Groundwater is not the purest form of water.

It has visible and invisible impurities. It comes with a generous proportion of TDS. Hence, the taste seems brackish or salty.

Water from natural sources like rivers and lakes get contaminated with the human, plant, animal, and industrial waste.

Municipalities add chlorine or fluorine to the groundwater to get rid of viruses and bacteria.

Despite these efforts, our tap water contains harmful chemicals.

Therefore, installing a high-quality water purifier should be a priority for every home in India.

We highly recommend you to read the Water Purifier Buying Guide at the end of the article to get in-depth knowledge about all the latest water purification technologies.

In the meanwhile, we shall look at some of the best water purifiers available in India in 2020

Best Water Purifier in India

1. Kent New Grand 8L RO + Double UV + UF + TDS Controller

Kent is one of the top brands of water purifiers available in the Indian market. This trusted brand has many models that are suited for Indian homes and offices. This water purifier comes with patented Mineral RO technology and an inbuilt TDS controller.

The Kent New Grand appliance comes with a multi-stage purification process to ensure delivery of pure water.

The RO purification process ably supported by UV and UF ensures the elimination of visible and invisible pollutants like viruses, bacteria, TDS, and other heavy metals.

The patented Mineral RO technology ensures to retain the essential minerals using the services of TDS controller to provide high-quality purified drinking water.

The water filter features a unique technology, Save Water Technology that reduces unnecessary wastage of water in the RO water purification process. This computer-controlled mechanism helps in recovering more water as purified, as compared to the earlier Kent RO water purifier models.

This water purifier comes with a water level indicator to keep track of purified water available in the storage tank. Thus, you can switch on the machine whenever the water level drops down.

Kent Grand water purifier can purify water from all kinds of water sources. Hence, it is an ideal appliance to have in rural, urban, and coastal areas, as well.

The water purifier features an 8-litre water storage tank. It can purify at a rate of 20 litres per hour, thereby ensuring a continuous supply of pure water.

Kent Grand has all the qualities that the best water purifier should have.

  • Patented Mineral RO technology
  • New Save Water Technology
  • Multi-stage purification
  • Adequate storage capacity
  • Filters need regular replacement thereby increasing the overall cost

2. AO Smith Z9 Green RO 10L RO + SCMT Water Purifier

AO Smith is a reputed international brand of water purifiers available in the Indian market at affordable prices.

One of the significant advantages of AO Smith Z9 water purifier is the patented Advance Recovery Technology.

This technology allows the appliance to save two times more water than the standard RO water purifier. It also ensures minimum wastage of essential minerals during the RO purification process.

The 8-stage water purifying process includes RO + SCMT technology along with MIN-TECH. SCMT ensures secondary microbial purification to ensure there is no recontamination of pure water by harmful microbes.

MIN-TECH adds back the essential minerals that get lost during the RO purification process. Thus, AO Smith Z9 Green ranks as one of the best water purifiers in India in 2020.

The additional advantage of this water purifying system is that you have a choice between obtaining pure water at 450C and 800C at a press of a button. This hot water is ideal for cooking, whereby you do not have to heat the water again.

With AO Smith Z9 Green water purifier, you do not have to search for the controls, as this purifier has a Night Assist feature to locate the appliance. The digital display provides useful information such as water temperature, full tank indication, and filter alerts.

The water level indicator is a handy tool to help you judge the level of pure water in the 10L food-grade water storage can. Another innovative feature is the presence of a drip tray that ensures you do not mess around the place with water spillages.

The aesthetic looks of the AO Smith Z9 Green water purifier make it one of the best purifiers for water with TDS levels up to 2000ppm.

  • Hot and cold-water options
  • Aesthetic appearance
  • Less wastage of water
  • Low power consumption
  • Water refill process starts only when the water level reaches 50% capacity
  • Unable to dispense water in the absence of electricity

3. HUL Pureit Copper+ Mineral RO + UV + UF 7-Stage water purifier

Copper has water purification qualities. It explains why our forefathers used copper vessels for storing water. HUL Pureit uses the same principle in designing this water purifier.

