Dishwasher Not Draining

Finding standing water in the bottom of your dishwasher is frustrating – but it's often a simple blockage you can fix yourself.

Check These Things First

1. The Filter

This is the most common cause of drainage problems. Food debris builds up and blocks water flow.

How to check:

1. Remove the lower rack
2. Locate the filter at the bottom (usually a cylindrical mesh)
3. Twist and lift to remove
4. Clean under running water
5. Use an old toothbrush for stubborn debris

2. The Drain Hose

The hose that connects to your sink waste can get kinked or blocked.

How to check:

• Pull the dishwasher out slightly (careful not to damage the hose)
• Look for kinks, bends, or crushing
• Straighten any kinks
• If detachable, check inside for blockages

3. The Sink Waste Connection

If your dishwasher drains into the sink waste, a blocked sink will stop your dishwasher draining.

How to check:

• Does your sink drain slowly? If so, clear it first
• Check the spigot where the hose connects isn't blocked
• Run hot water through the sink to clear any grease

4. The Air Gap (If Fitted)

Some installations have an air gap on the worktop near the sink.

How to check:

• Remove the cap and clean inside
• This prevents backflow and can get blocked

Still Not Draining?

If you've checked all the above and water still won't drain, the issue is likely:

Faulty Drain Pump

The pump pushes water out of the dishwasher. If it fails, water stays inside.

Signs:

• No humming sound during drain cycle
• Water doesn't move at all
• Error codes like E21, E22, or F5

DIY fix? No – the pump needs to be replaced by an engineer.

Blocked Pump Impeller

Small objects (glass shards, food, packaging) can jam the pump impeller.

Signs:

• Pump hums but water doesn't drain
• Grinding noise

DIY fix? Sometimes – if you can access the pump. Otherwise call an engineer.

Control Board Issue

The main control board tells the pump when to run. If it's faulty, the pump may never activate.

Signs:

• Random cycle problems
• Other functions also misbehaving

DIY fix? No – requires professional diagnosis.

How to Manually Drain Your Dishwasher

If you need to empty the water before a repair:

1. Place old towels around the base
2. Locate the drain hose (under the sink usually)
3. Disconnect it and let water drain into a bucket
4. Alternatively, use a wet-dry vacuum
5. Soak up remaining water with towels

Prevention Tips

• Scrape plates before loading (no pre-rinse needed)
• Clean the filter monthly
• Run the hot tap before starting a cycle
• Use dishwasher cleaner monthly
• Don't overload – water needs to circulate

Time to Call an Engineer?

If you've checked the filter, hose, and sink connection and still have standing water, get a fixed price quote for professional diagnosis and repair.