How well do water purifiers remove bacteria and viruses?

2022-04-01 01:25:07How well do water purifiers remove bacteria and viruses?
How well do water purifiers remove bacteria and viruses?

When you look at a clear glass of water, will you be able to see anything other than the clear liquid? Usually, if the water is muddy then you may see a slight colour change but your naked eyes won’t be able to see any other impurities or pollutants present in the water. So, the water looks filtered and ready to drink but is it safe to drink that is what you must find out.

Drinking water whether it is supplied by the municipal provider or from a borewell must be purified before using it. It is quite common that water may contain high TDS levels which usually include harmful bacteria and viruses.

It is a proven fact that water-borne diseases are spread due to harmful viruses and bacteria in the drinking water. You must have heard about water-borne diseases affecting people in various parts of the world in different periods. Some of the widely known waterborne diseases are Malaria, Typhoid, Hepatitis A, Cholera and Giardiasis. One of the main reasons for water-borne diseases is the presence of harmful microorganisms.

Even though municipal water providers disinfect water before supplying it, there may be chances that microorganisms are found in the storage tanks and pipes which then get mixed with the water. Hence, it is necessary to purify the water on a household level before using it for consumption and you must consider various factors while choosing the best water purifier for home.

How do you know that your drinking water is contaminated?

Although it is difficult for the naked eyes to notice the impurities present in the water, there are few signs which indicate that the water may not be safe for drinking. Here are some signs which you should look out for:

  1. Check if the water has a weird taste
  2. Check whether the water has an odor
  3. See whether the color of the water is slightly cloudy or muddy

In case you notice any of these signs then your water contamination levels maybe higher. However, if you don’t find any of these signs, it is still advisable to get your water tested for TDS and other impurities to find out more about the pollutants present in the water. Apart from checking the TDS levels or chlorine levels in drinking water, testing the presence of Coliform bacteria is one of the common ways to determine whether the water contains harmful pathogens.

What are the different types of viruses and bacteria found in the drinking water?

Not all bacteria or viruses are harmful to health. However, it is important to eliminate microorganisms before consuming the water. There are various types of pathogens (bacteria, viruses and parasites) which can be present in water and many of which may cause both short-term and long-term health issues when consumed. Some may cause viral fever, stomach ache, diarrhea or some may even have long-term health effects.

According to WHO, here is a list of commonly found microorganisms in water:

  • Bacteria – Coliforms, Legionella, Enterococci, Vibrio, Salmonella, E. coli, Shigella
  • Viruses – Rotaviruses
  • Enteroviruses – coxsackieviruses, polioviruses, echoviruses
  • Parasites – Giardia, Entamoeba, and Cryptosporidium

These microorganisms have to be filtered from the water to make it safe for drinking. So, how to remove pathogens from the water?

Water purifiers are your best bet!

What are Water Purifiers?

Clean and pure drinking water is rare to find in this commercialized world. Rapid urbanization and deforestation have led to an increase in the pollution levels of water resources. As a result, the water we consume is also vulnerable due to several harmful contaminants. Hence, it is quite important to purify the water before consumption.

A water purifier can help to remove unwanted biological and chemical contaminants, suspended solids, particulate matter, gases, and pathogens from the tap water. In history, the water was purified using techniques such as distillation, sedimentation, and filtration. Today, the new-age water purifiers are much more evolved in terms of purification technology. Good water purifiers have the potential to remove excessive salts, microbes, minerals, and harmful metals from the water. Therefore making it safe for consumption.

Which are the different types of water purifiers?

You can find a wide range of water purifiers available in the market. Even though the main purpose of these water purifiers is to eliminate impurities from the water, the difference is in the technology which each of these use and the type of impurities each of the technology is capable of treating.

4 Main types of Purification Technologies are:

  1. RO Water Purifiers
  2. UV Water Purifiers
  3. UF or MF Water Purifiers

Gravity-Based Water Purifiers:

The Gravity-based water purifier is one of the effective and simple purification methods. It is specifically designed to remove visible dust particles and other particulate matter from the water. Additionally, gravity-based water purifiers can remove viruses and bacteria with the help of an activated carbon module. The reason why it is called a Gravity-based purifier is that it utilizes the force of gravity along with a water filtration system to filter the water. Interestingly, these water purifiers do not require electricity or continuous running water like other purifiers.

