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How eco-friendly are your dishwasher tablets?

From packaging to biodegradability, here's what to look out for when shopping for more sustainable dishwasher detergent 

If you've got a dishwasher, then loading it up and popping in a dishwasher tablet may well be such a familiar part of your daily routine that you do it on autopilot. But it's important to be aware of the pollution that dishwasher tablets can produce.

We've just tested 12 dishwasher tablets on their cleaning ability and eco credentials, including big brands such as Fairy, budget supermarkets like Aldi and Wilko, and those making green claims, for example Ocean Saver, Smol and Splosh. 

Some of these brands make impressive-sounding claims to be better for the environment, but our tests cut through the marketing speak to tell you which are truly worth your money.

Find out what to consider when shopping for dishwasher tablets so that you can minimise your environmental impact. 

Want to know how your usual dishwasher tablet compares to the others on test when it comes to sustainability? Head straight to our dishwasher tablet reviews to find out.

Is dishwasher tablet packaging recyclable? 

Our tests found that it's a mixed bag. But ideally your dishwasher tablets should come in refillable packaging, or packaging made from recyclable materials, with the recycling symbol clearly displayed and information on how and where you should recycle it – whether at home or a large supermarket, for example. 

Some give no recycling guidance at all, not even revealing the packaging material, which might have helped you work it out for yourself. 

The worst one we tested displayed no recycling information at all, and its dishwasher tablets were individually encased in non-recyclable wrappers that needed to be removed before use. 

Even some of those that generally impressed us could have been improved in small ways. 

For example, one comes in a refillable box with no recycling information. So, when you do eventually need to get rid of the box it's not clear how you should do so, but that shouldn't be for a long time if you're happy to stick with the brand.

We also checked whether any came in packaging made from recycled materials, but none of them were. 

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Do eco-friendly dishwasher tablets clean well?

Clean, shiny cutlery

We had hoped to award our Eco Buy logo to some of the dishwasher tablets we tested. But most of the tablets we tested scored disappointingly for our sustainability assessment. The few that earned more than three out of five stars for environmental impact don't actually clean that well. 

And, while you might be prepared to put up with less than perfect cleaning for a good cause, you're not actually helping the planet if you need to wash things twice, using more detergent, water and energy in the process. 

Nor if you leave half a box of detergent languishing at the back of your cupboard because you abandon it for another brand. A dishwasher tablet must clean well as a basic minimum. 

Are dishwasher tablets harmful to the environment?

There are several strands to this, including whether the dishwasher tablets contain anything harmful to the environment in the short or long term. 

Also whether ingredients are biodegradable (can be decomposed naturally by bacteria or other organisms without hurting the environment) and whether any ingredients are classed as PBT – persistent (resist environmental degrading), bioaccumulative (build up and become more concentrated as they go higher up the food chain) or toxic. 

We were disappointed to find one that is advertised as being environmentally friendly but it contains ingredients that:

  • Have poor biodegradability.
  • Have adverse and long-term effects on aquatic organisms.
  • Are toxic to the environment.
Couple loading a dishwasher

Luckily, some don't contain any chemicals of concern. We've summarised our findings in our dishwasher tablet reviews so you can check these to pick one that combines reasonable cleaning performance with ingredients that cause less pollution. 

Find out how to buy water friendly cleaning products and toiletries

How transparent are dishwasher tablet brands about the ingredients they use?

Worryingly, not all dishwasher detergent manufacturers are equally open about the impact of the ingredients they use. 

We were only able to gather as much data as we did because we specifically asked the manufacturers. And, even then, many of the manufacturers didn't provide all of the information we asked for. 

Some contain environmentally unfriendly substances but didn't display an environmental hazard statement on their label. We believe manufacturers should be transparent with consumers so that we all have the option to make environmentally conscious decisions. 

Reduce your environmental impact when using a dishwasher

Well-organised dishwasher

Although not an exhaustive list, here are some other tips for using your dishwasher sustainably:

  1. Choose an eco-friendly dishwasher next time yours needs replacing. Any dishwasher with an Eco Buy badge will be energy efficient, water efficient and – crucially – excel in both performance and reliability. A dishwasher that works well, and isn't likely to break down quickly, won't need replacing as quickly as a dishwasher that cleans halfheartedly and/or malfunctions. Find out more about the most energy-efficient dishwashers and Which? Eco Buys
  2. Scrape food residue into the bin once you've finished eating (bonus points if your council has food bins). Your dishwasher will need to work harder if it has to tackle crusty dishes. There's no need to pre-rinse them manually, though, as most dishwashers have a pre-rinse function.
  3. Only run your dishwasher for a full load. Don't run it repeatedly for small loads, or you'll be wasting water and energy, even if you've got an Eco Buy. The same applies to washing machines.
  4. Maintain your dishwasher to prolong its life and get more out of each clean. That includes cleaning it, descaling it and unclogging the filter when needed.
  5. Load your dishwasher properly. A well-organised load will get a more thorough clean, as the water will be able to get everywhere it needs to. Saving you from needing to wash anything twice. If you're prone to sticking things into your dishwasher willy nilly, watch our video to find out how to load your dishwasher properly

Homemade natural dishwasher detergents

We don't recommend concocting your own dishwasher detergent, even though there are plenty of lifestyle blogs telling you how to do so. 

You don't want to risk ingesting anything unsafe, and if it can't clean as effectively as a branded product it will be less hygienic. 

In addition, you won't be able to predict the impact on your dishwasher, which you don't want to risk ruining. 

Vinegar is a cheap cleaning product and you probably already have it in your cupboard. But don't use it to clean your dishwasher. Discover the eight things you shouldn't clean with vinegar

Which? dishwasher tablet tests

Inserting a dishwasher tablet into a dishwasher

We tested 12 dishwasher tablets in our latest batch. Find out which ones impressed us with their cleaning ability and eco-friendliness by heading over to our dishwasher tablet reviews.

Detergent manufacturers reformulate periodically, so we retest their products to bring you the latest results. 

If you checked our reviews a few months ago, you might be surprised to see newer versions of the 'same' products scoring higher or lower than before, depending on how their new formulation compares to their last one. 

Find out more in our guide to how we test dishwasher tablets.