Best Water Purifier Buying Guide: How to choose a water purifier in India?

Amita Gupta

Are you looking for a water purifier for your home or office? Do you feel confused looking at all the options available out there? Then you have arrived at the right place.

Access to fresh and clean water is a basic right of every human being. But there is a scarcity of pure and drinkable water in many parts of India.

People have to rely on water containing various water contaminants like heavy metals, pesticides, herbicides, disease-causing bacteria, and germs, making the water unfit for human consumption. This is why water purifiers are one of the essential household appliances.

Water purifiers use different purifying technologies. They have different filters to remove different types of impurities. One also needs to consider factors like the storage tank’s capacity,  water pressure, maintenance cost, etc.

Without any help, it might be challenging to choose the right water purifier. To make your job easier, we provide you with a water purifier buying guide, where we will discuss the factors that you need to consider while buying a water purifier. So, keep reading.

What is the source of your drinking water?

Water Purifier Buying Guide

To know how to choose a water purifier, you need to find your drinking water source. The quality of water, level of contaminants found, and water taste all depend on the water source.

In India, the most common drinking water sources are municipal water, underground water, harvested rainwater, ponds, lakes, river water, water tankers, etc.

What are the commonly found impurities in your water source?

Let’s look at some of the most common types of contaminants found in different drinking water sources. Later we will talk about what water purifier is suitable for what water quality.

Water SourceEffects on waterContaminants Found
Municipality supplied piped waterSmells like chemicalsDisinfectants  like chlorine, chlorine dioxide, etc
River water, lake waterCloudy or muddy appearanceSand, mud, and some undissolved solids
Seawater, borewellBrackish or salty tasteHigh levels of dissolved sodium and potassium salts
Borewells and water tankersWater hardness and scaling formationHigh levels of dissolved calcium, magnesium, and irons
Ponds, lakes, harvested rainwaterFoul smellBacteria, virus, protozoa, algae, cyst, etc
Old water tanks with damaged pipesTurbid appearance, frequent waterborne diseasesBiological contaminants like bacteria, virus, protozoa, etc

Besides TDS (Total Dissolved Salts) and microbiological impurities- bacteria, protozoa, cyst- a few other contaminants are also found in common drinking water sources: pharmaceutical residues, microplastics, dissolved drugs, etc. Contaminants like lead, arsenic, fluoride, nitrates are limited to certain parts of India.

To conclude, there is no one-size-fits-all water purifier available anywhere. It’s crucial to determine the nature and quality of water and then decide on the water purifiers.

What are water TDS Levels? How much TDS is considered safe in drinking water?

Total Dissolved Solids or TDS is a term that represents the concentration of dissolved inorganic salts and a small number of organic substances present in water. It is measured in parts per million (ppm) or milligram/liter (mg/L ).

1 mg/L = 1 ppm

The most common inorganic salts present in water include calcium, magnesium, phosphate, sodium, potassium, other cations, and anions like carbonates, bicarbonates, chlorides, sulfate, and nitrates.

According to WHO ( World Health Organization), TDS levels between 50-120 ppm (mg/L) are the most suitable limit for drinking water. However, according to India’s standards for drinking water, up to 500 ppm TDS is permissible.

TDS LevelsQuality of Drinking Water
Below 50 ppmUnacceptable due to very low levels of TDS
Below 300 ppmExcellent
300 to 600 ppmGood
600 to 900 ppmAverage
900 to 1200 ppmPoor
Above 1200 ppmNot acceptable as drinking water

Is it soft water or hard water?

Water can be classified as soft or hard, depending on the TDS levels. Usually, a TDS value between 150 to 300 ppm is considered soft water, and a TDS value higher than 500 ppm is called hard water or polluted water.

Hard Water Sources

Does the water supply in your area come from underground sources or drawn from deep wells? Then most likely, the water is hard water. It means the water supplied in your area has a higher concentration of heavy metals.

