/ Home & Energy

Do washing machines live longer with Calgon?

Washing machine with limescale

The heap of pointless products grows: we can’t find any persuasive proof that ‘washing machines live longer with Calgon’. Why are we sucked into buying products from manufacturers that won’t back up their claims?

Advertisers love exploiting fears. A key brand positioning tactic is to magnify a problem and then present your product as the solution. And that’s exactly what seems to be happening here.

The limescale science

Calgon claims that limescale makes washing machines break down and die early, and that its tablets make them ‘live longer’ by preventing this alleged cause of premature death. But this hinges on a shaky premise: does limescale really shorten the life of your washing machine?

After simulating three years of washing in hard water, but otherwise normal conditions of three loads a week at 40°C, we asked an expert with 17 years’ experience to inspect our washing machines for damage. Calgon kept the inner parts spotless, but the thin layer of limescale that had built up without it wasn’t enough to affect performance.

Our expert believes that it would take six to eight years of washing in particularly hard water before a machine would need attention for limescale build up. Plus, not even this would necessarily lead to the washing machine breaking down. And by this point you’d have spent £295 on Calgon tablets – enough to buy yourself a new machine.

Our ASA complaint

We’ve submitted a complaint to the Advertising Standards Authority (ASA) about Calgon’s claims, but there’s a wider issue. Why do we willingly accept the claims made by brands and manufacturers? And why do we think they’re doing us a favour by selling us their products?

Calgon may well have watertight evidence that one tablet per wash somehow extends the life of your machine. But no such evidence exists in the public domain, and the ‘research’ held by Calgon won’t be released to us for reasons of commercial sensitivity.

According to Calgon’s press office, the studies conducted were for internal use only – the results were never meant to be seen by current or potential customers. So how can Calgon possibly justify the claim that its product is solving a problem if it won’t prove that the problem exists? And with no evidence made available, why do we pay money for a product that can’t be justified to us by its own manufacturer?

eco-hopeful says:
28 May 2011

Instead of calgon I have a “magno” type ball in my washing machine. Bought it once and it should last 10 years for £15.00.
From a website:
“Magnoball’s magnetic power crystalises lime scale particles, these transformed particles are unable to settle in your clothes or on the heating elements of machines and pipes.
Economical and environmentally safe, once you start using the Magnoball you may no longer require anti-lime scale tablets to soften your water as the Magnoball will do this by up to 70%.”

Again, do I know if it works… you tell me!

Dislodge some limescale from the inside of your kettle and I think you will find that it does not stick to a magnet.

Maybe Which? should tell the Advertising Standards Authority about this dubious claim.


Look up Magnoballs on the Web and the general consensus is that they are a load of spheres. (says he trying not to be rude or activate the Which? profanity filter)

choo choo says:
28 May 2011

Calgon prays on people who are scared of being exposed to the large and unexpected cost of repair or replacing of your washing machine. It is really just a form of insurance, that covers the affect of limescale on the machine.

Based on the findings that Which? has made, Calgon has been using peoples fear of this cost to sell their product. This in itself is worrying.

However the most upsetting thing is that Calgon refuse to share their internal report on the effectiveness of their product.

If the results of their internal study are similar to the results of the research done by Which? then surely Calgon have been marketing, selling and profiting from a product that they knew has limited effect. ie they have been scamming the public to sell their product and make money?

It is well known that limescale can shorten the life of heating elements in washing machines, but that does not mean that every failure is caused by limescale. (The element in my kettle failed after less than two years despite the fact that I descaled it regularly.)

Old fashioned light bulbs provide a good example of poor understanding. We all know that bulbs usually blow when first switched on, so the logical conclusion is that they are best left switched on. A bulb in cupboard can usually be switched on and off many thousands of times without failure. Thus leaving bulbs switched on for longer than needed just wastes energy and costs money.

Buying Calgon and related products will not ensure that the heating element does not fail. In some circumstances (depending on the cause of hardness, temperature of washes and other factors), Calgon could be very beneficial but it’s probably not money well spent for most of us.

Maybe not on topic, but does anyone know about the ingredients of Calgon? It used to contain hexametaphosphate. Phosphates are well known pollutants and a lot of effort has been put into cutting down or eliminating them from cleaning products used in the home. A change in formulation of Calgon could be relevant to these discussions.

I discovered that a certain brand of kettle descaler seemed to be less efficient than it used to be. After searching for MSDS date sheets I discovered that the active ingredient had been changed.

Thanks very much Katie. You have confirmed my suspicion that the formulation of Calgon is very different from what it used to be. I assume that sodium citrate is there to decrease limescale formation and sodium polyacrylate will bind calcium and magnesium ions (present in hard water), which can interfere with the action of the washing powder/liquid.

