A dishwasher that finishes a cycle with standing water in the bottom is a common household problem. Sometimes the cause is as simple as food debris blocking the filter or drain area. In other cases, the drain hose, air gap, garbage disposal connection or drain pump may need further attention.
A small amount of water in a dishwasher sump can be normal on some models. A large amount of standing water after a completed cycle, however, can indicate that the dishwasher is not draining properly.
Quick Reference — What a Dishwasher Not Draining May Mean
The symptoms can provide useful clues about where to start looking. These are common possibilities, but the exact cause depends on the dishwasher model and installation.
Where Is the Water Collecting?
The location of the standing water can help narrow down the possible cause. Look at the bottom of the dishwasher after the cycle has finished.
Water Covering the Bottom
A significant amount of water remaining after a completed cycle usually means that the dishwasher did not drain normally.
Water Around the Filter
Food particles and debris around the filter or sump area can restrict drainage and should be checked according to the model’s instructions.
Water Returning After Draining
If water drains and later appears again, the drain connection or plumbing may need to be investigated.
Water in the Garbage Disposal
Dishwashers connected to a garbage disposal depend on a properly configured drain connection for normal drainage.
Water With Pump Noise
A humming or running sound without effective drainage can point toward a restriction or drain-pump problem.
Water on the Floor
Water outside the dishwasher should be addressed promptly because continued leaking can damage flooring or cabinetry.
Why Is My Dishwasher Not Draining?
Several components work together to remove water from a dishwasher. A problem anywhere along that path can leave standing water.
1. Clogged Dishwasher Filter
The filter catches food particles and debris before they reach other parts of the drainage system. If the filter becomes heavily clogged, water may drain slowly or remain in the bottom of the dishwasher.
2. Blocked Drain Area
Small pieces of food, glass, labels or other debris can sometimes enter the sump or drain area and restrict water movement.
3. Drain Hose Restriction
A kinked, blocked or incorrectly routed drain hose can interfere with the dishwasher’s ability to discharge water.
Other possible causes
- Clogged air gap
- Garbage disposal connection problem
- Drain pump problem
- Blockage in the drain system
- Incorrect drain hose installation
- Plumbing restriction
- Failed electrical component
- Control or cycle-related issue
Dishwasher Has Standing Water at the Bottom
Seeing water at the bottom of a dishwasher does not always mean that the entire appliance has failed. Some dishwasher designs retain a small amount of water in the sump area.
The concern is when there is enough water to cover the bottom of the tub or the water remains after a completed cycle.
Start by checking the filter and other easily accessible areas recommended by the appliance manufacturer. If the dishwasher still cannot drain, the problem may be deeper in the drainage system.
Signs the drainage problem is more significant
- Standing water remains after every cycle
- Dishwasher drains very slowly
- Water returns after initially draining
- Drain pump makes unusual sounds
- Dishwasher stops before completing the cycle
- Dirty water remains in the tub
Dishwasher Makes Noise but Doesn’t Drain
Hearing the dishwasher’s drain pump operate does not necessarily mean that water is actually leaving the appliance.
Humming Sound
A humming sound can occur when the pump is receiving power but water flow is restricted or the pump is having difficulty operating.
Grinding or Rattling
Unusual mechanical noise may indicate debris or a problem involving the drain pump or another moving component.
Pump Runs but Water Stays
If the pump runs but the water level does not change, the drain path or pump may require further inspection.
Dishwasher Won’t Drain After Installation
If a dishwasher was recently installed and has never drained correctly, the issue may be related to the drain connection or installation rather than a failed appliance component.
Dishwashers can be connected to a sink drain, garbage disposal or other approved drainage configuration. The drain hose must also be routed correctly for the specific installation.
If the appliance is new or was recently moved, review the installation instructions before assuming the dishwasher needs a replacement part.
Installation-related possibilities
- Drain hose incorrectly routed
- Drain connection blocked
- Garbage disposal connection not configured correctly
- Plumbing connection restriction
- Installation-related drainage issue
What You Can Safely Check Yourself
A few basic checks can sometimes resolve a simple drainage problem. Always follow the appliance manufacturer’s instructions for your model.
When to stop troubleshooting
Avoid removing electrical panels, accessing internal components or repeatedly running the dishwasher when water is leaking onto the floor. If the source of the problem is not obvious, professional diagnosis can prevent additional damage.
