UV Water Purifier Diagram

How Does a UV Water Purifier Work?

In the year 2020, purifying things is part of our everyday life. We want to purify the air we breathe, the surfaces we touch, the food we eat, and the water we drink. When it comes to killing germs, there’s no older method than using the power of the sun, or UV light.

UV light has been around since the beginning of time. The sun itself is a gigantic ball of UV light-producing atoms that expels huge amounts of radiation in all directions 24/7. This UV light radiation is what causes sunburn when you stay out in the summer heat for too long without sunscreen. It’s also what they use to bleach our teeth when they get too yellow. UV light can be helpful or harmful depending on the situation.

One of the most innovative uses of UV light radiation is water purification for homes and businesses. Special water systems have been designed to decontaminate the water of living organisms that may cost negative health effects on those that drink it or are exposed to it in other ways.

UV light can be used to decontaminate other things as well such as your cell phone. Common sense tells us that our phone is the dirtiest thing we own. We touch it more than anything else each and every day and in between texts and Youtube videos, we touch all sorts of things collecting germs and congregating them on our phones. UV light devices have started popping up that allow you to place your phone inside and blast it with high-intensity UV light to kill all the germs on it. But, I digress. Let’s talk about what a UV light water purifier is and how it works.

How Does a UV Light Water Purification System Work?

The bottom line is that UV light is extremely tough on DNA. That is why doctors always warn about skin cancer for those who are exposed to a lot of direct sunlight. UV radiation damages the DNA in skin cells and can lead to cancer. It’s the same principle at work when purifying water. The UV light disrupts the DNA by destroying the nucleic acids and puts a serious damper on cellular functions which ultimately leads to the germs dying.

A UV water purifier exposes germicidal ultraviolet wavelengths to live organisms such as bacteria, viruses, or cysts. UV radiation at a wavelength of 254 nm breaks the DNA of harmful microbes, rendering them incapable of reproduction. The UV light sterilizes drinking water and stops bacteria from transmitting disease.

What Sort of Microorganisms does UV Light Kill?

Pretty much any microorganism will be severely weakened and/or killed by UV light at least to the point where it won’t be able to cause you to get sick if you ingest it. Some common illnesses that can be avoided by using a UV water purification system are:

  • Meningitis
  • Cysts
  • Polio
  • Typhoid Fever Cholera
  • Algae
  • Fungi
  • The Common Cold
  • Coliform
  • Flu Virus
  • Giardia
  • Dysentery Bacilli
  • Cryptosporidium
  • Salmonella
  • E. Coli
  • Hepatitis B
  • Coronavirus

What is Inside a UV Water Purifier?

There are 9 main parts of a UV water purification system. It’s a really simple system that pumps water past a UV light and out the other side. By the time the water leaves the light tube, any microorganisms inside of it are now dead or weakened and the water is safe to drink. I’m going to go through each of the nine parts one by one and explain what it is. By the time you finish this section, you will have a solid understanding of what the components are and how they work together.

UV Ballast / Control Unit

Every light has a ballast. A ballast is a device used with an electric discharge lamp to obtain the necessary circuit conditions (voltage, current, and waveform) for starting and operation. All fluorescent and HID light sources require a ballast for proper operation. Dimming ballasts are special ballasts that, when used together with a dimmer, will vary the light output of a lamp. – Regency Lighting

The ballast is responsible for getting the correct amount of power to the light for proper function.


The inlet is a fancy term for “where the water comes in”. Typically water will be pumped or forced into the system with pressure. The inlet will have a valve of some sort to allow the operator to open or close the flow of water.

UV Chamber

The UV Chamber is where the magic happens. The water is pushed through a pipe. In the middle of the pipe is the UV light bulb which blasts the water with UV light killing all the bacteria and viruses in it.

Quartz Sleeve (For UV Light Bulb)

The UV light bulb is usually fluorescent and requires protection from water. Normally you would put some sort of glass around it to protect it, but regular glass actually filters out too much of the UV radiation (light) to be effective at killing the bacteria and viruses. Instead of glass, manufacturers have figured out they can use quartz. Quartz is a very strong crystal that is commonly found in nature and closely resembles glass. The UV light bulb is surrounded by quartz providing a protective layer and allowing enough of the UV light rays to get to the water to disinfect it.

UV Sensor

The higher-end UV purification systems will have a sensor that monitors the level of UV radiation being exposed to the water. If the levels drop below a threshold an alarm will sound and/or the system will shut down. For systems that are critical like those found in municipal water treatment centers, these sensors are key in making sure the water is being treated correctly.

Solenoid Valve

A solenoid is another word for a switch. Basically, if one of the sensors detects the UV light isn’t working properly, a switch will be triggered that shuts down the system. In the case of a Solenoid valve, the valve will be switched closed to stop the flow of the water.

Flow Meter

A flow meter is a high-tech sensor that detects the amount of water flowing through the system. Especially for larger systems, it’s important to constantly monitor the flow of water to make sure the entire system is operating and the correct capacity and at the right speed.

Are UV Purifiers Safe to Use?

UV water treatment is a completely safe process. It is free of dangerous chemicals and does not affect the chemical composition of water. A UV sterilizer disinfects with the use of UV-C light. UV-C light is toxic to people in the same way as it is toxic to microscopic living organisms. However, unless you touch or stare directly at the UV bulb while it is on, you are not at risk of exposure.

Are UV Purifiers Effective?

UV sterilizes water efficiently and effectively. UV disinfection kills 99.99% of all live organisms in water. They are meant to operate continuously to ensure the safety of the water you use. Due to the fact that a UV purifier is not a filter, no wastewater or debris is left behind to clean. The UV system purifies every drop of water that enters.

Advantages and Disadvantages of a UV Water Purification System


  • No Chemicals
  • Does not affect the taste or smell of the water
  • Very low maintenance
  • No water is wasted during the treatment process
  • Highly effective at killing microorganisms
  • Reliable
  • Environmentally friendly
  • Cost-effective
  • Processes water quickly
  • Safe
  • FDA Approved


  • Does not filter out contaminants or dead microorganisms
  • Raises the water temperature
  • Requires electricity to function
  • Will not work on cloudy or muddy water (The light can’t pass through it)