Dishwasher Not Draining? Here is How to Fix a Dishwasher that Won’t Drain

7 Safe DIY Troubleshooting Steps before Calling a Dishwasher Technician

When a dishwasher is not draining, the most common causes are a clogged filter, food or glass in the sump area, a blocked drain hose, a clogged air gap, a backed-up garbage disposal, or a failing drain pump.

According to Alex, an Appliance EMT master repair technician with over 10 years of experience repairing dishwashers in the Metro Atlanta area, homeowners should start with the safest and simplest checks before assuming the dishwasher needs a new pump.

Sometimes the dishwasher will not drain at all. Other times, it drains slowly, leaves standing water in the bottom, or backs dirty water up into the sink or garbage disposal. The good news is that many dishwasher drainage problems can be checked safely before calling a repair technician.

Alex says one of the biggest mistakes homeowners make is jumping straight to part replacement.

“A lot of dishwasher drain problems start outside the pump,” Alex explains. “Before replacing parts, it is always smart to check the filter, drain hose, disposal connection, and sump area first.”

Here are seven safe DIY troubleshooting steps homeowners can try when a dishwasher won’t drain.

Quick Dishwasher Troubleshooting Summary

Problem	Possible Cause	Solution
Standing Water	Interrupted Cycle	Press Cancel/Reset
Slow Draining	Clogged Filter	Rinse under warm water
Humming Sound	Blocked Pump/Impeller	Check sump for glass/debris
Water Backing Up	Garbage Disposal	Run disposal; check knockout plug

7 Safe Things to Try First

Before replacing parts or calling for service, homeowners can safely try these dishwasher drain troubleshooting steps:

1. Reset the dishwasher and run a drain cycle.
2. Clean the dishwasher filter.
3. Check the sump area for food, glass, or debris.
4. Run the garbage disposal and inspect the dishwasher drain connection.
5. Clean the air gap if the sink has one.
6. Check the drain hose for kinks, clogs, or poor routing.
7. Run a hot cleaning cycle if the dishwasher drains slowly.

These steps can help answer common questions like “Why is my dishwasher not draining?”, “Why is there standing water in the bottom of my dishwasher?”, and “How do I fix a dishwasher that won’t drain?”

First, Take Basic Safety Steps

Before trying to fix a dishwasher that is not draining, safety comes first.

The dishwasher should be turned off before reaching inside. If the homeowner needs to inspect the filter, sump area, or drain connection more closely, Alex recommends turning off power to the dishwasher at the breaker or unplugging it if the plug is accessible.

It is also smart to wear gloves. Standing dishwasher water can hide broken glass, bones, food scraps, toothpicks, plastic pieces, and sharp debris.

A few helpful items include:

• Towels
• A small cup or bowl
• A shallow pan
• Gloves
• A flashlight
• A soft brush
• Needle-nose pliers

Alex’s field tip: never reach blindly into the bottom of a dishwasher. If a glass broke during a cycle, the pieces can settle near the filter or drain opening.

1. Make Sure the Dishwasher Cycle Actually Finished

A dishwasher may appear to have a drainage problem if the cycle was interrupted before the final drain.

Alex says he has seen plenty of dishwashers with standing water simply because the door was opened mid-cycle, the unit lost power, or someone accidentally paused the cycle.

The homeowner should close the dishwasher door firmly and press Cancel, Drain, Reset, or Start/Reset, depending on the model. Many dishwashers will run a short drain cycle after being reset.

During this step, listen carefully.

If the dishwasher tries to drain, you may hear a low hum followed by water moving through the drain hose. If the dishwasher hums but does not drain, there may be a clog, a blocked pump area, or a failing drain pump. If you are unsure whether the sound is normal can also review Appliance EMT’s guide to decoding dishwasher sounds and what is normal or not.

If there is no sound at all, the issue may involve the door latch, control board, wiring, or power supply.

2. Clean the Dishwasher Filter

A clogged dishwasher filter is one of the most common reasons a dishwasher won’t drain.

Most modern dishwashers have a removable filter at the bottom of the tub, usually under the lower spray arm. Over time, this filter can collect grease, food particles, seeds, paper labels, broken-down detergent residue, and small bits of debris.

When the filter is blocked, water cannot move through the dishwasher properly.

To clean the dishwasher filter:

• Remove the lower dish rack.
• Locate the filter at the bottom of the dishwasher.
• Twist and lift the filter out if it is removable.
• Rinse it under warm water.
• Use a soft brush to remove stuck-on food or grease.
• Reinstall the filter securely.

