Dishwasher Not Draining? Troubleshooting Guide and Common Causes

A dishwasher that won’t drain is one of the most common appliance problems homeowners face. You open the door after a cycle and find a pool of dirty water sitting at the bottom of the tub. The good news is that most dishwasher draining problems can be diagnosed quickly, and many fixes are inexpensive.

Table of Contents

• Common Causes of a Dishwasher Not Draining
• 1. Clogged Filter or Fine Mesh Screen
• 2. Blocked Drain Hose
• 3. Faulty Drain Pump
• 4. Garbage Disposal or Air Gap Blockage
• 5. Broken Check Valve or Non-Return Valve
• 6. Failed Drain Solenoid or Wash Pump Assembly
• 7. Control Board or Timer Failure
• Brand-Specific Dishwasher Not Draining Issues
• How to Troubleshoot a Dishwasher Not Draining: Step by Step
• When to Call a Professional for Dishwasher Repair
• Dishwasher Repair Costs in San Diego
• Preventing Future Dishwasher Draining Problems
• Frequently Asked Questions

911 Appliance Repair has been fixing dishwashers in San Diego since 1991. This guide walks through the most common reasons a dishwasher stops draining, how to troubleshoot each one, and when to call a professional.

TL;DR: The most common causes of a dishwasher not draining are a clogged filter, a blocked drain hose, a faulty drain pump, or a garbage disposal connection issue. Most of these can be diagnosed in under 30 minutes. If your dishwasher won’t drain, call 911 Appliance Repair at 800-929-1192 for same-day service in San Diego.

Common Causes of a Dishwasher Not Draining

1. Clogged Filter or Fine Mesh Screen

The filter at the bottom of the dishwasher tub catches food particles, grease, and debris. Over time, it can become completely clogged, blocking water from reaching the drain pump. This is the single most common cause of a dishwasher not draining, and it is also the easiest to fix.

How to check: Remove the lower dish rack. Twist and lift the filter assembly at the bottom of the tub. Rinse it under running water and scrub with a soft brush to remove buildup. Check the area underneath the filter for any debris. Reinstall the filter and run a short cycle to see if the dishwasher drains.

Important: If you have never cleaned your dishwasher filter, it may be the only problem. Many manufacturers recommend cleaning the filter monthly.

2. Blocked Drain Hose

The drain hose carries water from the dishwasher to the garbage disposal or sink drain. If the hose becomes kinked, crushed, or clogged with food or grease, water cannot flow through it. A blockage in the drain hose is the second most common cause of standing water in a dishwasher.

How to check: Turn off power to the dishwasher. Locate the drain hose, usually running from the bottom of the dishwasher to the garbage disposal or sink drain under the cabinet. Check for kinks or sharp bends. Disconnect the hose at the disposal or sink end and check for blockages. Use a straightened wire hanger or a plumber’s snake to clear any clog.

Warning: Place a bucket under the hose before disconnecting it, as water will spill out.

3. Faulty Drain Pump

The drain pump pushes water out of the dishwasher at the end of each cycle. If the pump motor fails or the impeller inside the pump is broken or jammed by debris, the dishwasher will fill and wash but will not drain.

How to check: Listen for a humming sound at the bottom of the dishwasher during the drain cycle. If you hear humming but no water drains, the pump motor may be seized or the impeller jammed. If you hear nothing, the pump motor may have failed or may not be receiving power. Access the drain pump by removing the lower access panel and test the pump motor with a multimeter for continuity.

Cost to replace: A drain pump typically costs $40 to $120 for the part, plus labor. Total repair cost is usually $150 to $300.

4. Garbage Disposal or Air Gap Blockage

If your dishwasher drains through a garbage disposal, a clog in the disposal inlet can block the dishwasher drain line. This often happens in newly installed disposals where the knockout plug was not removed. If your dishwasher drains through an air gap mounted on the sink, the air gap itself can become clogged with food debris.

How to check: If your dishwasher connects to a garbage disposal, disconnect the drain hose from the disposal inlet and check for blockage. If the disposal was recently installed, make sure the knockout plug inside the disposal inlet was punched out. If you have an air gap, remove the chrome cap and check the plastic interior for debris.

5. Broken Check Valve or Non-Return Valve

Many dishwashers have a check valve, also called a non-return valve or flapper valve, that prevents dirty water from flowing back into the dishwasher after it drains. If this valve is stuck closed or broken, water cannot exit the dishwasher. If it is stuck open, dirty water flows back in after draining.