This appliance infuses the health benefits of copper in 100% RO purified water. Thus, you have one of the best water purifiers for home working day and night to ensure an uninterrupted stream of pure and healthy water for your family.

The water purification consists of a seven-stage process that includes the use of,

  • Pre-sediment filter to remove large impurities
  • Pre-RO activated carbon filter for eliminating bad odour and organic contaminants
  • Wire mesh filter to trap the significant soluble pollutants
  • RO membrane to carry out 100% water purification
  • UF membrane to remove the traces of any TDS that manage to seep through
  • UV reactor to get rid of bacteria, viruses, and other microorganisms
  • Post-RO activated carbon filter to enhance the taste of water

This water purifier comes with a dual water dispensing option. You get pure RO water as well as copper-charged RO water, thereby enabling you to enjoy the medicinal benefits of copper.

The system ensures infusing the right amount of copper in every glass of water.

The water purifier is an intelligent one, as it smartly senses and schedules auto cleaning, thereby ensuring the supply of fresh copper at all times.

The appliance comes equipped with an 8L water storage tank that should prove adequate for an average Indian family.

HUL Pureit water purifier comes with additional features like Double Purity Lock that ensures the machine does not dispense a single drop of unsafe water.

The Advance Alert System alerts you 15 days before the expiry of the Germkill Kit. The Auto Shut-Off feature shuts off water purification and supply after the expire of the Germkill Kit.

  • Advantage of copper purification
  • The 7-stage water purification process
  • Automatic shut off feature
  • Wastes around 650 ml for every litre of water during the RO purification process

4. Blue Star Majesto MA4BSAM02 8L RO + UV Water Purifier

Blue Star is a reputed manufacturer of consumer durables, especially the air conditioning systems and refrigerators. The Blue Star brand of water purifiers is also one of the best water purifiers in India in 2020 for hard water purification.

This feature-loaded water purifier is ideal for handling input water sources having TDS levels up to 2000.

One of the highlights of this water purification system is the use of Aqua Booster that enhances the taste of RO purified water by replenishing the minerals lost during the purification process.

The double-layered water purification method ensures a supply of 100% pure and safe water to drink. This water purifier comes with sufficient storage up to eight litres that should be enough for an average Indian family.

The six-stage water purification process consists of,

  • Pre-filter to trap large insoluble contaminants
  • Pre-carbon filter to eliminate bad odour and organic waste
  • Sediment filter to remove large-sized soluble pollutants
  • RO membrane to get rid of TDS and heavy metal impurities
  • UV lamp to take care of microorganisms
  • Post-Carbon filter with Aqua Taste Booster to enhance the taste of purified RO water

The post-carbon filter comprises of copper-impregnated carbon, thereby ensuring that you get the benefit of the medicinal uses of copper. This sleek and stylish water purifier comes in two modes, wall-mountable and allows placing on a countertop.

Other notable features include a tank-full indicator that automatically stops the supply of water to the appliance. The child-lock feature is a useful one, as it prevents your children from fiddling with the water purifier controls.

The Majesto should be an ideal addition to your modern kitchen because of its exquisite looks and performance.

  • Child-lock feature prevents accidental spillover
  • Aqua booster enhances the taste of water
  • Good performance with sleek looks
  • No TDS controller or Mineraliser feature to replenish lost minerals during RO purification

5. Faber Galaxy RO + UF + MAT – 7-stage water purifier

Faber Galaxy water purifier comes with an innovative Mineral Enhancement Technology known as MAT to deliver 100% pure and healthy drinking water for your entire family.

The company claims that it can handle water with TDS levels up to 2500. Therefore, it should rank as one of the best water purifiers in India for hard water.

This water purifier comes in a wall-mountable design with a storage tank capacity of nine litres to ensure an adequate supply of water for the entire family. The seven-stage water purification process includes the following.

