How to Fix a Dishwasher That Is Not Draining Properly

Few things are more frustrating than opening your dishwasher after a cycle and finding a pool of dirty water at the bottom. A dishwasher that won't drain is a common problem, but in many cases it has a simple cause you can fix yourself — without calling a technician.

This guide walks you through the most common reasons a dishwasher won't drain and what to do about each one.

Step 1: Check the Filter

The most common cause of a dishwasher not draining is a clogged filter. Modern dishwashers have a removable filter at the bottom of the tub that traps food particles. If it's not cleaned regularly, it blocks water from draining.

To clean the filter: remove the bottom rack, twist or unclip the filter assembly, rinse it under running water and use a soft brush to remove debris. Reinstall and run a cycle to see if draining improves.

Step 2: Inspect the Drain Hose

The drain hose runs from the dishwasher to your under-sink plumbing. If it's kinked, clogged or not positioned correctly, water can't drain. Check for bends in the hose and clear any blockages. The hose should loop up high under the sink before connecting to the drain — this loop prevents backflow.

Step 3: Check the Air Gap or Garbage Disposal

If your dishwasher connects to a garbage disposal, make sure the disposal is clear and that the knockout plug was removed when it was installed. A blocked disposal will prevent the dishwasher from draining. If you have an air gap fitting on your sink, check if it's clogged.

Step 4: Check the Drain Pump

The drain pump pushes water out of the dishwasher. If it's blocked by glass, a bone or other debris, it can't operate. Accessing the drain pump depends on your model — check your manual for instructions. Clear any obstruction carefully.

Step 5: Check the Door Latch and Cycle Completion

Occasionally a dishwasher won't drain because the cycle didn't complete properly. Make sure the door closed fully during the cycle and try running a drain-only or quick cycle.

When to Call a Technician

If none of the above steps resolve the issue, the drain pump motor may have failed — this is a repair that requires a qualified appliance technician.

Prevent Drainage Issues Going Forward

• Clean the filter every 2–4 weeks
• Scrape food off plates before loading
• Run the hot water tap at your sink before starting the dishwasher
• Use quality dishwasher detergent and rinse aid

Need a replacement dishwasher? Oceania Appliances stocks a wide range of Bosch, Fisher & Paykel, Miele and Samsung dishwashers with free delivery across Sydney.