Opening the dishwasher after a cycle and finding a pool of dirty water sitting in the bottom is frustrating, especially when everything else seems to be working normally.
The good news is that a dishwasher that won’t drain does not necessarily mean the machine needs to be replaced. In many cases, the problem is caused by something relatively simple, such as food debris blocking the filter, a clogged drain hose, or a problem with the way the dishwasher connects to the sink or garbage disposal.
Before calling for a repair, there are several things you can safely check yourself.
Why is my dishwasher not draining?
A dishwasher that won’t drain usually has a restriction somewhere in its drainage system. The most common places to look are the filter, the sump area underneath the filter, the drain hose, and the connection between the dishwasher and your sink or garbage disposal.
A drain pump that is jammed or failing can also prevent water from leaving the machine. Less commonly, the problem can involve an electrical component, wiring, or the dishwasher’s control system.
The first thing to determine is whether you are dealing with a small amount of residual water or a genuine drainage problem.
Is it normal to have some water in the bottom of a dishwasher?
A small amount of water in the lowest part of the dishwasher can be normal on some models. The sump area is designed to retain a small amount of water, so seeing a little moisture below the filter does not automatically mean something is wrong.
The situation is different if you open the dishwasher and see a noticeable pool of standing water covering the bottom, particularly if the water remains there after a completed cycle.
If there is enough water that you can see it sitting above the filter area, or the water level is rising instead of disappearing, the dishwasher likely has a drainage problem that needs attention.
Start with the dishwasher filter
The filter is one of the first things worth checking because it is designed to catch food particles and other debris before they can reach the drain system.
Over time, grease, food particles, labels, seeds and other debris can accumulate around the filter. If the filter becomes heavily blocked, water may drain slowly or stop draining altogether.
Turn off the dishwasher and remove the lower rack so you can access the filter. On many models, the filter can be removed by twisting or lifting it, although the exact procedure varies by manufacturer.
Rinse the filter thoroughly under running water. If debris is stuck to the mesh, use a soft brush to loosen it rather than aggressively scraping or damaging the filter.
While the filter is removed, look into the area underneath it. This is important because cleaning the filter alone will not necessarily solve the problem if food or another object has already made its way into the sump.
Manufacturers including Whirlpool, Maytag and Samsung recommend checking the filter and drain area when a dishwasher is experiencing drainage problems.
Look for debris underneath the filter
If cleaning the filter doesn’t solve the problem, the next place to investigate is the sump or drain area beneath it.
Small objects can occasionally end up in this area, particularly if dishes were loaded with food particles or an object accidentally fell into the bottom of the dishwasher.
Depending on the dishwasher, you may find pieces of food, broken glass, labels, toothpicks or other debris interfering with the drainage path.
Use caution when inspecting this area. Broken glass can be difficult to see in standing water, so don’t reach blindly into the sump with your bare hand.
If you can clearly see an accessible piece of debris, remove it carefully. Do not disassemble the dishwasher beyond what your owner’s manual specifically permits.
After removing any obvious obstruction, reinstall the filter and run a short cycle to see whether the water drains normally.
Check the drain hose
If the filter and sump are reasonably clean, the drain hose is another important place to look.
The hose carries wastewater from the dishwasher to the sink drain or garbage disposal. If it becomes kinked, compressed, blocked or improperly positioned, water may have difficulty leaving the dishwasher.
Look underneath the sink for the dishwasher drain hose. Make sure it isn’t sharply bent or crushed against the cabinet.
A hose can look fine from the outside while still having a restriction inside, but visible kinks or compression are an easy problem to identify and correct.
The way the hose is routed also matters. Dishwashers generally need the drain hose installed with an appropriate high loop or air-gap arrangement to help prevent wastewater from flowing back into the dishwasher. The exact setup depends on the dishwasher and local plumbing requirements.
Check the sink and garbage-disposal connection
Sometimes the dishwasher itself isn’t the real problem.
Many dishwashers drain into the kitchen sink’s plumbing or connect directly to a garbage disposal. If that connection is blocked, the dishwasher may be unable to drain even though its filter and pump are working correctly.
