Ultraviolet water purifiers cleanse water by bombarding the water with UV-C rays that kill the microbes in the water. We think of filtering water to remove contaminants and odors and tastes but that’s not what ultraviolet machines do. What they actually do is sterilize the water rather than filter it. The UV-C rays alter the DNA of the microbes so that they cannot reproduce and they die. The types of microbial critters that UV lights sterilize are fungi, bacteria, viruses, and other nasties. Filtration devices, on the other hand, filter contaminants out of the water that are larger than the holes in the filter. They get trapped by the filter and therefore removed from the water. UV-C rays are also called “germicidal UV” for this reason.
Sterilizing and filtering are two different techniques for handling water contaminants. And because ultraviolet machines sterilize rather than remove contaminants, they are best combined with filtration systems that take contaminants such as trace metals out of the water. UV does not remove chemicals such as chlorine or trace metals such as calcium and magnesium from the water.
Ultraviolet water purifiers have lots of advantages over other ways of purifying water. Among the advantages are that they don’t introduce new chemicals into the water like whole house salt-based water softeners do. They also do not produce any organics or other byproducts. They don’t change the taste or pH or other properties of the water. They don’t harm water pipes and leave deposits or create problems for your septic field. They are also very easy to install and maintain which is not true of all water filtration devices.
Ultraviolet purifiers are best used in whole house applications since you really can’t put UV devices at individual faucets and sinks. Ultraviolet purifiers are also used in applications that wouldn’t readily come to mind such as in aquariums and ponds. Pond UV filters are used to clarify water (remove the green cast) and to remove the algae organisms.
Ultraviolet purifiers work by sending rays through a glass tube called a flow chamber to radiate the water. A little periodic maintenance is necessary to wipe off the glass tube to keep crud from building up and reducing the effectiveness of the UV-C rays. Light bulbs are very long-lived and easy to replace. UV-C rays are more intense than sunlight and operate at a light wave that the human eye perceives as purple which is how we get the “violet” in ultraviolet