The TDS value of underground water can vary from 200 to 3000 ppm. TDS levels higher than 1000 ppm become very unpalatable, according to WHO. It can be toxic. Plus, there might be a chance of the water containing lethal chemicals like lead, arsenic, and fluoride.

You need a water purifier that can get rid of these heavy metals along with the biological contaminants.

Soft Water Sources

If the water in your area is municipality tap water or sourced from rivers, lakes, or harvested rainwater, you have a soft water supply. It usually has a TDS value below 300 ppm which is considered ideal for drinking water.

Soft water might not be as dangerous as hard water, but it might contain other contaminants such as viruses, bacteria, protozoa, cysts, etc.

Since you have low TDS levels, you need a water filter that can stop the microorganisms from growing inside the water.

What are the different water purifying methods?

There are various technologies used in water purifiers:

  • RO (Reverse Osmosis)
  • UF ( Ultrafiltration)
  • UV ( Ultraviolet)
  • RO+UV ( Reverse Osmosis + UltraViolet)
  • Gravity Based water purifiers

Some manufacturers combine two or more filtering technologies to suit different types of water quality.

Still, there is no ‘ultimate best’ water purifier. As mentioned earlier, what water purifier works the best for you depends on the quality of water supplied in your home.

RO ( Reverse Osmosis) Water Purifiers

Reverse Osmosis is the opposite method of natural osmosis. It passes water molecules from higher TDS concentration to lower TDS concentration using a high-pressure water pump. It pushes water molecules through the RO membrane with a pore size of 0.0001 microns approx.

As the water with high TDS levels passes through the RO membrane, it leaves all the dissolved solids and other impurities inside the chamber. Later, this rejected water with dissolved solids and impurities is discharged through a separate outlet called RO wastage.

Along with the RO membrane, these purifiers are also equipped with some other filtration techniques. There can be a total of 3 to 4 stages of filtration in an RO water purifier which are:

  • Sediment Filter: It removes all the suspended impurities from water and increases the life of the RO membrane.
  • Activated Charcoal Filter: Removes odor from chlorine and other impurities also absorbs pigments.
  • TDS Controller: RO purifiers remove essential minerals from drinking water, including calcium, magnesium, and iron. So, many RO purifiers come with a TDS controller, which puts some essential minerals back into the water to maintain a healthy TDS level.
  • Post Carbon filter: Enhances the taste of drinking water.

Where do they fit in?

RO water purifiers should be used to purify water that has TDS levels over 500 ppm.

Pros of RO Water Purifiers:

  • Effectively works in high TDS levels
  • Removes harmful metals and chemicals like fluoride, arsenic, lead, etc
  • Reduces water hardness caused by calcium and magnesium salts

Cons of RO water purifiers:

  • Wastes water
  • Might eliminate essential nutrients and minerals from water

UV Water Purifiers

UV water filters use ultraviolet rays to kill and deactivate the virus and bacterial activities. They have ultraviolet lamps inside the filter, which emit strong UV rays to kill or neutralize the growth of disease-causing microorganisms.

However, UV water purifiers cannot remove dissolved salts or chemicals from water. Nowadays, most UV water filters come with an additional pre-filter to eliminate TDS and other impurities from water.

Where do they fit in?

UV water purifiers are the best water purifiers for water sources that contain biological impurities and have TDS levels below 500 ppm.

Pros of UV water Filters:

  • UV water filters use no chemicals
  • It’s a faster purification process
  • Stops virus and bacterial growth
  • Relatively low maintenance cost

Cons of UV water purifiers:

  • Cannot remove heavy metals and chemicals
  • Slightly expensive

UF ( Ultrafiltration) Water filters or Gravity based water filters

Similar to RO, UF water filters also purify water using a semi-permeable membrane. But there are significant differences between them. The membrane used in the UF water purification system has much larger pores ( 1.01 microns approx) compared to the RO membrane has even smaller pores ( 0.0001 microns).

As a result, UF water filters can only remove larger un-dissolved substances and organic impurities like viruses and bacteria. They can work without electricity because of their much larger pores which lets water molecules pass using the gravitational force while leaving larger impurities.

