How does Ultraviolet Water Purification Work?

You have likely heard the term UV rays being used quite often. UV lights are generally used for sterilization. They are mostly used in tanning meds, inside black lights, and to sanitize medical equipment.

So, can we harness this sterilization powers for water purification?

Of course!

Ultraviolet water purifiers have been around for some time and can provide highly effective disinfection for your water supply. Scroll on to learn exactly how this system works as well as its advantages and disadvantages.

How does UV Water Purification work?


UV water purifier works to remove the harmful microorganisms that may be contaminating your water supply. It can target bacteria, viruses, and even cysts like cryptosporidium. It kills off germs in your water supply and can also disrupt the DNA of these microorganisms. This disruption prevents them from reproducing and helps turn these germs inactive.

Elements of a UV Water Purifier

A typical UV water purifier consists of four main elements. These are described in detail as follows:

1. The Reactor Chamber

The reactor chamber is the outer box that houses all the internal parts. Furthermore, it helps control the water flow through the system. The build is generally stainless steel, but other materials can be used as well. The shape and size of this chamber will mostly affect the outlook of your UV purifier, not its performance.

2. The UV Lamp

The UV lamp is the star of the system. Typically, they all tend to look the same as they have a similar function. These lamps emit UV-C radiation, which is ideal for its disinfection purposes. Small beads form the majority of these lamps and are full of mercury vapor. This vapor acts as the fuel for this lamp.

Similar to a regular light bulb, these UV lamps come with a filament. This filament produces an electric current that heats up until the contained mercury reaches a certain temperature. Once heated, the mercury evaporates and creates the electrical arcs that produce germicidal UV-C radiation.

3. The Quartz Sleeve

The quartz sleeve is the part of the water purifier that holds the UV lamp. It is a slender, cylindrical tube made from quartz glass. It exists to protect the UV lamp inside. As the contaminated water surrounds the lamp, this sleeve will act as a barrier and extend its lifespan. It is also relatively easier to clean and maintain.

4. The Controller Unit

The controller unit is what controls this entire operation. They usually sport a simple build and help supply power to the lamp. There are more complicated controllers that can offer a wider variety of functionality. This variety can include timers, low-UV alarms, as well as indicator lights for maintenance. You can choose a UV water purifier that best fits your needs.

What is the Intensity Limit for a UV Water Purifier?

UV intensity refers to the amount of radiation that is actually being emitted into your water supply. But how much intensity is really being generated within the confines of your water purifier?

This intensity can be measured on the basis of the number of bacteria that it can treat. The upper limit for a typical UV light is removing 1000 total coliform per 100 mL of water. This range is also 100 fecal coliform/100 mL.

What does UV Water Purification Remove?

Image Source: Click Here

A UV water purifier is installed mainly to target living impurities. It boasts of a 99.99% effectiveness in deactivating the harmful microorganisms in your water supply. It is not very effective at removing other particle impurities. The following are the microorganisms that UV disinfection protects you from:

  • Salmonella
  • E. coli
  • Cholera
  • Dysentery bacilli
  • Hepatitis B
  • Algae and Fungi
  • Cryptosporidium (Parasite that infects intestinal tract)
  • Streptococcus
  • Mycobacterium tuberculosis
  • Some viruses

When do I need to use a UV Water Purifier?

There is hardly ever a time when you don’t need water that is safe from germs. However, as the municipalities usually provide a fairly high-grade filtration, individual UV disinfection is not necessary for most places.

You should consider getting a UV water purifier if your area is prone to receiving water with any microorganisms. It is also a good protection to have in case of a natural disaster. Furthermore, if you are using water from your private well or long-term storage, there is a high chance of microbial growth.

In case the water from your city supplier becomes contaminated, a UV water purifier can make sure you have a running supply of safe drinking water.

Is UV Water Purification Safe?

A UV Water Purifier needs only a UV lamp to disinfect your water. It does not add any harmful chemicals to your water. Chlorine is another common disinfectant, but it cannot remove some microorganisms, such as protozoa. Furthermore, chlorine purification will require a retention tank as well as for you to keep track of the solutions inside.

The only element UV water purifiers utilize is the mercury present inside the lamps. Mercury is generally considered to be dangerous to us. However, in a UV lamp, the size of a mercury bead is so minuscule that it is essentially negligible. This means that you are in no danger of any exposure, and your UV water purifier should leave you with safe and clean drinking water.

UV systems are much more convenient to use and require very low maintenance. The thing to keep in mind is that the UV-C radiation can be harmful to humans as well. However, these lamps are well covered. Just make sure not to touch or look at the bulb while it is on, and you should be just fine.

Advantages of UV Water Purification

A UV water purifier comes with many advantages. Some of these are listed as follows:

  • No chemicals required for disinfection
  • 99.99% effective at deactivating germs
  • Low-maintenance
  • Requires minimal energy
  • No wastewater or debris to clean out
  • Affordable and effective
  • Does not add any odor or bad taste to the water

Disadvantages of UV Water Purification

While the disadvantages are far and few in comparison, no system is perfect. Here are some of the disadvantages of UV water purification.

  • Only targets living contaminants
  • Needs a separate filter for pure water without any impurities
  • Requires electricity to function
  • The UV lamp can heat up the water

How to maintain your UV Water Purifier?


The best thing about owning a UV water purifier, other than the germ-free water, is the hassle-free maintenance. These purifiers are built to last for many years. There are only a couple of things you need to do to keep them running smoothly.

1. Replace the UV Lamp Annually

There is a limited amount of mercury fuel in these UV lamps. This amount decreases every time the lamp is used. On average, a single UV lamp, assuming 24-hour of run-time, should last you about 9000 hours or 375 days. This value means that you will need to replace the lamp about once every year to keep your water supply safe.

2. Make Sure you Clean the Sleeve

The quartz sleeve is the only barrier that the UV lamp has from the contaminated water. If this clear glass tube is contaminated, it can prevent the UV lamp from providing effective disinfection. So whenever you change the UV lamp, make sure you give the sleeve a swift cleaning.

3. Replace the Quartz Sleeve Every Two Years

There is only so much cleaning that can leave your quartz sleeve in the pristine condition it came in. Moreover, these sleeves can be quite fragile. It is, thus, a good idea to have an extra sleeve handy and also replace it every two years.

Frequently Asked Questions

1. How long does it take for a UV lamp to kill bacteria in the water?

A UV lamp will take about ten seconds to kill the average bacteria. In this estimation, the distance of the bacteria from the lamp matters. The range covered is about six inches from the lamp.

2. How Effective is UV Water Purification for Well Water?

UV water purification is the most effective method for disinfecting well water from bacteria. These rays are highly capable of penetrating all the harmful pathogens that may have seeped into your well water.

3. How do I reset my UV lamp?

Most UV lamps can be reset by disconnecting the purifier from its power source. After this, wait for fifteen seconds and reconnect it to the power supply. The purifier should emit a three-second beep to indicate that a reset has been successful.

In Summary,

Ultraviolet water purification is a highly effective method to keep your water free of 99.99% pathogens. It follows a simple mechanism that is easy to maintain and comes with a variety of advantages. Furthermore, it does not add any chemicals or bad odors to your existing supply. A UV water purification, thus, leaves you with pure and safe drinking water.