  • External sediment filter to eliminate contaminants up to the size of 20 microns
  • The pre-carbon filter to remove pollutants like chlorine and other volatile organic compounds
  • The sediment filter removes impurities up to the size of 5 microns
  • The RO membrane takes care of heavy metal impurities and comes with a Germ
  • Eliminator membrane designed to work with high TDS level up to 2500 ppm
  • The post-carbon or MAT filter enhances the taste of water
  • The UF membrane removes cysts and bacteria to maintain the mineral content of water with the use of TDS controller

This water purifier features Copper Guard Technology that acts as an anti-fouling agent to ensure delivery of pure, hygienic water. The Mineral Addition Technology infuses back the essential minerals lost during the purification process.

The water filter can work with all kinds of water, including groundwater, borewell water, municipality-treated water, and so on. Hence, it is an ideal one for use in homes as well as offices.

  • The high storage capacity of nine litres
  • Mineral Addition Technology to replenish lost minerals
  • 7-stage filtration process
  • Elegant appearance
  • Does not come with UV purification

6. LG Puricare WW150NP RO + UV Water purifier

LG is a renowned consumer appliance manufacturer in India. The success of LG air conditioners, TVs, and refrigerators should be proof that Indian consumers trust LG to deliver exceptional performances. This LG Puricare water purifier does not disappoint in any way.

The WW150NP water purifier comes with a dual protection stainless steel tank that maintains the freshness of water while reducing the growth of bacteria and algae.

This water purifier features a 5-stage RO water purification process that includes the use of a UV lamp to eliminate harmful germs and bacteria from RO purified water to make it absolutely safe for drinking.

At the same time, it also ensures to maintain the mineral content in the purified water at all times.

The most significant advantage of this water purifier is the Stainless-Steel Certification that proves that the water storage tank has 94.4% less E-coli growth in 24 hours as compared to plastic and fibre tanks.

This water purifier has an advanced RO water purification technology that removes viruses and bacteria at the purification stage, thus obviating the need for a UV lamp at the purification stage.

However, the UV lamp proves handy during the water-preservation phase, thereby ensuring dual protection. The UV purification cycle starts every six hours.

This water purifier employs the most hygienic way of purifying water using digital sterilisation without any harmful chemicals. However, one should ensure to used LG-certified filters and genuine spare parts to retain the efficiency of the product.

Other useful features include a filter change indicator to alert you whenever a change of filter is due. This LG water purifier is one of the best water purifiers under Rs 20,000.

  • Dual protection water purifying system
  • Does not mix impure water to control TDS levels like some water purifiers do
  • One of the best water purifiers for groundwater
  • Excellent looks complemented by fantastic performance
  • Does not have UV at the purification stage but compensates during the preservation stage

7. Faber Galaxy Plus RO + UV + UF + MAT 9L water purifier

This Faber Galaxy water purifier is better than the one discussed earlier because of its 8-stage filtration process.

The purification process includes a UV filtration procedure to take care of harmful germs and bacteria at the final stage of water purification. This enhanced level of water purification ensures that it is one of the best water purifiers available in India under Rs 15,000.

The highlights of this water purifier include its elegant designing that blends well with your kitchen décor and makes the water purifier look a part of the modern kitchen.

The RO membrane is an advanced one that can handle water with TDS levels as high as 2500ppm. Therefore, it should qualify as one of the best water purifiers for all sources of water, including groundwater, borewell water, and municipality-supplied drinking water.

The Faber Galaxy Plus water purifier comes with an 8-stage purification process that includes RO, UV, and UF processes, thereby ensuring the supply of high-quality pure and hygienically safe water.

This water purifier has the additional advantage of MAT technology to enhance the taste of purified RO water. This Mineral Addition Technology helps in adding essential minerals that get lost during the RO water purification process.

Another excellent feature of the Faber Galaxy Plus water purifier is the Copper Guard technology to eliminate foul odour from the pure water. The high storage capacity of nine litres should prove adequate for the entire family.

The ABS Food Grade Plastic tank also ensures to maintain the purity level of water during its storage.