Dishwasher Drainage Problem Guide
Different symptoms can point toward different parts of the drainage system. Use this table as a starting point when describing the problem.
| Symptom | Possible causes |
|---|---|
| Standing water after cycle | Filter, drain path, drain hose or pump |
| Drains very slowly | Partial blockage, hose restriction or plumbing |
| Pump runs but water stays | Drain restriction or pump problem |
| Water returns later | Drain connection or plumbing issue |
| Dirty water remains | Drainage restriction or incomplete draining |
| Water leaks onto floor | Drainage overflow, hose, seal or other leak source |
When Does a Dishwasher Need Professional Repair?
If cleaning the filter and checking accessible drainage areas does not solve the problem, the dishwasher may need additional diagnosis.
Professional repair may be appropriate when:
- Standing water returns after every cycle.
- The drain pump is noisy or not operating correctly.
- The drain hose or internal drainage system may be blocked.
- The dishwasher leaks onto the floor.
- The dishwasher stops before completing the cycle.
- An electrical or control problem may be involved.
What to tell the technician
- How much water remains in the dishwasher.
- Whether the water is clean or dirty.
- Whether the pump makes noise.
- Whether the dishwasher drains slowly or not at all.
- Whether the problem started after installation or plumbing work.
- Any error code shown on the control panel.
Other Common Dishwasher Problems
A drainage problem is not always the only symptom. If your dishwasher is having other problems, note them when scheduling service because they can help with diagnosis.
Dishwasher Not Heating
If dishes remain cold or wet after a cycle, the heating system, control or another component may require diagnosis.
Dishwasher Leaking
Water on the floor can have several possible causes, including drainage overflow, hoses, seals or other components.
Dishwasher Not Cleaning
Poor cleaning can be related to spray arms, filters, water flow, detergent or other components.
Dishwasher Making Noise
Grinding, rattling or unusual humming can indicate debris or a mechanical component that needs attention.
Dishwasher Stops Mid-Cycle
A dishwasher that stops unexpectedly may have a drainage, heating, electrical or control-related problem.
Dishwasher Shows an Error Code
Error codes vary by model. Record the exact code before scheduling service because it can provide a useful diagnostic clue.
Related Appliance Repair Resources
If your dishwasher is experiencing a drainage problem or another issue, these pages may help you learn more about available repair services.
Dishwasher Not Draining FAQ
Why is my dishwasher not draining?
Common possibilities include a clogged filter, blocked drain area, restricted drain hose, air gap or garbage disposal connection, plumbing restriction, or a problem with the drain pump.
Why is there standing water in the bottom of my dishwasher?
A small amount of water can remain in the sump area on some dishwasher models. If there is significant standing water after a completed cycle, the dishwasher may not be draining properly.
Can a clogged dishwasher filter stop it from draining?
Yes. A heavily clogged filter can restrict water flow and contribute to slow or incomplete drainage. Check and clean the filter according to your dishwasher manufacturer’s instructions.
Why does my dishwasher make a noise but not drain?
The drain pump may be operating but water may still be restricted by a blockage, hose problem or another issue in the drainage system. A failing pump is another possibility.
Why does water come back into my dishwasher after it drains?
Water returning after drainage can indicate a problem with the drain connection, hose routing or connected plumbing. The exact cause depends on the installation.
Should I run my dishwasher again if it has standing water?
If there is a large amount of standing water, repeatedly running the dishwasher may not solve the underlying problem. Check the accessible filter and drainage areas first, and arrange service if the dishwasher still cannot drain.
Can a garbage disposal cause a dishwasher not to drain?
Yes. Dishwashers connected to a garbage disposal depend on a properly configured drain connection. A restriction in the connection or related plumbing can interfere with drainage.
Is a dishwasher that won’t drain an emergency?
A dishwasher that simply leaves standing water is usually not an emergency, but a dishwasher that is actively leaking onto the floor should be addressed promptly to reduce the risk of water damage.
When should I call a dishwasher repair technician?
Professional service is appropriate when basic checks do not resolve the problem, standing water keeps returning, the drain pump is making unusual noises, the dishwasher is leaking, or an internal drainage or electrical component may be involved.
Dishwasher Still Won’t Drain?
If you’ve checked the accessible filter and drainage areas and your dishwasher still leaves standing water, the problem may require a closer inspection. North Appliance Service provides dishwasher repair throughout King County and Snohomish County.
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