Do UV Light Water Sterilizers Work?

do uv sterlizers really work - boy drinking filtered water

Do Ultraviolet Water Purification Systems Really Work?

Yes, UV water purifiers are effective at removing microbiological contaminants in water such as bacteria, fungi, protozoans, viruses, and cysts. Ultraviolet (UV) Water Purification is a proven technology that uses UV light to destroy 99.99% of harmful microorganisms in water.

UV water sanitizers are a safe, chemical-free way to treat water. Today, UV water disinfection systems are used around the world in millions of businesses and homes.

UV disinfection is a proven technology that destroys 99.99% of harmful microbes in water

How Does UV Water Disinfection Work?

During the ultraviolet water treatment process, water passes through a UV water filter system and all living organisms in the water are exposed to a UV-C light which attacks the genetic code of the microorganism and rearranges the DNA making it so the microbe can no longer function and reproduce.

If a microorganism can no longer reproduce, it cannot replicate, therefore it cannot infect other organisms with which it has contact.

In simple terms, UV light filters treat water at the right light wavelength, thus destroying the DNA of bacteria, fungi, protozoans, viruses, cysts, and more (see list below). Learn more about the UV water filtration process.

Biological Contaminants Found in Water


E. coli


hepatitis A







typhoid Fever






How Long Does it Take UV Light to Destroy Bacteria?

The UV water purification process is quick! As water flows through the UV chamber, bacteria and other waterborne microbes are destroyed within ten seconds. The UV water disinfection process utilizes special UV-C lamps that emit UV light of a particular wavelength.

These UV waves (referred to as the germicidal spectrum or frequency) have the ability to disrupt the DNA of microorganisms. The frequency used in killing microorganisms is 254 nanometers (nm).

Why Use a UV Water Filter System?

The UV system will expose water to UV light and effectively destroy 99.99% of harmful microbiological contaminants in the water. If you purchase a system with an integrated prefilter, the filter will remove sediment, heavy metals, etc. from the water as these particulates can make it hard for the UV light to effectively sanitize the water.

In the UV water treatment process, water is fed through the UV system's chamber where light is exposed to the water. The UV light damages the microorganism's cellular function so that it is unable to grow or reproduce, and therefore dies.

As long as UV light is applied in the right dosage, UV treatment is effective against all bacteria (including Cryptosporidium and Giardia that have thick cell walls). UV light also works on viruses and protozoa. As a general rule, we recommend our customers install an integrated UV water filter WITH an RO drinking water system. This way, you get the best of all worlds! Microbiological contaminants are removed by the UV system and the reverse osmosis filtration system removes fluoride Fluoride (85-92%), Lead (95-98%), Chlorine (98%), Pesticides (up to 99%), and many other contaminants.

man drinking filtered water

Top-Selling UV Water Filter Systems

Viqua VIQUA VH410-F20 Model 18 GPM Combo UV System VH410-F20-
  • Economical UV Treatment

  • Lamp Life LED Display

  • 9 gpm UV for Small Home

Sold out
Viqua VIQUA D4 Model 12 GPM UV System - 650694-R 650694-R-
  • Color LCD Screen

  • Lamp Replacement Timer

  • 12 gpm Monitored UV
Sold out
  • Includes 5-Mic Pre-Filter

  • Lamp Life LED Display

  • 9 GPM Water Treatment

Sold out

Ultraviolet Technical Tips

How to Change a UV Lamp

Instructions on how to replace a UV water sterilizer lamp yourself, including step-by-step instructions and video.
Read More>

How to Clean a UV Sleeve

Cleaning the UV sleeve in an ultraviolet water sterilizer system is crucial to maintain optimal performance. Learn how to properly clean a UV sleeve.
Read More>

How to Maintain a UV System

Tips for proper maintenance of a UV water disinfection system. Find solutions, UV system troubleshooting tips and more.
Read More>

Explore Other System Types