Run some water into the sink and make sure the sink itself drains normally. If the sink is also draining slowly, the plumbing may be contributing to the problem.
If your dishwasher drains through a garbage disposal, check that the disposal is draining properly as well.
There is another particularly important possibility if the garbage disposal was recently installed or replaced: the dishwasher inlet may still have its knockout plug installed. That plug needs to be removed when the dishwasher drain hose is connected to the disposal. If it isn’t, the dishwasher can run normally but have nowhere for its wastewater to go.
What if the dishwasher drains, but the water keeps coming back?
If the dishwasher initially drains but later has water sitting in the bottom again, that points toward a slightly different problem.
Wastewater can sometimes flow backward into the dishwasher when the drain hose is improperly routed or the sink or disposal connection is allowing backflow.
This is one reason the drain hose’s installation matters. A properly configured high loop or air gap helps keep wastewater from traveling back toward the dishwasher.
If the dishwasher is relatively new or the problem started after plumbing work under the sink, pay particular attention to the drain hose routing and connections.
Listen to the dishwasher when it tries to drain
If the dishwasher still contains water after you’ve checked the filter, sump and drain hose, pay attention to what you hear when it enters the drain portion of a cycle.
A steady humming or buzzing sound without much water movement can indicate that something is interfering with the drain pump or its impeller.
A grinding sound can suggest that a hard object, such as a small piece of glass or another foreign object, has reached the pump area.
On the other hand, if the dishwasher is completely silent when it should be draining, the problem may be more than a simple blockage. Depending on the model, the drain pump, wiring, control board or another electrical component could be involved.
This is where troubleshooting becomes more model-specific. Some manufacturers provide diagnostic procedures or error codes that can help identify a drainage problem. Samsung, for example, uses codes such as 5C, SC, 5E and SE on certain models to indicate drainage-related problems.
What if the dishwasher is draining very slowly?
A dishwasher doesn’t necessarily have to be completely full of water to have a drainage problem.
If the water eventually disappears but takes much longer than usual, there may still be a partial restriction somewhere in the system.
A dirty filter is an obvious possibility. Debris in the sump or drain pump can also restrict water flow, while a partially obstructed or improperly routed drain hose can slow the process.
The difference between slow drainage and a complete blockage can also provide a useful clue. If the dishwasher is gradually emptying, water is making it through the drainage system, but something may be restricting the flow.
Cleaning the filter and inspecting the accessible drain area is a sensible first step before moving on to the hose and plumbing connection.
Don’t pour chemical drain cleaner into the dishwasher
It may be tempting to reach for a chemical drain opener when you see standing water, but that’s not a good solution for a dishwasher.
Dishwasher drainage problems are usually caused by a specific obstruction, hose issue, plumbing connection or mechanical problem. Chemical drain cleaners can also create a safety hazard when you later work on the appliance.
Instead, remove standing water manually if necessary and investigate the actual cause of the blockage.
Whirlpool specifically advises against using chemical drain-opening products in a dishwasher.
How to remove standing water from a dishwasher
If there is a significant amount of water in the bottom, remove enough of it to safely inspect the filter and drain area.
A cup can be used to scoop out larger amounts of water. A turkey baster or similar tool can help remove the remaining water around the filter area.
Once the water level is low enough, remove and clean the filter and inspect the accessible sump area for obvious debris.
Before working around internal dishwasher components, disconnect power according to the manufacturer’s instructions. If your dishwasher is hardwired, this may mean switching off the appropriate circuit breaker.
When the drain pump may be the problem
If the filter is clean, the drain area is clear, the hose isn’t kinked and the sink or disposal connection appears normal, the drain pump becomes a stronger suspect.
The pump is responsible for moving wastewater out of the dishwasher. A foreign object can sometimes interfere with its impeller, or the pump itself can eventually fail.
The symptoms can vary.
A dishwasher that makes a humming noise but doesn’t move water may have something obstructing the pump. Grinding or unusual noises can also indicate debris around the pump or impeller.
If the dishwasher makes no sound from the pump at all when it should be draining, an electrical or control problem is also possible.