  • Fabulous design that enhances the look of your modern kitchen
  • 8-stage filtration procedure including Ro, UV, and UF
  • Can handle TDS levels up to 2500 ppm
  • Service Quality is not up to the mark in some areas

8. Havells Max-Alkaline 7-litre RO + UV Water Purifier

Havells Max water purifier has a fantastic design, as it enables you to place the water purifier at the corners. The other water purifier designs discussed here have a rectangular shape that makes it challenging to place at the corners of the kitchen. Hence, this design has an advantage over the other water purifier designs.

Users can save a lot of space with Havells water purifier. On the performance front, the Havells water purifier ranks as among the best water purifiers in India in 2020 because it comes with fascinating features.

This Havells water purifier features a 7-stage water purification process that includes RO and UV water purification. It contains the standard sediment filter, activated carbon pre and post RO filtration, RO membrane, and Ultraviolet lamp water purification.

Alkaline water has specific health benefits. This Havells water purifier comes with Mineralz Technology that adds natural minerals with trace elements to enhance the pH value of the purified water.

The Revitalizer feature ensures to improve hydration and mineral absorption, thereby improving the taste and quality of the purified water.

Some of the other handy features include the self-diagnostic friendly alerts, tank-full indicator, and error alerts for UV, SV, and pump failure.

All RO water purifiers waste a lot of water during the water purification process. This RO water purifier is not different in this regard. Havells suggests reusing the wastewater for washing utensils, clothes, and for gardening purposes.

  • Excellent design that permits users to hang the appliance at the corners without affecting its utility
  • 7-stage water purification process including UV
  • Revitaliser and Mineralz technology to enhance the pH value and improve alkalinity
  • Maintenance can be expensive as with other RO water purifiers

9. Kent 11087 Pride TC Mineral RO Water Purifier

This Kent 11087 Price TC RO water purifier also belongs to the top drawer. It comes with excellent features like RO membrane and UF technology to provide high-quality purified water to its users.

The Kent 11087 Pride water purifier should classify as the best water purifier for municipal water because many municipalities take care of treating the germs and bacteria present in the water at their end before distributing it to the residents of the city.

This water purifier comes with a wall-mountable design and double purification technology that comprises of RO and UF coupled with the use of TDS controller at the final stage.

The RO membrane ensures to eliminate contaminants as small as 0.0001 microns, thereby removing all the heavy metal impurities like lead, arsenic, and mercury from the water source. UF technology provides additional protection from harmful microorganisms.

Kent Pride TC water purifier works on Mineral RO technology that helps in retaining the essential minerals using TDS control. This water purifying appliance can treat water from all sources, including borewells and municipality distributed water.

The device also works well in areas that have brackish water, especially coastal areas.

Kent Pride TC water purifier features ABS Food Grade plastic to keep the storage tank and other parts free from corrosion, thereby enhancing its durability quotient.

The fully automatic working feature entails that the appliance stops working after filling up the water storage tank. It starts working automatically as you use the water from the container.

The storage capacity of eight litres is ideal for a standard Indian family. It ensures that the family can get pure water even in the absence of electricity. Thus, this water purifier is useful in areas where there are high incidences of power outages.

  • High-quality water purification performance
  • Capable of purifying all kinds of source water
  • Fully automatic operation
  • Ideal for places where there is a low level of biological contamination
  • No UV lamp to eliminate microorganisms in water

10. Eureka Forbes Aquasure – RO + UV + MTDS Water Purifier

Eureka Forbes is among the earliest manufacturers of water purification appliances in India. This model from Eureka Forbes comes with state-of-the-art purification processes like RO, UV, and MTDS, thereby ensuring the supply of pure and hygienic water to its users.

The Aquasure model employs multi-stage purification that is a combination of RO and UV.

The water purifier comes with long-lasting cartridges that can sustain its quality for more than 6000 litres. During the RO water purification process, the essential minerals get lost as well as the heavy metal contaminants. Therefore, the resultant water is pure but lacks nourishment.

The MTDS feature ensures to replace the lost minerals with essential salts like magnesium, calcium, and potassium to enhance the hygienic value of water.

