How to Fix a Dishwasher Not Draining

How to Fix a Dishwasher Not Draining

A dishwasher that won't drain is one of the most common dishwasher problems. Standing water left in the bottom of the tub at the end of a cycle is usually caused by one of a small number of issues, most of which you can diagnose and fix yourself without calling a technician. This guide walks you through the most common causes and how to fix them.

Why Is There Water Left in My Dishwasher?

At the end of a wash cycle, the dishwasher drain pump forces water out through the drain hose into your kitchen drain or garbage disposal. If water isn't clearing, something in that pathway is blocked or not working. The most common causes are:

1. Blocked or dirty filter
2. Kinked or blocked drain hose
3. Blocked air gap (if fitted)
4. Blocked garbage disposal inlet (if connected)
5. Faulty drain pump
6. Faulty drain solenoid

Step 1: Clean the Filter

This is the most common cause of poor draining in modern dishwashers, and the easiest to fix. Most dishwashers made in the last 15 years have a self-clean filter system at the bottom of the tub that traps food particles.

1. Remove the bottom rack
2. Locate the filter assembly — usually a cylindrical filter surrounded by a flat mesh filter at the base of the tub
3. Turn the cylindrical filter anti-clockwise and lift it out, then lift the flat mesh filter
4. Rinse both under warm running water, using a soft brush to remove grease and debris
5. Refit both filters and check the drain runs clear on the next cycle

Filters should be cleaned every 1–4 weeks depending on how heavily the dishwasher is used.

Step 2: Check the Drain Hose

The drain hose runs from the dishwasher to your sink drain or garbage disposal under the sink. Check for:

• Kinks: Pull the dishwasher forward slightly to inspect the hose run. A sharp bend will restrict flow.
• Blockages: Disconnect the hose end at the sink drain (have a bucket ready) and check for obstructions. Run water through the hose to confirm it's clear.
• Incorrect installation height: The drain hose should loop up high under the counter before dropping to the drain connection — this high loop prevents backflow. Without it, dirty water can siphon back into the dishwasher.

Step 3: Check the Air Gap (If Fitted)

Some installations include an air gap — a small chrome fitting mounted on the sink or benchtop near the tap. Unscrew the cap and clean out any debris that has built up inside.

Step 4: Check the Garbage Disposal (If Connected)

If your dishwasher drains into a garbage disposal unit, make sure:

• The disposal isn't full of food waste — run it to clear it
• If the disposal is new, check that the knockout plug inside the dishwasher inlet has been removed (this is a common installation error)

Step 5: Test the Drain Pump

If the above steps don't resolve the problem, the drain pump may be faulty. Signs of a faulty pump include:

• No sound of draining at all during the drain cycle
• A humming noise during drain but no water movement
• Error codes on the display (refer to your dishwasher's manual)

Testing and replacing a drain pump requires accessing the base of the dishwasher and is usually best left to a technician unless you are comfortable with appliance repairs.

When to Call a Technician

If cleaning the filter and checking the hose and disposal don't fix the problem, it's time to call a qualified appliance technician. The issue is likely an internal component — drain pump, drain solenoid or main control board — that needs professional diagnosis and repair.

Need a New Dishwasher?

If your dishwasher is more than 8–10 years old and has drainage or other ongoing issues, replacement may be more cost-effective than repair. Oceania Appliances stocks a wide range of Bosch, Fisher & Paykel, Samsung and AEG dishwashers with delivery across Sydney.

• Showroom: 2/14 Centre Place, Wetherill Park NSW 2164
• Phone / WhatsApp: 0422 489 492
• Email: support@oceaniaappliances.com.au