Majjie's Blog

I've just been writing a glowing report on the new Grohe Blue Chilled and Sparkling Tap (see it in the Kitchen Design News Section). I saw it in a review of filter taps by the newly revamped Kitchen and Bathroom Designer Magazine, and was impressed. I was also recently sent an e-mail by a company promoting their own filter tap ... they seem to be the in thing for taps at the moment, especially if the water is either chilled, or boiling (or both) ... and I noticed an anomaly.

Designer Magazine stated that the "essential minerals remain" in water from filter taps ... and yet both the tap in the promotional e-mail and another of the taps in the magazine review, are using reverse osmosis ... which removes virtually all minerals from the water. (That's the danger of just using promotional material from manufacturers to provide technical information - there's a worrying shortage of truly independent product reviews in the kitchen industry).

On visiting a couple of the websites for these "pure water" taps I was quite shocked by the content. They both used fairly bogus pseudo-scientific blurb, to try and frighten you into buying one of their taps. They're implying (if not actually saying) that our tap water is dangerous and not fit to drink! One of them actually says that "calcium will cause degenerative diseases". That's really dangerous rubbish, especially in view of the prevalence of calcium deficiency in our society. 

I should perhaps say, at this point, that Grohe is definitely not one of these dodgy suppliers. They say on their website that their filters are improving on the "already high quality water from the tap". The filters used by Grohe taps are similar to those used by Franke, Blanco, Abode, Brita, Carron Phoenix, ISE, Zip Hydro and Quooker. They use physical filtration to remove particles and protozoan cysts from the water; activated carbon to remove chlorine and contaminants such as hydrogen sulphide, VOCs, pesticides and heavy metals; and they may or may not include a system such as ion exchange to remove carbonate (or temporary) hardness from the water and more efficiently remove heavy metals.

These standard water filters don't remove nitrates and other chemicals like fluorine. They may remove some calcium and some magnesium (as carbonates) but most of the magnesium and the more soluble calcium sulphate and calcium chloride remain in the water. They aren't guaranteed to remove bacteria either. In fact, a neglected filter may harbour growth of microoragnisms. It's always a good idea to flush the filter through with a few litres of cold water, if it hasn't been used for a day or two, and it has also been recommended that this sort of filter should be changed every six months, even if not heavily used. Be careful when buying replacement filters too. Don't buy cheaper unbranded refills for a boiling water tap, without checking that they can cope with the raised temperature.

So are these taps worth buying? Well, I'd say definitely yes - if you don't like the taste of your tap water. If you're quite happy to drink your tap water without treatment, then there probably isn't much point. Water UK suggests that you let your tap water stand for a while, if it tastes of chlorine; and that you chill it or add an ice cube, with perhaps a slice of fruit or a sprig of mint - to improve your tap water drinking experience (or more importantly perhaps that of your children or elderly relatives). They also point out that UK mains tap water is very high quality, some of the best in the world, and that in blind tasting tests very few people can detect the difference between tap and bottled water (if they are served in the same way).

The chlorine in tap water is, of course, there for a very important reason - it's to disinfect our supply and prevent the growth of microorganisms. It's the presence of chlorine that means it doesn't matter that the majority of water filters aren't guaranteed to remove bacteria. It's also the chlorine, though, that contributes perhaps the most to our dissatisfaction with the taste. Removing chlorine and the other contaminants mentioned above, including solid residues, just gives a quality of water that is much better for making tea and coffee and diluting squashes and cordials - as well as for drinking the water itself.

Whether or not it's worth buying a boiling water filter tap is a different question - but I've been a fan for years. Here's my first review of the Quooker - back in 2007 - and it's also worth checking out Franke's new Minerva 3-in-1 Kettle tap, which only filters the hot water, not the cold (and the hot water tank fits neatly under a kitchen unit, behind the plinth).

So what about the "pure water" taps? Is that just unnecessary overkill? Well, no - it's worse than that - because reverse osmosis generally wastes a lot of water. In general 2 or 3 litres are wasted for every litre of pure water produced. I don't think that can be justified in these times of increasing water shortage, when our tap water is of such high quality anyway. (The company that originally e-mailed me, about their new tap, never did reply to my question about the ratio of wasted water).

You'll also find a lot of discussion (Google's a wonderful thing) about pure water being bad for you ... which is also implied when Franke and indeed the Designer Magazine talk about "essential" minerals being retained. I'm not convinced by those arguments either. We get most of our minerals from our food, not the water we drink, and the other criticisms - that pure water becomes too acidic, or causes mineral and water imbalances in the body, are also a bit improbable. The gastric fluid in our stomachs is very strongly acidic and I can't see a bit of weak carbonic acid (a little carbon dioxide, from the air, dissolves in pure water) making much difference. 

It's true that drinking huge quantities of pure water in isolation, without any food, would be bad for you but that's also true of unpurified tap water. There have also been some epidemiological studies that show that hard water is much better for human health than soft water. Such studies are notoriously inaccurate, though, when it comes to establishing cause and effect and I don't think they necessarily mean that pure water is dangerous. My conclusion is that neither tap water, nor pure water, are health hazards.

If your tap water tastes bad and you don't drink much of it, then consider a water filter from any of the companies mentioned by name above. Drinking more water would be good for the health of most of us. If you come across a company that's trying to promote "pure water" and scare you off drinking your tap water, though ... I'd leave their products well alone.