This Aquasure water purifier comes with a large storage tank having a capacity of seven litres that should prove enough for a regular Indian family.

The energy-saving mode cuts off the supply of power to the appliance when the storage tank becomes full. It starts the device again when the water goes below the minimum level. Therefore, it counts as one of the best water purifiers that can save power.

It comes with a sleek design that adds a lot of glamour to your kitchen. The system is such that it is possible to place the water purifier on the kitchen countertop or hang it from the walls, as well.

Eureka Forbes has an extensive service network, whereby it becomes easy to service the appliance in case you face problems with the same.

  • Excellent service network
  • Impeccable performance
  • One of the best water purifiers under Rs 10,000
  • As with other RO water purifiers, this appliance wastes a lot of water during its purification

11. Kent Maxx 7-litres Wall Mountable/Table-Top UV + UF water purifier

Not all places in India have source water with TDS levels greater than 500. Many areas have good quality water with low TDS levels. However, such water can contain biological contaminants, visible, as well as invisible. Under such circumstances, you do not have to invest in an RO water purifier. A simple appliance with UF and UV filtration can do the job for you. This Kent Maxx water purifier is one such appliance.

This water purifier uses double water purification that includes UV and UF to make the water pure and safe to drink.

The UF membrane takes care of sediment impurities and other dissolved pollutants. The UV lamp ensures to kill germs and other microbes to make the water safe and hygienic to drink.

The water purifier comes with a detachable tank that you can carry along with you on a picnic. Thus you have pure and safe water with you at all times. This appliance comes with computer-controlled operational features like filter change and UV change alarm.

Kent Maxx water purifier is different from other Kent water purifiers as you can place this water purifier on a countertop, as well. You do not have this facility on the Kent Grand Plus or Kent Pride TC water purifier.

Kent Maxx water purifier with ABS Food Grade Plastic that maintains the quality of water. The push-fit design of the Maxx water purifier prevents leakages, as well. It comes with a seven-litre tank that should have the adequate storage capacity to cater to emergency situations like power cuts.

The transparent design adds to the attraction quotient by making it visually appealing. It is one of the best water purifiers under Rs 8,000.

  • High-quality performance
  • Ideal for places where the TDS levels are below 500 ppm
  • Aesthetic design that adds glamour to your kitchen environment
  • PAN India service network available
  • Not the best appliance when it comes to dealing with TDS levels above 500 ppm
  • Does not remove heavy metal impurities like lead, arsenic, and mercury

Water Purifier Buying Guide

Why do you need a water purifier?

You have hit the nail right on the head by asking this question. The water that is available in our taps is not exactly the best one to drink directly.

This water contains all kinds of contaminants one can imagine. It explains why many people boil water before drinking.

Boiling kills the germs, viruses, and bacteria from the water. At the same time, it kills the taste and flavour, as well but does not remove the salts from the water.

Therefore, one can resort to using water purifiers that can deliver high-quality drinking water that surprisingly, tastes good, as well.

Now the ‘Why’ part of the question is out of the way. Let us now concentrate on what to do before purchasing your water purifier.

Test the tap water

Of course, there are two ways of testing the tap water. One is to use your natural instincts, and the other is a scientific way with the use of a TDS meter or what we refer to as a water testing kit.

The natural way is to smell and taste the water. If it smells or tastes awful, you should go ahead and read the rest of the article.

At the same time, if it smells and tastes good, what should you do? You should still go ahead and read the article thoroughly.

Water that smells and tastes good is not necessarily the healthiest to drink.

Tap water in India contains soluble and insoluble impurities. Despite the municipalities purifying groundwater, the water can pick up contaminants on its way to your home.

It has to pass through pipes and tanks. Pipelines and tanks can be corroded. They can also have a mineral build-up. Both of these factors affect the quality of water.

Secondly, groundwater can have impurities like arsenic, antimony, lead, and so on. It can also contain Totally Dissolved Solids (TDS – we will be using this term frequently throughout the article).

TDS can comprise organic and inorganic salts including calcium, magnesium, potassium, chlorides, bicarbonates, and sulphates. Thus, it is good to use a TDS meter to determine the extent of TDS.