Where do they fit in?

UF Water purifiers cannot remove TDS and harmful metals. So, they are recommended for areas that have low TDS levels. The advantage of using Ultarfilation water filters is that they don’t hold back any water. Hence, there is no water wastage like RO.

If you have lower TDS levels in the water but it appears muddy and contains biological contaminants, then UF+UV water filters are the best water purifiers to use.

Pros of UF water filters:

  • Effectively removes mud and sand
  • Removes virus and bacteria
  • Works without electricity
  • Doesn’t use any chemicals

Cons of UF water filters:

  • Cannot work in TDS levels
  • Cannot remove heavy metals and chemicals

RO+UV water filters

Some top-of-the-line manufacturers provide their water purifiers with both RO and UV ray filtration. These can remove high levels of TDS and stop biological growth of viruses and bacteria.

Tap or Faucet Mounted Water Filters

They are the simplest forms of water filters that provide basic water filtration. They usually have a sediment filter or a sediment-activated carbon filter to remove larger un-dissolved impurities such as sand and mud, and remove odour and some chemicals and microbes. They can be directly fitted to taps and faucets.

Which type of water purifier do I need?

Nowadays, there are too many kids of water purifiers and purifying technologies like UV, UF, RO, and their mixtures. Trying to compete with other brands, manufacturers advertise advanced water purification technologies, but most use a different combination of these three primary filtration techniques: RO, UV, and UF.

To choose the right water purifier you need, you know the TDS levels in your area. If it’s below 500 ppm ( 500 mg/L), you don’t need an RO water purifier. Why? We will discuss the reasons further in detail below.

If it’s over 500 ppm, look for an RO water purifier. Closely notice the water if it has a cloudy appearance, a foul smell, or a brackish taste. We have made a table listing all the parameters and qualities of water and the most suitable type of water purifier.

TDS levels (ppm or mg/L)Water appearanceBiological ImpuritiesThe water purifier you should Use
Below 500ClearNo biological impuritiesUF
Below 500ClearBiological impurities presentUV
Below 500MuddyNo biological impurities UF
Below 500Muddybiological impurities presentUV+ UF or UF
Over 500ClearNo biological impurities RO
Over 500ClearBiological impurities presentRO+UV
Over 500MuddyNo biological impuritiesRO+ UV or RO+UV+ UF
Over 500MuddyBiological impurities presentRO+UV+ UF

To sum it up:

  • The UF water purifier will work just fine for soft water like municipal water, which is already sterilized and has low TDS levels.
  • For soft water with high levels of biological impurities, choose a UF+UV water filter.
  • Hard water without toxic metals and biological contaminants will need an RO water purifier.
  • Hard water with high levels of biological impurities will require RO+UV or RO+UV+UF water filters.
  • UF filters can only remove suspended larger contaminants. They are best to use in combination with other purification methods such as UF+UV, as they don’t kill germs and might leave some viruses and bacterias left in the water.
  • To eliminate the smell of chlorine from water, make sure your water filter comes with an activated carbon filter.

Do not use RO water purifier if…

RO water filters are widely popular in India. So popular that the term ‘RO’ is synonymous with water purifiers.  Due to this, most people buy RO water purifiers by default without considering the factors like the source of their drinking water, TDS levels, and impurities found.

Remember that RO water purifiers are required only when the water has high levels of TDS. Calcium and magnesium are two minerals that mainly create high TDS levels in the water. TDS in drinking water doesn’t necessarily cause any health risk. But it alters the taste of water, causing water hardness, brackish water, and scaling formation.

TDS According to The Bureau of Indian Standards (BIS), TDS levels up to 500 ppm in water are ideal for drinking. But certain compounds like copper, lead, pesticides, nitrogen, and drugs can lead to health hazards when dissolved in drinking water.

If you receive water from municipal water, filtered river water, harvested and filtered rainwater, know that it already has very low  TDS  levels ( generally below 200 ppm). And if you know the TDS level is below 500 ppm, there’s no need to use an RO water filter because the RO purifier will further reduce TDS concentration in your drinking water.

