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How to unblock a dishwasher and solve all your dishwasher dilemmas

Dishwasher not draining? Plates not coming out clean? Get your dishwasher running smoothly again in no time with our handy guide.

Updated

By Cleanipedia Team

Knowing how to unblock a dishwasher yourself could save you a pricey plumber’s visit. So if you’ve opened the dishwasher to the heart-sinking sight of standing water, don’t reach straight for the phone. Try our simple how-to guide to see if you can sort the problem yourself.

And it doesn’t stop there. Whether you’ve got issues with dishes coming out dirty or you’re worried about strange clanking noises during a cycle, we’ve got some suggestions to help you solve those problems too. So whatever your dishwasher dilemma, read on to get the lowdown on how to fix it.

You will need:

  • Rubber gloves
  • Stiff brush or old toothbrush
  • Old towels
  • Plastic cup or jug
  • A long flexible brush (in some instances)
  • Washing up liquid

How to fix a blocked dishwasher that’s not draining

Water not draining from your dishwasher? How much you can do to clear a blocked dishwasher and how to unblock a dishwasher drain will depend on the make and model of your machine. When following these steps, make sure you’ve got the manufacturer’s manual to hand to help you locate the parts we mention (if you can’t find your manual, it should be available online).

  1. Turn off your dishwasher and take out the baskets

    Before you start, make sure your dishwasher is turned off at the mains. Then remove the baskets (the bits that slide out which hold the items being cleaned).

  2. Remove and unblock the dishwasher drain filter

    A blocked filter is one of the most common reasons for a dishwasher not draining. It’s also an easy problem to fix.

    The filter will be located at the base of your machine, usually below the spray arm. Remove the cover and carefully take out the filter and rinse it under a hot running tap. Then scrub it with a stiff brush or an old toothbrush dipped in hot water mixed with a little washing up liquid.

    Tip: You’ll probably want to don a pair of rubber gloves for this bit. For more, read our guide on how to clean a dishwasher.)

  3. Bail out any remaining water

    If there’s still water in the bottom of the dishwasher, it’s time to start bailing it out with a plastic cup or jug. This will help you to see if there are any blockages in the sump (the hole beneath the filter that leads to the drain).

    Tip: Put some old towels on the floor, as bailing out the water can be messy.

  4. Check the sump for blockages

    Your dishwasher’s manual should show which parts of the sump are accessible and where you can check for other potential obstructions. With any luck, you’ll be able to scoop out the blockage.

  5. Replace the filter and run a short cycle

    Replace the filter and the cover, checking that they’re properly aligned and that the spray arm is rotating freely. Then run a short cycle to see whether or not the water is now draining away.

    Still having problems? Follow the next steps carefully…

  6. Check the kitchen sink waste for blockages

    If you’re still having trouble, you may have a blocked sink on your hands (if your dishwasher waste pipe is connected to the sink waste).

    To sort out a blocked sink, follow our guide to unclogging your sink, then run another short cycle to see if this has resolved the issue.

  7. Check if the waste hose is blocked (if possible)

    (The hose for an integrated dishwasher will be difficult to access. In this instance, you’ll need to skip straight to step 8.)

    If cleaning the filters doesn’t fix the problem and your sink waste isn’t the issue either, it’s time to look at the waste hose at the back of the dishwasher. If it’s squashed or kinked this could stop the wastewater from draining away.

    If the dishwasher is freestanding, isolate the water supply to the machine, then ease the dishwasher away from the wall (you may need another person to help you with this).

    Check that the hose doesn’t have any obvious blocked points or kinks. Correct any bends, and if you find a clog, disconnect the hose, keeping the open end raised. Use a long flexible brush, or squeeze the hose gently, to dislodge it. If you have a garden hose, you could use it at this point to flush water through.

    Reconnect the dishwasher hose securely and when you push your machine back into place, ensure there’s enough room for the hose not to be compressed, allowing it to drain water away freely. Run another short cycle to see if the problem is fixed – and to make sure everything is reconnected correctly.

  8. Call in the experts

    If you’re still facing problems, then now’s the time to call in the professionals.

The above steps should have your dishwasher happily cleaning your dishes again – but to find out how to tackle some other common dishwasher problems, keep reading...

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Dealing with a dishwasher that’s making loud noises

If you’re hearing worrying noises while your dishwasher’s working away, then there are two key things to check:

  • Are dishes touching each other or has a utensil fallen out of the cutlery basket?

If this is the case, you may not have loaded the dishwasher correctly. To prevent it from happening again check out our guide on the best way to load a dishwasher.

  • Is your dishwasher level?

Make sure your dishwasher is positioned on a flat, level surface. If it’s tipping back and forth because of an uneven surface this could be the cause of the noise.

What to do when your dishwasher won’t start

It may seem obvious, but if your dishwasher won’t start, the first thing you should do is make sure the door is shut properly.

Then check for these other common issues:

  • Is the power supply on?

Check the dishwasher is switched on at the mains and that it hasn’t been unplugged.

  • Is the filter blocked?

Sometimes a dishwasher won’t start if there’s a blockage. Follow the instructions in the first section on how to unblock a dishwasher.

  • Has the fuse tripped?

Look in your manual for instructions on locating the fuse and determining whether it is functioning properly. If you do have a blown fuse, then call a professional to replace it.

What to check for when you’re dishes aren’t coming out clean

If your dishes are coming out of the dishwasher still dirty, there’s clearly a problem. But it may be one of a few different things. Here’s what you should check for:

  • Are you overloading your machine?

Check the dishwasher’s manual for instructions on its capacity. And read our guide on the best way to load your dishwasher.

  • Are you using the right detergent?

Make sure you’re using a good quality detergent, whether it be tablets or powder. Read our guide to find out which detergents are suitable for the dishwasher.

  • Do you scrape off food remains before loading dishes into the dishwasher?

It’s a good idea to scrape leftover food into your food waste bin before loading dishes into the dishwasher. (There’s no need to pre-rinse your dishes though, unless your dishwasher is very old, as it’s a big waste of water.)

  • Do you have hard water in your area?

If so you may need to use a special rinsing agent as hard water can leave a film on dishes after they’ve been cleaned.

  • Do you need to clean your dishwasher?

If your dishwasher is dirty, your dishes will come out dirty. Despite the fact dishwashers are designed to clean, they can still get dirty themselves, so it’s a good idea to give yours a regular once over. Read our guide to cleaning a dishwasher for all the tips and tricks you’ll need to get it sparkling again.

How to banish dishwasher smells

If you’re opening your dishwasher to be greeted by an unpleasant odour, the good news is that it should be easy to sort it out. Just follow our guide on how to stop a dishwasher smelling bad.

Originally published