Where can you test the water?

You do not have to go to a laboratory to conduct the test. The TDS meter is a simple tool to use. It gives reasonably accurate results that should enable you to decide the type of water purifier you should have in your home.

How do you use the TDS meter?

A digital TDS meter should not cost more than a few hundred rupees. Invest in one, as it will prove useful to you for life. Here is how you use the TDS meter.

Step 1 – Determine the temperature of water in the following way

  • Switch on the TDS meter and press the TEMP button.
  • Place the meter inside the glass of water and note down its temperature.
  • Return to the TDS mode by pressing the TEMP button again.

Step 2 – Measure the TDS level

  • Remove the protective cap of the TDS meter and turn the TDS meter on.
  • Immerse the TDS meter in the glass of water up to the maximum immersion level marked on the device.
  • If there are any bubbles in the water, stir it gently to get rid of them.
  • Wait for about 10 seconds and allow the reading to stabilise.
  • Press the HOLD option and remove the device to note down the reading.

Now, you have the reading. What should you do now? This table will give you a good idea about what the reading conveys.

TDS Level Reasons for acceptability or Non-acceptance
Less than 50 Water with such a low level of TDS does not contain any essential minerals. It will be tasteless. It is not an acceptable range.
50 to 150 It is an acceptable level. However, if you have an RO water purifier at home, ensure that the TDS level is not below 80
150 to 200 This level is acceptable. Hospitals usually have this level of TDS in their water supply. It is ideal for maintaining cardiovascular fitness
250 to 350 Most of the Indian homes have tap water in this range. It is an acceptable range
350 to 500 BIS guidelines state that TDS levels up to 500 are acceptable.
500 to 900 As this level is not acceptable, use an RO water purifier with TDS controller/mineraliser.
900 to 1200 It is better to use an RO water purifier of good quality with TDS controller.
1200 to 2000 It is a highly unacceptable range. You will need an excellent RO water purifier that can handle water with TDS levels up to 2000.
Above 2000 Most of the RO water purifiers in the market cannot handle such a high level of TDS.

We shall now look at the type of water purifier you should buy depending on the TDS level in the source water.

TDS Level Water Quality Viruses/Bacteria Ideal water purifier
Below 500 Good Yes UV water purifier should be sufficient
Below 500 Muddy/turbid Yes Go for a UV + UF water purifier
Above 500 Good Yes RO + UV water purifier with TDS controller/mineraliser should be okay
Above 500 Muddy/turbid Yes RO + UV + UF water purifier with mineraliser/TDS controller should be ideal
Above 2000 NA NA Unfit for domestic consumption

You have done your homework correctly. Now, you know the TDS level as well as the water quality.

You should go ahead and purchase the ideal water purifier. Let us now discuss what these specific terms, TDS, UV, UF, RO, and so on signify. It will help you understand the basics well.

TDS – Totally Dissolved Solids

TDS can come in various forms. We shall now segregate our population into three distinct types

Rural Population Urban PopulationCoastal population

People living in villages and relying on natural sources of water

Village folk usually do not get piped water supply from municipalities. They rely on natural sources of water such as wells, borewells, rivers, and lakes.

These people use well water to cater to all requirements, domestic and agricultural.

If you venture into a village, you will find domestic animals like cows, buffaloes, goats, and dogs sharing the well water with humans. Naturally, there can be high levels of contaminants.

Secondly, industries in the vicinity of the villages dump their toxic wastes into the rivers and lakes.

The groundwater resources also get polluted due to the indiscriminate release of harmful metals like lead, arsenic, mercury, and so on. All these impurities, visible and impurities constitute TDS.

However, one should note that not all TDS is bad. The groundwater contains useful minerals like calcium, magnesium, and potassium, but the harmful TDS makes it necessary for village folk to invest in a good-quality RO water purifier and with a TDS controller.

We shall look into this aspect when we discuss RO water purification.

Those having access to piped water supply from municipalities

From the rural folk, we move towards the urban population that depends on municipal water supply. Many people have borewells in their homes.