Such low TDS levels mean the water purifier filters out good minerals and nutrients like calcium, magnesium, and iron required by our body to maintain good health.

Also, RO purifiers have a much higher replacement cost. So, why bear the extra expenses? If you buy a RO water purifier, make sure it has a TDS controller which puts some of the essential minerals back into the water to maintain a healthy TDS level.

How much water do I need to store?

After determining what type of water purifier you will require for your water condition, you need to figure out how much water you need to store?

An average adult consumes 2 to 4 liters of water a day, based on which you can come up with an idea of how much water your filter needs to filter and store. You also need to consider the filtration capacity.

Family SizeDaily water consumption
1 to 2 members4 to 5 liters
3 to 4 members6 to 8 liters
5 to 8 members10 liters or more

 If you have a large family and the water purifier is slow at purifying water, it might take you hours to fill the bottles.

Electric vs. non-electric water purifiers

If frequent power cuts are common in your area? Then this might be a big thing to consider.

Depending on the use of electricity, there can be two types of water purifiers: Electric and non-electric

  • Electric water purifiers: RO water purifiers, UV water purifiers, RO+ UV water purifiers
  • Non- electric water purifiers: UF or Ultrafiltration, Gravity-based water purifiers, and activated carbon filters.

RO filters cannot work without electricity. They make use of an electrical pump to push the water through the membrane. Without electricity, there’s no use of RO water purifiers. Similarly, UV water filters use UV lamps which also require electricity to work.

If you must choose RO or UV water filters, make sure it has sufficient storage capacity for your family.

Adequate Water Pressure

The water pressure in your area is another important factor to consider while choosing a water purifier for your home or office. RO water purifiers cannot work under low water pressure. They need around 10 to 40 psi of water pressure to work efficiently.

This is why manufacturers recommend using a pressure booster pump along with the RO water purifier. It is attached to the system to increase the water pressure, but it can cost you several thousand more. If you have lower TDS levels and low water pressure, you should better opt for UF or UV water filters.

Should I go for stainless steel water storage tanks?

Most water purifiers have storage tanks made of food-grade durable plastic. But some manufacturers are providing stainless steel storage tanks.

It is claimed that purified water stored in plastic storage can again grow bacteria and germs if left unused for a long time. Stainless steel storage tanks are claimed to offer a more extended protection period against the reappearance of microorganisms compared to plastic tanks. This is why some brands provide their purifiers with UV lamps inside the storage tank.

Water purifiers with stainless steel storage tanks are costlier compared to food-grade plastics. Some experts have denied the fact that germs can reappear in the stored water. According to the, stainless steel tanks are unnecessary, as there’s rarely any chance of bacteria emerging again in purified water.

Best Water purifier brands in India

Too many brands sell water purifiers in India. But to name a best, we must include the followings:

Brands with best water purifier in India Country of Origin
Eureka ForbesIndia
Blue StarIndia

Unlike smartphones, water purifiers cannot be upgraded once in a year or two. It’s going to be with you for at least ten years. So, it will come with a similar price tag. We recommend you to buy from a reputable brand.

Considering a reliable brand, good quality filters, expect the price of a water filter to be around 7000 INR to 8000 INR. The budget can increase if you opt for RO+UV water purifiers.

Other things to consider


Brands with the best water purifiers in India offer a 1-year warranty on the product plus, 1-year warranty on the RO/ UF membrane. UV lamps, sediment filters, carbon filters, and post-carbon filters usually come with a 6-months of warranty.

Maintenance cost

Like every household appliance, water purifiers also need some maintenance. The maintenance cost includes changing filters, cleaning, and general servicing of the appliance. Gravity-based purifiers are low-cost maintenance compared to RO and RO+UV purifiers, a lot more costly in maintenance and repair costs. A good water purifier has around 2000 INR annual maintenance cost, but it can go up to 5000 depending on the brand, technology, and required service.