Alex says this is one of the first things he checks on service calls for a dishwasher not draining.

3. Check the Bottom of the Dishwasher for Food, Glass, or Debris

After removing the filter, the homeowner should inspect the drain sump area. This is the lower area where water collects before the dishwasher pumps it out.

If the dishwasher has standing water in the bottom, the sump area may be blocked by debris.

Alex says he commonly finds:

• Broken glass
• Bones
• Popcorn kernels
• Fruit pits
• Toothpicks
• Plastic pieces
• Jar labels
• Twist ties
• Small utensils
• Pieces of food packaging

These items can block water from leaving the dishwasher or jam the drain pump impeller.

The homeowner can use a flashlight to look into the sump area and carefully remove visible debris. Gloves should be worn, and needle-nose pliers are safer than fingers if broken glass may be present.

Real Dishwasher Repair Example from Alex that could have been a DIY Fix

In one call, for a dishwasher repair in Alpharetta, Alex said that he was called in because a homeowner thought the drain pump to his dishwasher had broken down. The dishwasher had standing water in the bottom, and during the drain cycle it made a low humming sound but would not push water out.

After turning off power and checking the filter, Alex found a small piece of broken glass and food debris lodged near the sump area. The pump was trying to run, but the debris was blocking water from moving through the drain path.

Once the debris was removed, the filter was cleaned, and the dishwasher was tested through a drain cycle, the unit drained normally again.

Alex says this kind of problem is common.

“A dishwasher can sound like it has a bad pump when something is actually stuck near the drain area,” Alex explains. “That is why checking the filter and sump area first can save a homeowner from replacing a part they may not need.”

4. Check the Garbage Disposal Connection

If the dishwasher is not draining into the garbage disposal, the issue may be under the sink instead of inside the dishwasher.

Many dishwashers drain through a hose connected to the garbage disposal. If the disposal is clogged, backed up, or recently replaced, it can stop the dishwasher from draining.

One common problem is the garbage disposal knockout plug. New garbage disposals usually have a small plug inside the dishwasher drain inlet. If that plug is not removed during installation, the dishwasher cannot drain into the disposal.

This is especially likely if the dishwasher stopped draining right after a new garbage disposal was installed.

The homeowner can also run the garbage disposal with cold water for 20 to 30 seconds. If the disposal is full of food waste, it may slow down or block the dishwasher drain.

5. Clean the Air Gap If the Kitchen Sink Has One

Some homes have a dishwasher air gap mounted on the sink or countertop. It usually looks like a small chrome or plastic cylinder near the faucet.

The air gap helps prevent dirty sink water from flowing back into the dishwasher. If it becomes clogged, the dishwasher may not drain properly. In some cases, water may spill out of the air gap and onto the sink during the drain cycle.

To clean the dishwasher air gap:

• Remove the outer air gap cover.
• Lift off or unscrew the inner cap if possible.
• Check for food debris or buildup.
• Clean the opening with a small brush, paper towel, or pipe cleaner.
• Run a short drain cycle and watch for water movement.

Alex says air gap clogs are small problems that can cause big drainage symptoms.

6. Inspect the Dishwasher Drain Hose for Kinks, Clogs, or Poor Routing

The dishwasher drain hose carries dirty water from the dishwasher to the sink drain, garbage disposal, or air gap. If this hose is kinked, pinched, clogged, or installed incorrectly, the dishwasher may leave water in the bottom after a cycle.

The homeowner can usually see part of the drain hose under the sink. It is often a flexible corrugated hose connected to the garbage disposal or sink plumbing.

Look for:

• Sharp bends in the hose
• Pinched sections
• Loose hose clamps
• Grease buildup near the connection
• A hose shoved too far into the cabinet
• A missing high loop

A high loop means the dishwasher drain hose rises up under the countertop before connecting to the drain. This helps keep dirty sink water from flowing back into the dishwasher.

7. Run a Hot Cleaning Cycle for Grease and Buildup

If the dishwasher drains slowly but still moves some water, grease and buildup may be part of the problem.

Alex says this happens often when a dishwasher is used on short cycles, low-temperature cycles, or with too much detergent. Grease and soap residue can build up in the filter, sump area, drain hose, and internal passages.

One thing that helps is running an empty hot cycle with a dishwasher-safe cleaner.

To do this:

• Remove food debris from the filter and sump area first.
• Reinstall the clean filter.
• Add a dishwasher cleaner according to the product instructions.
• Run the hottest normal cycle.
• Check whether the dishwasher drains better afterward.

White vinegar may help with light odor or mineral buildup, but Alex usually recommends a cleaner designed for dishwashers when grease is involved.