RO Water Purifiers:

RO or Reverse Osmosis is one of the most advanced water purification technologies because it can remove a high percentage of impurities, especially TDS in the water. RO uses a semi-permeable membrane along with a multi-stage purification system to eradicate different types of contaminants from the water. TDS (Total Dissolved Solids) which contains minerals, vitamins, harmful metals, chemicals, biological contaminants, particulate matter, suspended solids, and pathogens are removed with the help of RO technology. It requires electricity to work and it is designed in such a way that all types of impurities are removed before sending out completely purified water.

UV Water Purifiers:

UV or UltraViolet Water Purifiers are mainly utilized for removing pathogens (bacteria, viruses, and parasites) present in the water. UV as the name suggests uses UV rays to deactivate the microorganisms and provide safe drinking water. UV water purifiers also run with the help of electricity. Usually, UV technology is often combined with RO technology like RO + UV water purifiers to carry out the complete purification process with the help of one purifier. The presence of UV technology will ensure that the water doesn’t contain any harmful microbes.

UF or MF:

Ultrafiltration or Micro Filtration is often an extended purification process in RO water purifiers. They act as additional filters which will remove any particulate matter or any impurity which is still present in the water after advanced purification like RO. The UF or MF will ensure that the water is completely purified by removing the leftover impurities in the water. Therefore, sending out completely purified and safe water.

However, you may wonder whether all purifiers have the potential to remove all types of impurities?

The answer is no. Each of these technologies is specifically designed to remove a particular type of impurities. However, compared to other technologies, RO water purifiers can remove a wide variety of contaminants present in the water. Hence, many prefer to buy RO water purifiers for their household use.

Do all water purifiers remove bacteria and viruses?

The answer is no. Even though several brands claim that their water purifiers eliminate microbes from the water, it can’t be considered true unless it is UV water purifiers. Yes, among various water purification systems, UV water purification is specifically designed to kill the microorganisms present in the water. Other water purification systems like RO are effective in removing various contaminants but they also need UV filters or technology to take out the pathogens from the water.

What are UV Water Purifiers?

Ultraviolet or UV water purification is one of the most effective ways to eliminate pathogens from drinking water. It works with the help of UV radiation which attacks the microbes. Therefore, disinfecting the water. UV water purifiers can purify water or kill germs without adding any chemicals to the water or changing the taste or odor of the water.

How do UV Water Purifiers work and remove Bacteria/Viruses?

UV water purifiers or Ultraviolet purification systems contain a UV lamp or light. When the water containing pathogens flows into the UV filter, the UV lamp is automatically activated and the rays from the UV light begin to fall on the water. The microorganisms (viruses, bacteria, and parasites) moving in the water are attacked by the UV rays. As the radiation from the lamp directly penetrates the DNA of the microbes, they are killed and also stop them from regenerating.

Once the water is disinfected, the purifier sends out clean and safe water. The UV purification system is said to be effective in killing 99% of the germs present in water and that too without adding any chemicals. UV is one of the technologies which can remove microbes that can’t be removed even with chlorination. It can also remove cysts like Giardia and Cryptosporidium. Hence, UV water purification is one of the effective and environmentally friendly methods to purify and eradicate pathogens from the drinking water.

Benefits of UV Water Purifiers

There are various advantages of using UV water purifiers:

  1. It is one of the safest and simplest methods of treating microorganisms in water.
  2. By installing a whole-house UV disinfection system, you can ensure to purify both cold and hot water at home.
  3. It is an advanced and environmentally safe purification method which is capable of destroying 99% of microorganisms, including cysts present in the water
  4. UV water purifiers are budget-friendly and also energy-efficient
  5. The annual maintenance of UV purifiers are cost-effective and the UV lamp replacement is the only maintenance that is required for these purifiers


When choosing the best water purifier for your home, you must consider several factors like the TDS levels in the water, whether the water has any other harmful pollutants, and the percentage of pathogenic bacteria in the water. If the TDS levels are high then you have to opt for RO water purifiers and if the TDS levels are low but contain more pathogens then you have to choose UV water purifiers. However, in the current scenario, whether you get tap (municipal-treated water) or borewell water, it is important to purify it using multi-stage purifiers like RO+UV+UF to ensure that the water is treated thoroughly and safe for drinking water.