Most water purification systems make use of filtration media to trap microorganisms such as bacteria, viruses, and cysts. The effectiveness of any of these filters will depend upon what sorts of media are being used, and the micro-pore size of the media. Charcoal, often activated coconut charcoal, filter membranes, and granulated metals will all be used to remove different pollutants from the water. While many water filters will have a very small pore size, such as 1 micron or less, others will have a pore size of up to 10 microns. A large pore size means that more pathogens will be able to enter the drinking water, and viruses are so small that unless the very finest filters are used, viruses will infest the water.

All of us are familiar with ultraviolet light – the sun delivers it to us every day. This sunlight is considered to be in 3 wavelengths: long-wave and medium-wave ultraviolet, which are what we perceive as visible light, and short-wave ultraviolet, which is generally used for ultraviolet water sterilizers.

Short-wave ultraviolet light does not occur on the planet’s surface since our atmosphere blocks these rays. It is, therefore, necessary to artificially produce short-wave ultraviolet, and this is generally done with the use of mercury vapor lamps. These are often called germicidal lamps and are made with a special clear quartz casing – glass will block most of the short-wave ultraviolet light.

When treating water with an ultraviolet water sterilizer, the water is bombarded with UV. Any bacteria, viruses, protozoa, or amoebae in the water are killed. Although highly effective at treating water contaminated with microbes, ultraviolet will do nothing to remove heavy metals or other inorganic pollutants from the water.

In order to obtain the maximum sterilizing power of ultraviolet light, it is necessary for the water that is being treated to be clear so that the light can effectively reach the pathogens. Water that contains silt or sediment or rust will interfere with the light’s sterilizing ability. To get the maximum benefit from a UV system, a pre-filter to remove particles and sediment is required.

For those on a municipal water system, ultraviolet water sterilization can help to assure that household drinking water is safe. Chlorine will kill bacteria, but is fairly useless against viruses and cysts. By installing an ultraviolet sterilizer, all potentially dangerous pathogens can be eliminate.

In most cases, it will only be necessary to replace the germicidal lamp once a year. Once installed, ultraviolet water sterilizers can be used for an entire house, or can be placed under a specific sink. Achieving close to 100% sterilization of viruses, bacteria, and cysts will lower the probability that you and your family will suffer from the illnesses caused by waterborne pathogens.