How to check: Locate the check valve in the drain path, usually near the pump outlet or where the drain hose connects to the pump. Remove it and inspect for debris, warping, or damage. If the valve is stuck or damaged, replace it.

6. Failed Drain Solenoid or Wash Pump Assembly

Some dishwashers, particularly older models, use a drain solenoid to redirect water from the wash cycle to the drain cycle. If the solenoid fails, the dishwasher washes but does not drain. On newer models, a single pump assembly handles both washing and draining, and a failure in the assembly can prevent draining.

How to check: Access the drain solenoid (if equipped) and test it with a multimeter for continuity. If the solenoid shows no continuity or is visibly damaged, replace it. If your dishwasher uses a combined wash and drain pump, the entire assembly may need replacement.

7. Control Board or Timer Failure

The electronic control board or mechanical timer sends power to the drain pump at the appropriate point in the cycle. If the control board fails, the dishwasher may complete the wash cycle but never enter the drain cycle. This is less common than the other causes but does happen, especially on older mechanical timer models.

How to check: This requires advanced diagnosis. If the drain pump, filter, drain hose, and check valve all test good but the dishwasher still does not drain, the control board or timer may not be sending power to the pump. A technician can test for voltage at the pump during the drain cycle to confirm.

Brand-Specific Dishwasher Not Draining Issues

Bosch Dishwasher Not Draining

Bosch dishwashers are known for a fine mesh filter that clogs more easily than other brands. The drain pump on Bosch models is located at the bottom left of the tub. Bosch dishwashers also use a check valve in the drain hose that can stick. If your Bosch dishwasher is not draining, start by cleaning the filter thoroughly, then check the drain pump impeller for debris.

Whirlpool Dishwasher Not Draining

Whirlpool dishwashers commonly fail to drain due to a clogged chopper blade assembly. The chopper blade chops food particles before they reach the pump, and if it becomes jammed, water cannot drain. The drain pump itself can also fail. Check the chopper assembly first, then test the drain pump.

GE Dishwasher Not Draining

GE dishwashers often have drain problems caused by a clogged piston and nut assembly in the drain path. This small component can become blocked with food or mineral buildup. GE models also use a drain solenoid on some models that can fail. Check the piston assembly first, then test the solenoid if equipped.

Samsung Dishwasher Not Draining

Samsung dishwashers commonly fail to drain due to a clogged mesh filter or a blocked drain hose. The drain pump on Samsung models is accessible from the bottom front. Samsung dishwashers may display error codes like 9E or 9C1 when a drain problem is detected.

LG Dishwasher Not Draining

LG dishwashers use a drain pump that can fail or become jammed by debris. The check valve in the drain hose can also stick. LG dishwashers may display an OE error code when a drain problem is detected, which means the dishwasher detected water still in the tub after the drain cycle.

KitchenAid Dishwasher Not Draining

KitchenAid dishwashers, which are manufactured by Whirlpool, share the same common drain problems. The chopper blade assembly can jam, the drain pump can fail, and the filter can clog. Check the filter first, then the chopper assembly, then the drain pump.

Frigidaire Dishwasher Not Draining

Frigidaire dishwashers commonly fail to drain due to a clogged filter screen or a faulty drain pump. The drain pump on Frigidaire models is located at the bottom of the tub. Check the filter first, then test the drain pump for continuity.

Maytag Dishwasher Not Draining

Maytag dishwashers, also manufactured by Whirlpool, share the same drain issues. The chopper assembly, drain pump, and filter are the most common culprits. Check the filter first, then the chopper, then the drain pump.

Kenmore Dishwasher Not Draining

Kenmore dishwashers are manufactured by Whirlpool or Frigidaire depending on the model. Check the model number to determine the manufacturer, then follow the corresponding troubleshooting steps above.

Miele Dishwasher Not Draining

Miele dishwashers use a high-quality drain pump that rarely fails, but the filter system is fine and clogs easily. The non-return valve in Miele dishwashers can also stick. Clean the filter thoroughly, then check the non-return valve before testing the pump.

