5 common contaminants destroyed by UV purification

(By Brian Campbell)

A method known as UV purification has become an increasingly popular means of purifying water and making it safe to drink. Most people associate UV rays with the sun, but as a water treatment technique, ultraviolet light can act as a highly capable disinfectant.

UV disinfection works by altering the DNA in microorganisms, making them unable to reproduce. This type of water treatment doesn’t actually filter the microorganisms out of the water; rather, it inactivates them and makes them unable to cause harm. The effectiveness of UV purification depends on the intensity of the UV light, the quality of the water source, and the length of contact time that water has with the UV rays.

Read on to learn about the 5 most common contaminants that are destroyed by UV purification. 


According to a report by the EPA, there are 6 types of bacteria that are potentially present in untreated domestic wastewater, including salmonella, shigella and vibrio cholerae. These bacteria can cause diseases such as gastroenteritis, typhoid fever, salmonellosis and cholera. 

Like all the contaminants on this list, bacteria should be removed from city water at a treatment facility before the water is sent to your home. It’s much more likely that you’ll have bacteria in your water if you have a private well source - but that’s not to say that city water is entirely bacteria-free.  


There are 4 classes of viruses that can be found in domestic wastewater sources: rotavirus, hepatitis A, norwalk agent and enteroviruses, of which there are 72 types, including polio and coxsackie viruses. Viruses usually cause gastroenteritis, but some enteroviruses can cause meningitis and heart anomalies, and hepatitis A can cause infectious hepatitis. 

It’s uncommon for viruses to be found in drinking water sources in the US, but again, viruses may leach into well water and even city water on occasions. 

Related: Can UVC Light Kill Coronavirus?


Protozoa may be found in domestic wastewater sources in four different forms, including giardia lamblia and cryptosporidium parvum. These microorganisms can result in lesser-known diseases such as cryptosporidiosis and giardiasis. 

Protozoa are largely found in swamps, soils, streams and ponds. Though municipal water is treated to remove protozoa prior to drinking, there may still be trace amounts of these pathogens in our drinking water. 


Cysts are protozoa at a stage where the protozoa have a thickened wall and protective membrane. Because of their different makeup, not all water treatment methods can remove both protozoa and cysts, which is why they’re often mentioned as separate contaminants. 

Giardia and Cryptosporidium are the two most common cysts you’re likely to find in water. They may be introduced into a water supply by a diseased animal or human. Cysts can make you sick, but generally don’t have long-term effects. 

Mold Spores

Just because you can’t see mold spores in water doesn’t mean they’re not there. Mold spores are tiny, and can grow inside the water pipes in your home. Normally, pipes don’t have the oxygen required for mold to grow, but if mold does have access to some form of food and oxygen, it may start to infest your entire water system. 

Mold can cause allergy-like symptoms such as coughing, sneezing, itchy eyes and red skin. It can occasionally cause more intense reactions. Water softeners and filters are most likely to be affected by mold growth, so placing a UV system before these units will better protect them.


So, why UV purification? It’s generally considered the preferred purification technique because it eliminates the need for chemical treatment, such as the use of chlorine, which may be harmful to health even in trace amounts. 

UV purification is simple and effective - it’s capable of inactivating viruses, cysts, mold spores, bacteria and protozoa. Just make sure you use the right dosage - a low dosage of UV may not completely inactivate all pathogens in water, especially if the water has a particularly high contaminant content. 

UV disinfection is also a versatile water treatment method, and can be either permanently installed in one location or used as an on-the-go water treatment, such as a portable UV water bottle. If you want to guarantee that your water is 100% safe for drinking, no matter what the source, UV disinfection should give you the reassurance you’re after. 

If you’re looking to buy a UV purification system for personal or whole-home use, it’s a good idea to test your water and determine which pathogens you need to remove, and to what level. Take note of the intensity of a UV system’s purification capabilities and check that the system meets your requirements. You need to be sure that a system is capable of making your water entirely safe to drink before you spend your money on it. 

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