The ingredients suggest to me that Calgon might be useful but most of the ingredients are cheap chemicals, so it is not clear why Calgon is so expensive. It must be to cost of including aqua in the product!

Citric acid, in a powder form, is available quite cheaply from the chemists and is very effective on limescale. Citric acid can also be found in lemons and lemon juice. Half a lemon pushed onto the spout of a tap, will soon get rid of the scale.

James Cole says:
28 May 2011

Every year or so, I would purchase a couple of single-use saches of de-scaler from a washing machine reair shop and put them in the dishwasher and washing machine. It would completely remove all limescale and save on repair bills. Now I have moved to a soft water area and after a few months, the limescale in the kettle finally vanished without de-scaling. Another bonus is that I use less washing detergent, soap, shampoo and no dishwasher salt at all. The thing that amazes me though, is the fact that local supermarkets still sell Calgon and dishwasher salt despite not having to use it in this area.

Doesn’t amaze me . . .

Last year I spent a lot of money on a large capacity washer drier and I wanted to know whether I should use Calgon or similar or whether it was just a pure con.

Now if Calgon offered to replace your machine if it broke and you had used their product then they may have a leg to stand on but they don’t and thus they don’t.

John Whitehead says:
28 May 2011

Does Calgon actually work as a water softener? Even if so, I never understood why it would extend a washer’s life, although I can understand that it would stop limescale build-up on heater elements. As a water softener, I viewed it primarily as a means of reducing the amount of washing powder needed, but since its cost is so high, that doesn’t make economic sense. So I found low cost alternatives from Wilco and, latterly, from Morrisons, so that I could economise on washing powder.

On the disconnected subject of light bulbs, my understanding is that the life of conventional filament bulbs is limited mainly by the number of hours switched on, rather than by the number of switchings, whereas the inherently very long life of low energy bulbs (being essentially gas discharge devices) is reduced by frequent switching (as is the case with fluorescent tubes). So, in my house, we have low energy bulbs in situations where the bulbs are left on for long periods and filament bulbs in situations where the bulbs are switched on for short durations only, and maybe subjected to frequent switching. The best solution is LED bulbs (if you can get them bright enough) since they are VERY low energy and are not troubled by frequent switching, as far as I know (but they are expensive to buy).

Alexander J Smith says:
28 May 2011

What about the washing machine manufacturers who recommend Calgon in their machines. Are they simply a part of dubious sales strategy? Surely they have tested the effects of Calgon over a period of time.

Yes after spending about £400 on a washer-dryer I got “sucked in” by the Calgon advert and use it every time but why is it so expensive?

I have obtained a current safety data sheet for Calgon, which lists the active ingredients. This is dated 2007. I believe that Calgon has greatly changed in composition at some time, probably to eliminate phosphates and make the product ‘greener’. Product reformulation is commonplace, otherwise and helps to keep Which? busy comparing new versions of household products.

unkybob says:
31 May 2011

we use soda cristals in our washer insted of calgon every time we do a wash on 60 it dose the same job and only costs around £2 per year from homebargins we use 1desert spoon in with the soap poweder it works best at higher teps thats the reason we only use it on a 60 wash

I’m really pleased that you have done this research! When I bought my first washing machine I did buy a water softening product to put in it (not Calgon because my husband didn’t like the smell of it!), but that Hotpoint machine broke down so many times that it didn’t even have the chance to build up limescale before I threw it away!
We haven’t bothered with Calgon with our washer dryer, we don’t wash many things at more than 40 degrees and I don’t expect limescale to be the thing that will lead to my machines death in the end.
Strangely we do seem to get a build up of scale in the powder drawer which is unsightly and needs to be chipped off every once in a while. I’m not sure if it is a mixture of undissolved powder and softener but it is a complete pain to remove!

Hi Victoria.

I think that you will find the build up in the powder drawer is caused by modern machines’ useless insistence on filling with only cold water.

Like Calgon’s claims, the current clams that cold fill only is more environmentally friendly are fundamentally flawed and are being exposed to more and more question. (Indeed in many countries, such as Germany, Australia and the USA, there is no such thing as a cold fill machine on the market but there is greater environmentally friendliness. In Germany it’s actually against the building regulations to have a house which does NOT have hot supplies to all dishwashers and washing machines now.)

What is less well publicised, but also less in doubt, is that cold fill only and cooler wash cycles undoubtedly DO cause deposits and build ups of various sorts of slime, mould, scale (but not limescale) and bacteria within your machine, which is why many manufacturers (often in very small print) recommend a boil wash with no laundry in once a month to help remove these nasties.