Such people have an advantage over the rural people because the municipality undertakes the job of purification of water before distributing them to the residents through pipes (underground or over the ground).

Municipalities use RO water purification techniques to eliminate TDS and other contaminants. However, the RO-purified water collects impurities during transit from the municipal tanks to the homes.

Usually, the pipes supplying water to the residents are subject to corrosion, leaks, and rusting. Therefore, these households get water with visible impurities.

A UF and UV water purifier should be enough to purify the water, as the municipality has already taken care of RO.

Homes depending on borewells should determine the TDS levels before choosing the type of water purifier. It is always better to go for RO + UV + UF water purifier to be safe on all counts.

India has a vast coastal area with millions of people depending on salty groundwater for their consumption needs.

This water has a high level of TDS. Therefore, they should prefer the RO + UV + UV water purifier with TDS controller or mineraliser for domestic consumption.

We shall now discuss the different types of water filtering methods such as UV, UF, and RO. The concept should be clear before you decide to purchase the water purifier of your choice.

Different Types of Water Purification Systems

Gravity-based water purification systems

Old-timers will recall the simple water filter that used to be common in all households. It used to consist of two containers placed one over the other.

The top container used to have water filtering candles. One used to fill this container with the source water. The water seeps through the fine holes present in the filtering candles into the container below.

This water purification system is an example of gravity-based water purification. It is a kind of UF process. UF stands for Ultra Filtration.

The modern-day UF filters have such a membrane that can trap visible as well as ultrafine contaminants to provide water of good quality.

Such water filters are best in areas where the TDS levels are less than 500. Such water purification systems do not require any electricity for its functioning.

Ultra-Violet Chamber water purification water systems

About 30 years back, there were no RO water purifiers in India. People used to rely on the UF process for their water purification.

The turn of the twenty-first century saw the introduction of ultraviolet (UV) chambers as an effective method of water purification. UV purification is an effective method, as it can eliminate harmful viruses and bacteria.

The water passes through a UV chamber that serves its purpose by killing the germs and providing healthy water to drink.

Such water purification systems need electricity to work. Secondly, there is a disadvantage because the UV chamber can kill the germs but not destroy the bodies of the viruses and bacteria.

Of course, that should not affect your health in any way. However, it is better to pass such water through a UF membrane to remove the remnants.

Reverse Osmosis – RO water purifier

To understand Reverse Osmosis, one should be conversant with the principles of osmosis.

This requires us to go back to our school days and reopen the biology books. Osmosis is a natural process where a liquid in an area with a lower concentration tends to move towards an area of higher concentration through a semipermeable membrane.

A simple example of osmosis is when you place a potato inside a glass of water. After some time you will find the vegetable swelling up because the water from the glass seeps through inside the potato.

The potato contains a high concentration of starch. The potato skin acts as a semipermeable membrane. The significance of the semipermeable membrane is that it does not allow the reverse flow of water under normal circumstances.

Reverse osmosis is reversing the process of osmosis. In this process, water moves from an area of higher concentration to that of a lower concentration through a semipermeable membrane.

RO water purifiers work on a similar procedure where the impure water with a higher TDS level passes through a semipermeable RO membrane.

The membrane has millions of small pores through which the salts cannot pass through. The water molecules are small enough to seep through thereby ensuring the elimination of TDS.

However, this process requires the application of pressure. Hence, RO water purifiers come with built-in pumps to quicken the process.

We shall now discuss the working principle of an RO water purifier.

RO Water Purifier – Working principle

The RO water purifiers available in the market employ a six-level or seven-level water filtration process.

Sediment Filter
The sediment filter is the first line of defence in an RO water purifier. Usually, the sediment filter is placed outside the RO water purifier machine.

The sediment filter works in a way similar to that of the erstwhile candle filters we had in the late 1980s. The water from the source passes through this sediment filter that takes care of the large impurities.

Hence the water loses much of its turbidity before entering the RO water purifier. It serves a dual purpose. On the one hand, it eliminates the heavy impurities and reduces the load for the RO water purification process. As a result, it enhances the life of the RO membrane.

