If your dishwasher finishes a cycle but leaves water sitting at the bottom, it can be frustrating and unhygienic. Standing water can lead to bad smells and prevent your dishes from being cleaned properly.

The good news is that most drainage problems are caused by simple issues such as blockages or minor component faults. In many cases, you can identify and fix the problem without needing to replace the appliance.

In this guide we explain the most common reasons a dishwasher is not draining and what you can do to fix it.

1. A Blocked Dishwasher Filter

The most common cause of a dishwasher not draining is a blocked filter.

Dishwashers have filters designed to catch food particles and debris. Over time these can become clogged and restrict water flow.

Signs this is the problem

• Water pooling at the bottom of the dishwasher
• Food debris left on dishes
• Slow drainage after a cycle

How to fix it

• Remove the bottom rack
• Locate and remove the filter
• Rinse it under warm water
• Remove any trapped debris

Cleaning the filter regularly can prevent most drainage issues.

2. A Blocked or Kinked Drain Hose

The drain hose carries waste water from the dishwasher to the sink drain.

If the hose becomes blocked, bent, or twisted, water may not be able to exit the appliance properly.

What to check

• Ensure the hose is not kinked behind the unit
• Check for blockages inside the hose
• Confirm it is connected correctly to the drain

Straightening or clearing the hose can often restore proper drainage.

3. A Blocked Sink Waste or Drain

Sometimes the issue is not the dishwasher itself but the sink drain or waste pipe.

If the pipe connected to the dishwasher is blocked, water cannot flow away properly.

Signs

• Water backing up into the sink
• Slow draining in the sink
• Gurgling sounds from the pipes

Clearing the household drain may solve the problem.

4. A Faulty Drain Pump

The drain pump is responsible for pushing water out of the dishwasher.

If the pump becomes blocked or worn out, it may not be able to remove water effectively.

Symptoms of a pump issue

• A humming or buzzing noise
• Water remaining after the cycle
• The dishwasher stopping mid-cycle

If the pump is faulty, replacing it is often the best solution.

5. Food Debris Blocking the Pump

Small pieces of food, glass, or debris can sometimes get past the filter and block the pump.

This can prevent the pump from working properly and stop water from draining.

What to do

• Turn off and unplug the dishwasher
• Check for debris around the pump area
• Carefully remove any obstructions

6. A Faulty Check Valve

Some dishwashers include a check valve that prevents water from flowing back into the machine.

If this valve becomes stuck or damaged, water may remain inside the dishwasher.

Possible signs

• Water draining slowly
• Water flowing back into the dishwasher
• Inconsistent drainage performance

Replacing the valve may be necessary if it is faulty.

7. Incorrect Installation

If the dishwasher has been recently installed, improper setup can cause drainage problems.

Things to check

• The drain hose is positioned correctly
• The hose has a proper loop to prevent backflow
• The connection to the sink drain is secure

Incorrect installation can prevent proper water flow.

When Replacement Parts May Be Needed

If cleaning and basic checks do not resolve the issue, some components may need replacing.

Common parts linked to dishwasher drainage problems include:

• drain pumps
• filters
• drain hoses
• check valves

Replacing a worn or faulty part can restore proper performance.

You can find a wide range of dishwasher spare parts from Yourspares for many appliance brands.

Preventing Dishwasher Drain Problems

Regular maintenance can help prevent drainage issues and keep your dishwasher running efficiently.

Helpful tips

• Clean the filter regularly
• Remove food scraps before loading dishes
• Avoid overloading the dishwasher
• Check hoses occasionally for blockages
• Run cleaning cycles periodically

Final Thoughts

If your dishwasher is not draining, the cause is often a blockage or a minor component issue. By checking the filter, hose, and pump, you can usually identify the problem quickly.

Fixing the issue early can prevent further damage and keep your dishwasher working effectively.

If your dishwasher is not draining and your dishes are also coming out dirty, the issue may be affecting overall performance. See our guide on dishwasher not cleaning properly and how to fix it.

If no water is entering your dishwasher at all, the problem may be related to the water supply. Read our guide on dishwasher not filling with water and how to fix it.