I’m drifting off topic, but if you were to research this on the Web you’d quickly find that any possible savings in fuel consumption are pretty much outweighed by the increase in spend and environmental damage caused by more frequent repairs and replacements.

sam says:
4 June 2011

We live in very hard water area but instead of spending a fortune on Calgon, descalers and various bathroom scum removers, we had a water softener installed about 10 years ago. This has made a huge difference to the amount of cleaning I have to do and has reduced the number of repairs/replacements to kitchen appliances we have had. It also means that we only have to use half the amount of detergents.
Someone estimated that the cost of Calgon was about £600, so perhaps it would be better to invest this upfront in a water softener instead. Obviously some work better than others. Maybe Which? could run some tests on these.

I wrote an article about this very subject in 2003 ( http://www.washerhelp.co.uk/limescale_2.html#cl_q1 ) and I’m glad to see Which? looking into it. Some of the points I raised were that people who have no hard water were still heavily targeted. As a washing mahcine engineer I’ve often shouted furiously at the Calgon adverts on TV.

The tool on their web site to advise you if you needed to use Calgon or not was faulty for years despite my reporting it to them and getting replies. Between 2003 and 2009 it advised me that my water was hard in two different houses in different towns when my water authority confirmed it wasn’t, and I knew that no one in these (big) areas had limescale problems.

Also, detergent manufacturers and washing machine manufacturers advise that if you do not use the correct dose of washing machine detergent you can experience limescale problems. This statement surely also means that if you do use the correct amount of detergent you will not suffer limescale problems? All washing machine detergents have ingredients and water softeners to protect washing machines from limescale, so no extra product should be required.

What Calgon appear to do is strongly imply to all that without Calgon you will not be protected, and that it contains properties that protect against limescale when the truth is that washing machine detergent should do the same job as long as you use the appropriate amount. To be fair, using Calgon will allow you to reduce the amount of detergent required to the levels advised for soft water. Therefore it’s real use is to save on the amount of detergent you use.

I never did the research that would tell me if the cost of Calgon plus the reduced amount of detergent would be significantly less than just using the right amount of detergent in the first place or not. My gut feeling is that it wouldn’t because this is not how Calgon is promoted. It’s only promoted with scare tactics implying you must use it or your washing machine will suffer serious problems and not last very long. It would be great if someone like Which? could work out if it is viable to use as a method of reducing detergent usage – it’s possible it is – I don’t know.

The waters are somewhat muddied by the small list of washing machine manufacturers that endorse Calgon. This would seem to fly in the face of their advice that if you use the correct dosage of detergent you should not suffer from limescale issues. My personal suspicion is that they may simply endorse it because it helps insure against the countless numbers of people who probably don’t use the right amount of detergent, suffer from limescale issues – and blame the washing machine for not lasting very long. Either that or it’s simply a financial consideration that persuades then to endorse it.

A tablespoon of soda crystals does the same job as Calgon for a fraction of the price – and soda crystals help shift stains like grease; you only need more than a tablespoon if you have heavy staining or lots of grease. You will find packets of soda crystals hidden amongst the packs of detergent in supermarkets. You can still use about 1/3 less detergent with soda crystals to avoid unwanted excess foam.

If you want your washing machine to last longer, avoid bad smells and not have to perform regular “maintenance” washes, then wash at 60C as much as possible. The slight increase in running costs still works out cheaper than repairs or buying a new washing machine, especially if that means taking time off work for delivery and installation.

Conclusion: you don’t need Calgon and it’s too expensive for what it is!

geoff clement says:
4 April 2012

Thanks for all the information regarding softening of water. My wife does indeed suffer from the problem of black slime building up on our LG washing machine door seals. I tend to agree with people that say this is because of using 40oC as the wash temperature. Since I am working out of the country at present on a desalination project on the island of Aruba we should take a leaf out of their book. They have one of the purest waters I have ever experienced in a public network and neither do they use chlorine to disinfect the water. They use ultra-violet light. There are literally no lime scale problems here even though the produced water is re-mineralized. I am of the opinion that limescale formation in washing machines is exaggerated. The reason I say this is that the machine heating element initially switches on to heat the water then modulates to keep it up to the required temperature. The element reaches the same surface temperature each time it switches on. It is this high element surface temperature that causes the formation of scale on the element. There is nothing you can do about this. You only have to look at the way a kettle boils to see the bubble formation at the element surface to see that the element is no longer fully immersed in water. It is obvious that this is evaporating the water to dryness at the element surface thus forming scale. Hard water areas do it quicker! I will be recommending to my wife that a 90oC wash weekly will inhibit the formation of slime and bacteria. I live in a soft water area but suffer from black slime formation in the cold water system of my house. This is despite the water company having installed a 5 micron filter in the supply line to my house. In my experience some types of bacteria are known as slime forming bacteria. They can be a plague on the industry that I work in and it seems as if they are making their presence known in washing machines!
I apologize for being so long winded,

A 5 micron filter is not much use for removing bacteria because most individual bacteria are smaller than this. The filter will only remove clumps and chains of bacteria. To remove bacteria a pore size of 0.5 micron (micrometer) or smaller is needed.