How to Troubleshoot a Dishwasher Not Draining: Step by Step

1. Check for standing water: If there is water in the bottom of the tub, note how much. A small amount is normal. A large pool means the dishwasher is not draining.
2. Clean the filter: Remove the lower rack, take out the filter, and clean it thoroughly under running water.
3. Check the garbage disposal: Run the disposal to clear any blockage. If the disposal was recently installed, verify the knockout plug was removed.
4. Check the air gap: If you have an air gap on the sink, remove the cap and clean out any debris.
5. Inspect the drain hose: Turn off power, locate the drain hose under the sink, check for kinks, and clear any blockage.
6. Test the drain pump: Listen for humming during the drain cycle. If you hear nothing, test the pump with a multimeter for continuity.
7. Check the check valve: Inspect the check valve in the drain path for debris or damage.
8. Test the drain solenoid: If your dishwasher has a separate drain solenoid, test it for continuity.

If you are not comfortable working with electrical components or disassembling your dishwasher, call a professional. Dishwasher repair involves water and electrical components in close proximity, which requires safe handling.

When to Call a Professional for Dishwasher Repair

Call 911 Appliance Repair if:

• You have cleaned the filter and checked the drain hose but the dishwasher still will not drain
• You do not have a multimeter or are not comfortable testing electrical components
• The drain pump is humming but not pumping, which may indicate a seized motor
• You suspect a control board or timer problem
• Water is leaking from the bottom of the dishwasher
• You want the repair done quickly with a warranty

Dishwasher Repair Costs in San Diego

Part	Part Cost	Total Repair Cost (Parts + Labor)
Filter cleaning	$0	DIY
Drain hose	$15 to $35	$100 to $180
Drain pump	$40 to $120	$150 to $300
Check valve	$15 to $40	$120 to $220
Drain solenoid	$20 to $50	$130 to $250
Chopper blade assembly	$20 to $50	$130 to $250
Control board	$100 to $300	$250 to $500

At 911 Appliance Repair, our $49.95 house call is free when you approve the repair. We provide upfront pricing before any work begins, and every repair is backed by a 1-year warranty on parts and labor.

Preventing Future Dishwasher Draining Problems

• Scrape plates before loading. Large food particles can clog the filter and drain pump. Scrape food into the trash before loading dishes.
• Clean the filter monthly. Remove the filter and rinse it under running water. Use a soft brush for stubborn buildup.
• Run hot water before starting the dishwasher. Run the kitchen sink faucet until the water is hot, then start the dishwasher. This helps dissolve grease and prevents buildup in the drain hose.
• Use the right detergent. Use dishwasher detergent, not dish soap. Dish soap creates excessive suds that can interfere with draining.
• Run a cleaning cycle monthly. Use a dishwasher cleaner or run an empty cycle with a cup of white vinegar in the top rack to remove grease and mineral buildup.

If your dishwasher is not draining and you need professional repair in San Diego, call 911 Appliance Repair at 800-929-1192. Same-day service is available for most calls, and we stock common dishwasher drain parts in our service trucks for single-visit repairs.

Frequently Asked Questions

Why is there water at the bottom of my dishwasher?

A small amount of water, usually less than a cup, at the bottom of the dishwasher after a cycle is normal. It keeps the seals moist. If there is a large pool of dirty water, the dishwasher is not draining. The most common causes are a clogged filter, a blocked drain hose, or a faulty drain pump.

How do I know if my dishwasher drain pump is bad?

Listen for a humming sound during the drain cycle. If you hear humming but no water drains, the pump impeller may be jammed. If you hear nothing, the pump motor may have failed. Test the pump with a multimeter for continuity. If there is no continuity, the pump needs replacement.

Can a clogged garbage disposal cause my dishwasher not to drain?

Yes. If your dishwasher drains through a garbage disposal, a clog in the disposal inlet can block the dishwasher drain line. Run the disposal to clear any blockage. If the disposal was recently installed, check that the knockout plug inside the disposal inlet was removed.

How much does it cost to fix a dishwasher that won’t drain?

Most dishwasher drain repairs cost between $120 and $300, depending on the part. A drain hose replacement is the least expensive at $100 to $180, while a drain pump replacement costs $150 to $300. At 911 Appliance Repair, our $49.95 house call is free with repair.

Is it worth fixing a dishwasher that won’t drain?

In most cases, yes. The most common fixes (filter cleaning, drain hose, drain pump) cost $100 to $300, which is far less than buying a new dishwasher ($400 to $1,200). If your dishwasher is less than 10 years old and the repair costs less than half the price of a new unit, repair is the better choice.