I was talking about water filters the other day with a customer, and he asked me, “How exactly does a water filter work?” I’ve spent so much time doing this that I sometimes forget not everyone has the same background and experience with it that I do – and water filters are really interesting!
Activated Carbon – The Hero of the Filter
There’s more than one way to filter water, but the most popular in home applications is an activated carbon filter. These filters feature tiny particles of carbon or charcoal – usually from an organic source like coconut shells – that are porous and have a very high surface area, despite the small size. For instance, one gram of activated carbon has a surface area of over 500 square meters, which means that a very small amount of carbon can filter a very large quantity of water.
Adsorption – How the Carbon Cleans the Water
The highly porous material is important, because carbon filters the water through a process called adsorption. Basically, what happens is the water runs over and through the carbon particles, and the impurities and particulates in the water are picked up by the carbon and the water passes through clean.
What about Flow Rate?
Another consideration with a filter is flow rate. A higher flow rate, where water moves through more quickly, means that the water spends less time in the filter and there may be some minerals, chemicals, or other impurities that can get through. A lower flow rate means the water spends more time in the filter and is cleaner; this, of course, means that the filter may wear out more quickly and need to be replaced sooner.
How Often Should I Replace my Filter?
The impurities picked up by the filter are held on the surface of the carbon, which is why, over time, a filter stops being effective. You’ll notice a change in the taste and smell of the water coming out of the filter, and that means the time has come for a new one. Most filters are rated for about 300 gallons, which is usually about six months. If you use a lot of water, or if you have hard water or well water, the filter will need replacement more often.
If you have questions about water filters, or for help finding the right filter you can check out our fridge filter finder. We carry top brands and all fridge models including the ukf8001 filter, mwf, adq36006101, 4396508 and more.