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Ultraviolet (UV)

Ultraviolet (UV) in Water Filtration

Ultraviolet lamps used for water treatment generate UVC light, which has a germicidal effect at a much higher intensity than sunlight. Almost all UV lamps produce light with a wavelength centered around 254 nanometers, which is most effective at killing bacteria. Most water purification systems that use UV lamps work as part of a larger system of different filters.

UV light only kills bacteria, viruses, mold, algae, fungi and cysts such as Giardia or Cryptosporidium. UV lights have no effect on chlorine, heavy metals, volatile organic compounds or other chemical contaminants. However, it is the most cost-effective solution for residents who want to eliminate many biological contaminants from their water source. Research and testing show that UV light can also be effective in destroying some volatile organic compounds.

Water treatment using UV lamps provides a number of other advantages over other methods of destroying biological contaminants. The most important of these is that it does not introduce new chemicals into the water, does not leave intermediates and does not affect the taste, acidity (pH) or other properties of the water. Moreover, in addition to producing safe drinking water, it does not adversely affect either the plumbing or the wastewater system. The UV filter is relatively inexpensive and simple to install and operate.

How Does It Work?

Water purification is accomplished using a UV light source (lamp) that is enclosed in a protective housing (usually quartz). The lamp is mounted so that the flowing water is exposed to the UVC rays. The nucleic acid in the microbial cells absorbs radiation, which subsequently destroys the DNA structure of these organisms. The cell is thus sterilized and can no longer reproduce. It is considered dead and no longer a threat.


Ultraviolet treatment is a great solution for eliminating biological contamination in the tap water that we consume. Whether you use municipal water or have your own water source such as a well or lake the purpose of UV filters is solely to kill harmful biological contaminants. This UV filter should always be used in conjunction with other filtration methods such as activated carbon and reverse osmosis, which will remove the remaining contaminants from the water.

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