for 30 seconds to clear any blockages.
• Check the air gap — twist off the cap and remove debris inside.
• If water still won’t drain, disconnect the hose from the disposal and clear any gunk inside.

4. Faulty Drain Pump or Check Valve

The drain pump forces water out of the dishwasher, while the check valve prevents dirty water from flowing back in. If either component fails, water won’t drain properly. Typically, the drain pump is the issue if the dishwasher is not draining completely. You might also hear loud grinding noises.

The check valve might be the issue if water initially drains but flows back into the dishwasher. This can also lead to gurgling noises as the water flows the wrong way.

How to fix it:

If you've checked the other components of your dishwasher and it's still not working, chances are one of these two components is the issue:

• Unplug the dishwasher and check the drain pump for debris.
• If the pump is damaged or the check valve is stuck, you may need professional dishwasher repair.

How to Fix a Dishwasher That Won't Drain

If your dishwasher won't drain, don't panic. By following the basic steps of how to repair a clogged dishwasher, you can solve most problems without calling in the professionals:

• Step 1: Run a Cleaning Cycle with Vinegar and Baking Soda: Pour one cup of vinegar into the bottom of the dishwasher and run a short cycle. Sprinkle baking soda in the bottom and let it sit overnight, then run another cycle the next morning. As a bonus, this can also take care of nasty dishwasher smells.

• Step 2: Check the Dishwasher Filter and Clean It: Remove the filter and rinse it under warm water. Scrub off grease and food particles with a soft brush.

• Step 3: Inspect and Clear the Drain Hose: Locate the drain hose under the sink or behind the dishwasher. Check for kinks and flush out any debris.

• Step 4: Run the Garbage Disposal: If your dishwasher drains through the garbage disposal, running it for 30 seconds may clear a clog.

• Step 5: Reset the Dishwasher: Turn off the dishwasher and unplug it for 5-10 minutes. Restart and run a short cycle to test if the drain issue is resolved.

When to Call a Plumber for a Dishwasher Repair

If none of the above tricks work, your best bet is to call in a professional. Plumbers can fix dishwashers in all states of disrepair, whether they're not draining or making sounds during a wash cycle. In particular, you'll want to call a plumber if:

• Water continues pooling at the bottom despite troubleshooting.
• The drain pump or motor is malfunctioning.
• The drain hose is cracked or severely clogged.

FAQs about Dishwashers that Won’t Drain

Why Is My Dishwasher Not Draining and Leaking?

A clogged drain or filter can cause water to back up and leak from the door. If water leaks onto your floor, you might also have a damaged door seal or an overfilled dishwasher. Your detergent could also be to blame if the cleaner creates too many suds in the dishwasher. 

Can a Clogged Filter Cause My Dishwasher to Stop Draining?

Yes. A dirty filter is one of the most common reasons dishwashers don’t drain properly.

How Much Does It Cost to Repair a Clogged Dishwasher?

Basic fixes like cleaning the filter are free if you don't count elbow grease. Calling in a plumber will cost more, depending on the complexity of the repair and the cost of parts.

Do Plumbers Fix Dishwashers?

Plumbers can fix drain-related issues, replace hoses, and repair pumps. For electrical problems, you might need an appliance repair technician.

How to Keep Your Dishwasher in Top Shape

It's not uncommon to experience a dishwasher that won't drain. Luckily, you can prevent these issues from happening with regular maintenance, including:

• Clean the filter every few weeks to prevent clogs.
• Run hot water and vinegar through the dishwasher monthly to clear buildup.
• Scrape off food debris before loading dishes.
• Check the drain hose periodically for blockages or kinks.

If your dishwasher still doesn’t drain after troubleshooting, it may be time to call a professional. Roto-Rooter is here to help. 

Roto-Rooter’s 24/7 plumbers and drain technicians can unclog your dishwasher, so backups are a thing of the past. Schedule your service now or call 800-768-6911 to set up an appointment.