Pre-Activated Carbon Filter
 The RO water purifier system has the water passing through an activated carbon filter to remove the organic impurities. This filter also helps by removing the unpleasant taste of water.
Reverse Osmosis – RO water purifier
Ultra-Filtration Stage – The UF is the third stage of filtration. The water now passed through the UF membrane to trap soluble contaminants.

The UF membrane consists of tiny pores that can trap microscopic pollutants. Thus, the water becomes relatively free of soluble solids after passing through the UF stage.

Reverse Osmosis Stage
The RO purification is the crucial stage in the purification process. The UF-purified water passes through the RO membrane, thereby resulting in the elimination of all TDS.

This purification process removes the toxic molecules of lead, arsenic, mercury, and other contaminants. It also ensures to remove TDS by more than 99%. Thus, you have TDS-free water emerging from the outlet.

The RO process has a disadvantage in that it wastes a lot of water while squeezing out pure water from the water source. This water flows out of the machine through a separate outlet.

Ultraviolet Purification
 The RO process takes care of TDS and other metallic impurities. It also destroys some of the larger microorganisms, as well.

However, organisms having size less than the pores of the RO membrane pass through the filtration process. This RO-purified water then passes through an ultraviolet chamber that destroys the viruses and bacteria from the water.

Hence, you have pure and healthy water at the end of the fifth stage of purification.

Post-activated carbon filter
 The UV process eliminates viruses and bacteria by killing them. However, it cannot dispose of the dead bodies of these viruses. Secondly, some organic impurities manage to sneak through the process.

Hence, the water passes through a Post-activated filter to remove these dead bodies and improve the taste of water by getting rid of the organic pollutants. The primary function of this filter is to destroy the bad odour from the RO purified water.

TDS Controller
As explained earlier, the RO purified water has low levels of TDS. In the process, the water loses essential salts like calcium, potassium, and magnesium, among others.

The TDS controller replenishes these salts and balances the pH level of water. We have discussed that pure water is tasteless and odourless. Hence, the TDS controller serves to balance the pH levels and make the water tasty and healthy to drink.

 The mineraliser performs a similar function as the TDS controller. It supplements the mineral content lost during the RO purification. The mineraliser is a better option than the TDS controller, as it replenishes the specific minerals.

Comparison between different water purification systems

We have seen the different types of water purification systems in the above paragraphs. Each of these systems has its advantages and disadvantages. This comparison will highlight the difference between these systems and clear the concept.

Reverse Osmosis vs Ultra-Violet (RO vs UV)

RO purification process ensures the elimination of TDS and other contaminants like mercury, arsenic, and lead from the source water.

The UV water purification process cannot remove these toxic chemicals. At the same time RO cannot destroy all viruses and bacteria present in the water, whereas the UV process can eliminate all germs and microorganisms.

Therefore, the UV water purifier is best when the water source has TDS levels less than 500. If the TDS level is more than 500, nothing can be better than the RO water purification.

Reverse Osmosis vs Ultra-Filtration (RO vs UF)

Reverse Osmosis is a specialised filtration procedure that uses scientific principles to purify water. Ultra-filtration is an advanced type of sediment filter, but with smaller pores. It is different from Reverse Osmosis.

Ultra-filtration can eliminate minute impurities but cannot deal with TDS and other contaminants like lead, mercury, and arsenic.

You need an advanced process like RO to cater to such tasks. RO process is not required when the TDS levels are less than 500. However, UF works excellently in combination with RO.

Ultra-Violet vs Ultra-Filtration (UV vs UF)

Ultra-filtration process does not deal with viruses and bacteria, whereas Ultra-violet process eliminates them completely.

However, the UV process cannot deal with sedimentary impurities. Therefore, when the water source has turbidity levels. The UV filtration process is of no use. You need either UF or RO to deal with such water.

Thus, the ideal water purifier is one that has a combination of all the three. Most of the top water purifiers in India come with RO + UV + UF.


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