After-sales services

After-sales services for a water purifier is a thing to consider. Make sure your area has a service network of the brand that you choose. Check the brand’s official webpage and social media page to ensure quality service. Also, check how fast the customer representatives visit home after making a service request. Read online reviews of customers and your friends and families if you need.

AMC plans

Some high-end brands have Annual Maintenance Contract or AMC plans which charge a minimal amount and offer free services for 1 to 3 years. It includes changing filters every 6-months to 1 year, labour costs, and repair costs. AMC plans can be cheaper in the long run.

Filter replacement cost

RO filters are more expensive than any other type. The cost of replacing RO filters and other filters varies from brand to brand. So, find out how much the brand cost to give a replacement of the filters.

Availability of parts

Very often, a brand decides to discontinue manufacturing a model from their range. As a result, the spare parts also become no longer available. So, you are left with two options, using substandard parts or buying a new water purifier. To avoid both, make sure you buy a newer model from a reputable brand with the best reviews from current customers.


How do I know the water filters need a replacement?

Usually, filters need a replacement every 6 months to 1 year. Some water purifiers come with a filter replacement alert. If your water filter doesn’t come with a filter replacement alarm, any of the following signs might indicate dysfunctional filters:
● The water has a foul odor or tastes bad. If it tastes more salty or brackish and appears to be cloudy, it’s time for a filter replacement.
● Decreased pressure in the fauces around the house can also indicate filters are clogged up and need replacement.
● Noise from the water filter faucet can be another sign of filter replacement.

How effective are tap water filters?

Tap water filters usually have a sediment filter. To remove suspended particles, microfilters to remove dissolved hard water salts and a carbon filter to remove foul smell and chlorine. They are pretty effective water purifiers for soft water. They are mainly used to filter water used in the kitchen and bathrooms because they cannot remove microbiological contaminants such as germs, viruses, and bacterias.

How does the activated charcoal filter work?

Activated charcoal is highly absorbent. It purifies the water using the process of absorption. It has large pores around its surfaces, which absorb chlorine and unpleasant smell and filter out fresh and odourless water. They are not able to remove heavy salts, metals, and microorganisms.

Which water filter removes viruses from water?

RO water purifiers with 0.0001-micron size filters are able to remove a few viruses but not all. Generally, speaking water purifiers are designed to remove bacteria, protozoa, and cysts but not viruses. UV water filters can neutralize the viruses but cannot remove them from water.

Which is better, RO or UV?

RO water filters are the best for water with high TDS levels of water heavily contaminated with toxic metals such as arsenic, fluoride, lead, etc. However, using RO in areas with low TDS levels further reduces the amount of essential minerals like calcium and magnesium, essential for maintaining a healthy body.
UV filters use ultraviolet rays or UV rays to kill bacteria and viruses in water. They are the best for water that contains low levels of TDS.

Is RO water bad for health?

RO or Reverse Osmosis water purifiers are very effective at cleaning water. But along with removing dissolved salts, they also remove essential minerals from the water like calcium and magnesium, which are very important for a healthy body. Long-term consumption of water devoid of minerals is unhealthy.
Some manufacturers provide RO purifiers with TDS controllers to solve this problem, which adds the minerals back into the water and maintains a healthy TDS level. Hence, an RO water purifier with a TDS controller is not bad for health.

Final Word

To sum it up, how you will choose your water purifier solely depends on the water quality supplied to your home. If you have read the entire article, you should be well aware that RO purifiers are only required for removing high TDS levels, which is generally over 500 ppm.

UV+UF water purifiers are an excellent choice for areas with low TDS levels. The easiest way to measure the water TDS levels at home is by using a  digital TDS measuring device. But you can follow our guidelines to have an overall idea of the TDS levels around your area. If the water in your area is highly polluted, then RO is the best choice to go for.

Remember that water purifiers are not like smartphones that you can change after a year. It’s a long-term investment, so choose a brand with at least 1-year of warranty on the product and 6-months of warranty on the filters. And don’t forget to replace the filters from time to time.

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