How to Drain a Dishwasher Manually

If there is a lot of standing water in the dishwasher, the homeowner may need to remove some of it before cleaning the filter or checking the sump area.

To manually drain a dishwasher:

1. Turn off the dishwasher.
2. Place towels around the front of the unit.
3. Remove the lower rack.
4. Use a cup, bowl, or small container to scoop water into a bucket.
5. Use towels or a sponge to soak up the remaining water.
6. Once the water level is low, remove and clean the filter.

What Not to Do When a Dishwasher Won’t Drain

Over the years, Alex has received many calls from homeowners who started a simple repair DIY for their dishwasher and ended up calling for a technician after something went wrong. So here are his tips to make the DIY dishwasher repair as smooth as possible.

Alex warns homeowners not to use chemical drain cleaner in a dishwasher.

Drain cleaners are made for plumbing pipes, not dishwasher pumps, seals, hoses, and internal components. They can damage parts and leave chemical residue inside an appliance used to clean dishes.

Don’t Use Brute Force on your dishwasher

You should also avoid forcing covers, filters, or spray arms loose with a screwdriver. Dishwasher parts vary by brand and forcing them can break tabs or seals which would then require a certified dishwasher repair technician to either fix or replace the part for you,

Avoiding repeated cycles on your dishwasher

When the dishwasher is already full of dirty standing water. If the drain path is clogged, running more cycles can cause leaking, push debris deeper, or worsen the problem.

Why Is My Dishwasher Not Draining?

A dishwasher may not drain for several reasons. The most common causes include a clogged filter, blocked sump area, kinked drain hose, clogged air gap, backed-up garbage disposal, missing high loop, failed drain pump, or plumbing blockage.

Alex says the best way to troubleshoot is to start with the easiest and safest checks first. Many dishwasher drainage problems can be found without removing the dishwasher from the cabinet.

Why Is There Standing Water in the Bottom of My Dishwasher?

Standing water in the bottom of the dishwasher usually means the water did not leave during the drain portion of the cycle.

A small amount of water near the filter may be normal on some models, but a large pool of dirty water is not. If water remains after every cycle, the dishwasher should be checked for a clogged filter, blocked drain hose, drain pump issue, or backup from the sink drain.

What If the Dishwasher Is Not Draining but There Is No Clog?

If the filter, drain hose, air gap, and disposal connection all look clear, the problem may be mechanical or electrical.

Possible causes include:

• Failed drain pump
• Jammed pump impeller
• Faulty check valve
• Bad drain solenoid on some models
• Wiring issue
• Control board problem
• Door latch issue
• Drain sensor or float-related problem

Alex says this is when proper diagnosis matters. A dishwasher can fail to drain even when there is no visible clog.

When to Call a Dishwasher Repair Technician

If the dishwasher still won’t drain after doing these safe DIY steps, it’s probably time to call a professional appliance repair technician from Appliance EMT.

Alex recommends scheduling services if:

• The dishwasher hums but does not drain.
• The dishwasher is silent during the drain cycle.
• The drain pump makes grinding or buzzing sounds.
• Water returns to the dishwasher after draining.
• The breaker trips during the cycle.
• The dishwasher shows an error code.
• There is leaking under the dishwasher.
• The drain hose and filter are clear, but water still remains.
• The dishwasher has standing water after every cycle.

At that point, the issue may involve the drain pump, check valve, control board, wiring, internal hose, or a blockage deeper in the system.

Alex says a good technician should test before replacing parts. The goal is to confirm whether the dishwasher is trying to drain, whether the pump is receiving power, whether the impeller is blocked, and whether the drain path is open.

Quick Recap: 7 Safe Things to Try When a Dishwasher Is Not Draining

Before calling for dishwasher repair, homeowners can try these safe troubleshooting steps:

1. Make sure the cycle finished and try a cancel/drain reset.
2. Clean the dishwasher filter.
3. Check the sump area for food, glass, or debris.
4. Inspect the garbage disposal connection.
5. Clean the air gap if the sink has one.
6. Check the drain hose for kinks, clogs, or poor routing.
7. Run a hot cleaning cycle for grease and buildup.

After 10 years of repairing appliances in Atlanta, Alex’s biggest advice is to just start simple. He says that while a dishwasher that is not draining may seem like a major problem, in many cases, it was just a blocked filter, clogged drain path, disposal issue, or an installation problem. Checking those areas first can save time, prevent unnecessary part replacement, and help the homeowner know when it is time to call a professional.

Frequently Asked Questions About a Dishwasher Not Draining