Oops – the spelling checker has put in a US spelling – micrometers instead of micrometres.

Replying to Geoff’s post…

For “heavy duty” cleaning of the gunk and slime in the washing machine, I suggest buying the “affresh” tablets online. These are very good and really do shift the nasty stuff hidden inside the washing machine. I suggest using them every 6 months. You don’t need to use them weekly.

Before you use affresh, be sure to clean out the soap drawer and its surrounding, and then clean the machine’s filter. After using, make sure affresh is thoroughly rinsed out.

Hope that helps.
As for Calgon, I’ve never used it and I’ve not had a problem with limescale damage to the washing machine, which proves my addition of soda crystals to every wash is doing the same job as Calgon – but soda crystals are much cheaper. Don’t use it on small loads as you will get too much foam, because modern washing detergent foams too much.

Our 5 year old Zanussi just died. Contrary to what others have said on here, all parts inside the machine were extremely encrusted with limescale, like thick concrete. All the hoses inside were almost completely blocked and all the working parts (pumps etc) were being jammed by lumps of gravel. We do live in a very hard water area and as we have 3 young kids our machine is used daily, often more than once! So in 5 years we’ve probably used our machine the equivalent of 10-15 years for an average machine.
However, I have a strong suspicion that most of this scaling has happened in the last 2 years.
We used to have a Siliphos dispenser to prevent scale build up. For those who don’t know what this is, it’s a box of glass-like balls which the cold water supply goes through. You just need to top up the balls every few months.
When we had a new bathroom installed a couple of years ago, on the advice of the plumber this was changed to a lifetime magnetic descaler.
Now, this may well stop scale depositing in the plumbing, but all that limescale now seems to end up in appliances. Certainly our kettle furs up much much quicker than it used to.
My concern is, how do I stop our brand new machine being killed off by this excessive limescale deposit in 2-3 years? If calgon (or similar) is useless, what can I use? I’ve heard of magnetic balls you can put in with your washing, but won’t that just be replicating what the descaler we already have does?
Any advice would be appreciated!

I don’t think anyone is saying Calgon is useless, just that it’s commonly unnecessary and aggressively marketed to scare people into using it. The Which? tests showed that Calgon kept the parts inside the washing machine “spotless”, but that the machines they tested along side without using Calgon only had a very thin layer of limescale which wouldn’t have affected the machine. The implication there is that as I’ve always said, even in hard water areas if you use the correct amount of detergent the machine should be protected.

According to washing machine manufacturers, limescale builds up in washing machines if the correct dose of quality detergent isn’t used. Therefore there’s the possibility you need to use higher doses of detergent in your machine. Alternatively yu sound like the kind of example where using Calgon may well make sense.


The hardness of water can change with time. I used to have very hard water until the company increased the amount of river water in the supply. At one time it changed from day to day, which was obvious when taking a shower. My water has become softer and yours has become harder.

I would not waste your money on magnetic descalers, which don’t work. These and other descalers often claim to save electricity too, which is obviously nonsense.

You may have less limescale problems if you wash at lower temperatures, but it is important to do a wash at 60C periodically, maybe once a week, to avoid growth of bacteria and nasty smells.

@tombooth The correct dose of detergent is usually enough to prevent limescale in the main washes. If you also add a tablespoon of soda crystals to every load it will ensure the water is always soft. Use about 4 times more soda crystals if you are washing very greasy items or items containing remains of baby oil.

All water softeners, like Calgon, are useless during the rinse cycles because most of the stuff gets rinsed away and extra rinses remove it better – great if you have sensitive skin. Limescale can form even from cold water, because toilet pans get scaled up and need regular use of a strong limescale remover designed for toilet bowls.

Given how often your machine gets used, you could consider using a limescale remover designed for washing machines once every few months, using it without any clothes in the drum.

The build up of limescale in a toilet bowl is the result of a reaction between urine and hard water. Which is why some commercial premises use waterless urinals, which don’t suffer from this problem.

@Mike I never knew that. I get limescale everywhere water touches and cleaning the bathroom requires the use of a limescale remover to get rid of the scale. It’s such a nuisance, but I’ve not seen white bits in the washing machine drum or on the door seals. I’m sure soda crystals are preventing hard water deposits in the washing machine.

Aimee says:
16 June 2012

My grandma’s washing didn’t live longer with Calgon – she tried it and she had to get a washing machine. Mine has not used Calgon yet – and we won’t – and we’ve had it for a while.