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Plumbing

Find guidance on leaks, pipework, drainage, water pressure and everyday home plumbing issues.

Plumbing

Home Repairs: Blocked Dishwasher

If you notice that your dishwasher is slow to drain or – even worse – completely blocked, the first instinct may be to call your local plumber or chase the dishwasher warranty. While your plumber will definitely be able to help with the problem, you may be able to do the job yourself.

If you notice that your dishwasher is slow to drain or – even worse – completely blocked, the first instinct may be to call your local plumber or chase the dishwasher warranty. While your plumber will definitely be able to help with the problem, you may be able to do the job yourself.

Dishwashers are one of the many unsung heroes in the home; it is only when they are not fully functioning that you realise how much work they save (and how many family conflicts they prevent). Even if you rinse items before placing them in the dishwasher, debris will gather over time and will, eventually, form a blockage. We are going to cover the basics.

How do you know if you need to unclog your dishwasher?

There are five signs that your dishwasher would benefit from (or desperately needs) to be unclogged:

  1. Water from the dishwasher is backing up into the kitchen sink;
  2. The dishwasher drains slowly at the end of the cycle;
  3. Your dishes and cutlery are coming out of the dishwasher dirty;
  4. Your dishwasher is noisier than usual;
  5. You have standing water at the bottom of the dishwasher after a full cycle.

To unclog your dishwasher you will need:

  • A cup or jug to empty it out;
  • A toothbrush to clean the filter;
  • A towel/cloths
  • Vinegar and bicarbonate of soda or baking powder;
  • Rubber gloves (optional).

Step one:

First of all, you need to remove the filter, cutlery holder, and racks from the dishwasher. Once this us done, bail out your dishwasher as best you can. Add one cup of water mixed with one cup of vinegar and allow to stand for 30 minutes.

Step two:

With your rubber gloves on, use your jug or cup to remove any standing water. Use your hands to remove any food or debris, and give the filter a good clean.

Step three:

Replace your cup rack and place an upright cup filled with vinegar on it. Run a hot cycle. Once this ends, sprinkle a cup of bicarbonate of soda and another cup of vinegar on the bottom of the dishwasher. Leave for half an hour before running another cycle.

The vinegar and baking powder/bicarbonate of soda trick is often as effective as expensive dishwasher unblockers. If it doesn’t work, you may need to contact a local plumber to take a look for you.

As always, prevention is better than cure. Just as you should clean your washing machine regularly, your dishwasher will run better if it is cleaned. Run a cycle of vinegar and bicarb every few weeks to prevent blockages and keep your dishwasher functioning well.

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Looking for more plumbing advice?

Find clear, practical answers to common plumbing questions, helping homeowners understand everyday issues, know what checks they can carry out safely, and when it is best to contact a qualified professional.

  • What should I do if I have a blocked drain or sink?

    Start with a plunger - create a good seal and use firm, steady pressure. For a kitchen sink blocked with grease, bicarbonate of soda followed by vinegar can help. If that's not shifting it, a drain snake reaches further down the pipe. Go easy on chemical drain cleaners as they can damage older pipes and rarely sort the root cause. If the blockage keeps coming back, affects more than one outlet, or you're getting unpleasant smells, call a plumber rather than trying to patch up the problem.

  • How can I tell if I have a hidden water leak?

    The most obvious clue is a water bill that's gone up without any change in your usage. Beyond that, listen out for running water when everything's turned off, and watch for damp patches on walls or ceilings nowhere near an obvious water source. A quick self-test is to turn everything off and watch your water meter - if it's still moving, there's a leak somewhere. Tracking down exactly where it is usually needs a specialist detection kit, which a plumber can bring in without having to rip everything up.

  • What should I do if I have a burst pipe?

    Turn off your stopcock straight away - you'll usually find it under the kitchen sink or where the mains water enters the property. Once it's off, open your taps to drain what's left in the system, switch off the boiler if you can do so safely, and mop up any standing water before it reaches electrics or flooring. Then call a plumber. With burst pipes, the faster you act, the less damage you'll be faced with.

  • What is a gas safety certificate and do I need one?

    A Gas Safety Record is issued by a Gas Safe registered engineer after checking that all your gas appliances, flues, and pipework are safe. Landlords in England, Scotland, and Wales are legally required to get one every year and give tenants a copy within 28 days. For homeowners it's not a legal requirement, but getting a check done alongside your annual boiler service is a smart idea, particularly in older properties. Only a Gas Safe registered engineer can carry out the work or issue the certificate - you can check anyone's registration on the Gas Safe Register website.

  • Why is my water pressure low and can a plumber fix it?

    Low pressure usually comes down to one of a handful of things: a stop valve that's not fully open, limescale build-up in older pipes, a failing pressure-reducing valve, or an issue with your water provider's mains supply. In most cases a plumber can sort it - though if the problem is with the mains itself, you'll need to contact your water company first. Either way, don't just live with it - ongoing low pressure can sometimes point to something more serious.

  • How do I know if my boiler needs replacing or just repairing?

    If it's under ten years old and it's one specific fault, a repair usually makes sense. If it's over fifteen, has needed multiple fixes recently, is making strange noises, or your energy bills have crept up for no obvious reason - replacement is probably the better investment. A useful rule of thumb: if the repair would cost more than half the price of a new boiler, it's probably time to replace it.

  • How often should I get my plumbing inspected?

    There's no legal requirement for homeowners, but every two to three years is a sensible habit - especially in older properties or hard water areas where limescale builds up over time. Your annual boiler service covers some of the associated pipework too. And if anything seems off between inspections - odd noises, discoloured water, unexplained damp - don't wait. Get it looked at sooner.

  • Why do my pipes make a banging or knocking noise?

    That banging sound (sometimes called water hammer) usually happens when water flow is suddenly stopped or redirected, sending a pressure wave through the pipes. It's most common after flushing the toilet, shutting a tap sharply, or when a washing machine valve closes. Pipes that aren't properly secured can also knock against walls or joists. It sounds alarming but it's often an easy fix - a plumber can figure out whether it's a pressure issue, a faulty valve, or just some loose pipework.

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