What does a water filter do ? How does it work ? When you know the answers to these questions you can understand why more and more people are buying them. Filtering water has been a human habit for about 6000 years. First we filtered water through fibres to clear the cloudyness of muddy streams and we have evolved now to using advanced technology to rid ourselves of all sorts of microbes and other impurities.
These days our drinking water is treated so well that the bacteria it contains is minimal. There is however, a price to pay for this. The chemicals used to keep the water bug free can sometimes leave a taste very far removed from crystal clear water. This is why you see so many people wandering around with bottled water these days. 30 years ago people would have laughed at the idea of buying water in bottles until we started to realise what was in it!
Most water filters today use what is called activated charcoal. Activated charcoal is charcoal, which itself is mostly carbon, which has been through chemical processes to make it soak up more water. The water is absorbed into the charcoal which retains the impurities and pure water passes out the other end. Charcoal filters are just one kind of filter but they are not the be all and end all. Charcoal filters will absorb most of the impurities found in drinking water but they will not remove lead and copper.
Another type of filter is an osmosis unit, or rather a reverse osmosis unit. This involves a great deal of water being pushed, or pumped, through a very very fine membrane. It not only separates the bacteria etc but it separates some of the water too. This water is wasted so reverse osmosis filters are not the best option for any domestic situation. Another filter system is called ion exchange and involves a chemical process within the filter which exchanges filter ions with the natural ions in the water which contain minerals and salts. Removing, or neutralising these salts and minerals has the effect of softening the water and reduces the build up of scale. Ion exchange filters do not work however when there is a lot of iron in the water.
Choosing a filter then depends on the water you have. For best results telephone your water supplier and ask for the results of their latest analysis. This will give you a better idea of the best kind of filter for you.
Next is how you install it. All filters have a cartridge and most are charcoal. You can exchange your kitchen tap with a 3 way tap seen above left. This will give you hot and cold water as normal, then a third lever is connected to a water filter which is installed under the sink. See our project on changing taps to install the unit and use the manufacturers instructions to connect the filter.
A water filter can also be installed "stand alone". See the image top left for this kind. These very often mean drilling the sink unit to install and you can get instruction on how to do this, and fix the tap, from our project on instant boiling water taps. Click on the images to find out more about water filters and to buy them.