Accessing the drain pump can require removing panels or other components, and the procedure varies considerably between dishwasher models. If your owner’s manual doesn’t provide a straightforward procedure, this is a good point to consider professional service rather than taking the machine apart blindly.
When should you call a professional?
You can safely troubleshoot many common dishwasher drainage problems without replacing parts, but not every situation is a DIY repair.
Consider calling an appliance technician if you’ve cleaned the filter, checked the accessible drain area, inspected the hose and confirmed that the sink or garbage disposal is draining normally, but the dishwasher still won’t empty.
Professional help is particularly appropriate if you suspect a failed drain pump, damaged wiring, a control-board problem or another internal component.
Stop troubleshooting and disconnect power if you notice a burning smell, damaged wiring, repeated breaker trips or other signs of an electrical problem.
It’s also worth checking your dishwasher’s owner’s manual before removing panels or internal components. Different manufacturers and models can use very different drain systems.
How to prevent dishwasher drainage problems
The easiest way to deal with a clogged dishwasher is to prevent the buildup from becoming severe in the first place.
Clean the dishwasher filter regularly. How often it needs cleaning depends on how frequently the dishwasher is used and how much food debris ends up on the dishes.
You should also avoid allowing large pieces of food, bones, labels and other debris to enter the dishwasher. Modern dishwashers don’t require dishes to be completely spotless before loading, but scraping off large food particles can reduce the amount of material that reaches the filter and drain system.
It’s also worth occasionally checking underneath the sink. Make sure the dishwasher drain hose isn’t being compressed by stored items and that its connections remain secure.
If the dishwasher or garbage disposal has recently been installed, replaced or serviced, check the drain connection carefully if drainage problems begin immediately afterward.
Frequently asked questions
Why is there standing water in the bottom of my dishwasher?
The most common causes include a clogged filter, debris in the drain area, a blocked or kinked drain hose, a problem with the sink or garbage-disposal connection, or a drain pump problem.
A small amount of water in the sump area can be normal on some dishwashers, but a substantial pool of water remaining after a cycle usually indicates a drainage issue.
Why is my dishwasher not draining but the sink is?
A normally draining sink doesn’t rule out a dishwasher-specific problem. The dishwasher filter, sump, drain hose, pump or connection between the dishwasher and sink plumbing could still be blocked.
Start by checking the dishwasher filter and accessible drain area, then inspect the drain hose underneath the sink.
Why does my dishwasher drain slowly?
Slow drainage can be caused by a partially clogged filter, debris in the sump or drain pump, a restricted drain hose, or a problem with the plumbing connection.
If the dishwasher eventually drains but takes significantly longer than it used to, look for a partial restriction rather than assuming the pump has completely failed.
Why does my dishwasher have water in it after every cycle?
If there is more than a small amount of residual water, the dishwasher may not be completely draining. A recurring problem can come from a filter restriction, drain hose issue, plumbing connection, drain pump or improper hose routing.
If the problem started after an installation or plumbing change, check the drain hose configuration and connections first.
Can I use Drano or drain cleaner in my dishwasher?
No. Chemical drain cleaners are not an appropriate solution for a dishwasher drainage problem. They can create a safety hazard and may damage components.
It’s better to identify and remove the actual obstruction or have the dishwasher professionally diagnosed.
The bottom line
When a dishwasher won’t drain, don’t immediately assume that the pump has failed.
Start with the simplest possibilities. Clean the filter, inspect the area underneath it, look for obvious debris, and check the drain hose underneath the sink. Make sure the sink or garbage disposal is draining normally and that the dishwasher’s drain connection is properly configured.
Those checks can resolve many drainage problems without replacing a part.
If the dishwasher still won’t drain after those steps, especially if it makes unusual noises or doesn’t appear to activate the drain pump at all, the problem may require a closer look at the pump or electrical components.
The important thing is to diagnose the cause before replacing parts. A dishwasher that won’t drain can have a surprisingly simple explanation.
SOURCES: Whirlpool, Samsung, Maytag, LG, and Frigidaire dishwasher troubleshooting and drainage guidance.
