Our editors independently research, test, and recommend the best products; As Amazon Associate We may receive commissions on purchases made from our chosen links

How Water Purifier Works? | Everything you need to know

Water purifiers have become an essential item for every kitchen in India 2023 . These come in different varieties and inhabit different technologies. Thus, they have distinct working mechanisms.

The science behind a water purifier can be uninteresting. But, it is necessary to be aware of it. The reason being that not every water purifier is suitable for you. Water comes to us from different sources and it needs different treatments.

In this article, you’ll know how water purifiers work without going into the geeky part. We’ve simplified each mechanism separately for your better understanding and decision making.


Types of Water Purifying Systems

There are seven different types of water conditions. Naturally, one technique cannot cleanse all kinds of water. In addition to this, various technologies also yield out different kinds of water.

So, it is significant for you to choose wisely amongst them. Every system has a different way of working. They come with their benefits and limitations.

How does a RO water purifier work?

RO water purifier

The reverse osmosis(RO) water purifier involves passing the water with high pressure through a thin membrane. This thin-film composite membrane blocks out any containment in water. This includes solids like salts, chemicals, ions, pesticides or microorganisms present in the water.

It consists of a pressure pump that enables the water to pass through the semipermeable membrane. The RO membrane can filter contaminants up to the size of 0.0001 microns. This means it can filter out teeny-tiny particles not visible to the human eye.

It also has pre-filters and post-filters to remove dirt, chlorine and other sediments. There is a storage tank for the purified water. And the wastewater passes through the drain line.

Benefits of an RO water purifier:

  • RO is so far the best available technology to purify water. The best advantage is that it can remove all unwanted particles from water.
  • An RO purifier is easy to install. The purchasing cost of a RO purifier is also reasonable in India 2023 .
  • RO technology is best for places that receive hard water in taps. The RO removes all the hardness of the water and makes it soft, and safe to drink.
  • RO water is also considered better for cooking food or making beverages.

Limitations of an RO water purifier:

  • In the process of removing undesirable solids, an RO water purifier can remove all the desirable minerals. These minerals are essential for the body. Their deficiency can cause several diseases.
  • RO water purifier makes the water a bit acidic which can be detrimental to health.
  • RO water purifier also produces a lot of wastewater. That is why it needs regular cleaning of the system and proper maintenance.
  • The filters need to be changed every 6-7 months in an RO purifier. The RO membrane also needs to change every year.
  • RO purifiers require a continuous supply of electricity while they are undergoing the filtration process.


How does a UV water purifier work?

UV water purifier

An Ultra Violet(UV) water purifier uses the ultraviolet disinfection system. It is a highly effective chemical-free water purification system. Water passes through a UV purification system in three stages.

  1. It passes through a set of pre-filters for clarification. These make sure that the water is clear enough for effective purification by removing dust and other sediments.
  2. An activated carbon filter improves the water’s taste. It also removes any foul smells and impurities like lead and pesticides.
  3. Water enters a stainless-steel chamber which consists of the purifying UV light. UV light has germicidal properties which kill microorganisms. It removes 99.9% of the viruses and protozoans.

Benefits of a UV water purifier:

  • The UV system purifies water as clean as water that is boiled for 20 minutes.
  • It is eco-friendly.
  • It retains all the minerals in the water because no chemicals are used in the process.

Limitations of a UV water purifier:

  • The UV lamp needs to be changed as per the guidelines of the manufacturing company at regular intervals of time.
  • The viruses or bacteria can still be present in a deactivated form in water.

Tip: It is advisable to buy water purifiers with a stainless steel UV light chamber. Some companies might manufacture it with aluminium or other metals which is not advisable.


How does a UF water purifier work?

UF water purifier

The ultra-filtration(UF) technology works in the same way, the roots of a tree suck water and leave the soil behind. The UF system consists of long membranes made of fibre. These fibre membranes can filter out bacteria and viruses up to 0.001 microns.

When water is passed through the hollow membrane, they filter out the contaminants. A UF system can pass out water that leaves behind big solids as well as pathogens that are not visible to the naked eye.

Benefits of a UF water purifier system:

  • No chemicals are used during the process of filtration of water through the UF system. This makes it eco-friendly and safe to use.
  • UF water purifier not only kills the bacteria but also removes their deactivated form from water.
  • Ultrafiltration does not remove the minerals from water, but only the unwanted contaminants.
  • An ultrafiltration water purifier is easy and quick to install.
  • The UF system also does not generate any wastewater.
  • UF purifiers do not require electricity for functioning.

Limitations of a UF water purifier system:

  • Due to the larger size of the pores of the membrane, it might not remove dissolved particles. This can be disadvantageous because of the harmful pollutants present in water.


Additional technologies used in Water Purifiers:

To make their product sound perfect, companies apply additional equipment to their water purifier. Sometimes they prove to be helpful, but sometimes they can be useless as well.


A microfiltration water purifier is one step down from ultrafiltration. Microfilters can clean particles up to the size of 0.1 microns only. It can remove bacteria but the downside is that it cannot remove viruses.

Thus, there is no sense in buying a water purifier with both UF and MF technology. You can use this with RO or UV.

Tip: In popular opinion, it is not advised to buy Microfiltration during these times. Due to the harmful nature of the viruses, it is necessary to get rid of them, even from water. And MF technology is not successful in doing that.


Alkaline filters or pH balance filters:

As the name suggests, these filters are used to make the water more alkaline or to normalize the pH level of water.

Typically, when we use RO purifiers, they can make the water very acidic. So, to balance the acid-base level, the water is passed through an alkaline filter. The only disadvantage of an alkaline filter is that it can make neutral water alkaline and make it taste bitter.

These filters have no use in UF or UV technologies because they do not disturb the pH level of water.


TDS regulator:

RO water purifier companies brought a new concept of a TDS(totally dissolved solids) regulator into their purifiers.According to them, the essential minerals must be retained in the water.

This is how a TDS regulator works:

  1. Water is divided into two parts.
  2. The first part goes under the whole RO filtration process.
  3. But, the other part goes through only the normal filters.
  4. Then, the water from both sources is mixed.

In this way, minerals from water are retained back. But, on the other hand, it is said that minerals absent in Ro water can be retained from the food we eat.



Which water purifier technology is better-UF or UV?

UV is better than UF in many cases. But, it is advised to purchase a UV+UF combo while buying a water purifier because UV kills the bacteria and viruses and UF removes these dead viruses and bacteria from water.


Which water purifier technology should be used when you receive highly polluted water?

A RO purifier is recommended when the water is highly polluted. This is because polluted water has a lot of dissolved salts that we aren’t aware of. So, it is better advised to purchase an RO to be on the safer side.


How much time does an RO take for filtration?

An RO might take up to one hour for filtering 20 litres. Whereas, a UV or UF filter takes up to 30 litres per hour.



Buying a water purifier can be a time-consuming task. But, just like the internet, these water purifying systems are life-savers. They purify water, the most essential component of survival.

We hope that your query to understand the water purifier mechanisms was resolved. Tell us down in the comment section below which technology suits your water the best!

Leave a Comment