“We want you to spend your money on the perfect water purifier you need.”

Best Buying Guide for a new Water Purifier in India 2020

If you don’t know anything about the water purifier, don’t worry, just leave it on us. We will take care of it, just like water purifiers that take care of life-threatening water-borne diseases and the weird taste of chlorine, which may have ruined your Tea or coffee!

We will first start with the different types of impurities found in drinking water. Then we will discuss the different types of water purification technologies, as it is our main aim to guide you toward the best water purifier you need for your home or office.

You can also check the Top 10 Best Water Purifiers in India & 6 Ways to use wastewater from RO water Purifier here.

Impurities Found in Drinking Water

Impurities found in the drinking water depend on the source of water; the most common water sources are:

  • Municipal Corporation Supply
  • Rivers
  • Lake/Ponds
  • Borewell/Groundwater

We can say the fundamental sources of water are rivers. Initially, the water is pure, as these rivers gather salts and minerals from the rocks and sand when the water passes through the filed.

Salts contain potassium, chlorine, magnesium, sodium, phosphates, nitrates, bicarbonates, chlorides, and sulfates, and together they form a major component. We can refer to this component as TDS (Total Dissolved Salt).

But, when the rivers get in touch with human wastes like sewage and other wastes such as plastic, Agricultural Pollution, Oil Pollution, Radioactive Substances, and harmful industrial chemicals such as arsenic, lead, iron, and mercury. etc., they get polluted. If we drink that water without purifying it, all these impurities will find their way into our body and cause harmful water-borne diseases like cholera, dysentery, etc. Therefore, we can’t deny the need to purify the water before consuming it. 

The below table describes the most common types of impurities in water:

Un-dissolved solids such as sand and mudRiver, borewell or piped water where pipes are damagedMuddy or turbid appearance
Dissolved inorganic salts like Sodium & PotassiumBorewells and seawaterSalty or brackish taste
Dissolved inorganic compounds like Calcium & MagnesiumBorewells and river waterHardness and scale formation
Organic compoundsLakes and pondsFoul smell or bad odor
Decontaminants like ChlorineMunicipal piped water supplyBitter taste
Biological impurities like bacteria & virusesPiped water where pipes are damaged, water tankersBiological contamination, waterborne diseases

Identify the Water Type – Soft or Hard Water

You may have read about the hard water and soft water in class 9, in which if the water foam lather with soap, then the water is known as soft water; otherwise, we can say it is hard water. It is because the soft water has a low level of TDS value ranging between 150-300 ppm, and the hard water has a high level of TDS value higher than 500 ppm.

Hard water vs Soft water

1 ppm (Parts Per Million) = 1 mg/L  

The high percentages of dissolved solids like calcium, magnesium, heavy metals, fluorides, and arsenic make water hard, unhealthy for us, and cause life-threatening water-borne disease. 

On the other hand, water sourced from rivers, rainwater harvesting systems, lakes, and municipality storage is generally termed as soft water. This water is not as dangerous as hard water, as the TDS level is below 300 ppm; therefore, you should go for a Non-RO water purifier, as it does not waste any water at all. Suppose your water is contaminated with a high concentration of heavy metals and harmful chemicals even at a low level of TDS (Below 300 ppm). In that case, you should go for a RO water purifier.

NOTE:  Non-RO water purifier for a low level of TDS and absence of heavy metals and harmful chemicals in the water.”

Types of Water Purifiers

NOTE: The Images below are not Sponsored by any brand, we are using them to maintain the quality and simplicity of the article.

Non-Electrical With Storage

KENT Gold 20-Litres UF technology based Gravity Water Purifier, Blue

These water purifiers purify the water through sediment and activated carbon filters and have storage tanks to store the purified water. Highly reliable in the areas where electricity is a big concern.

Non-Electrical Without Storage

Eureka Forbes Aquasure Tap Water Purifier.

These water purifiers have a fixed water tap without a storage tank. They have a candle-shaped resin filter that needs to be replaced once a month. They also have UF and Activated Carbon filters, which run without electricity. These water purifiers are made up of food-grade plastic, and they are lightweight and small so that we can carry them anywhere.

Electrical With Storage

KENT Superb Star RO+UV+UF+TDS Controller

These water purifiers use sediment filters and activated water filters with UV or RO purification systems, which require electricity to run. They have a food-grade plastic storage tank to store the purified water.

Electrical Without Storage

Pureness Acqualite Without Storage UV+UF Water Purifier in Food Grade Body

Electrical units are also available without a storage tank, and the filtration quality is the same as those with storage. 

Types of Water Purifiers: Based On Purifying


Reverse Osmosis (RO) Purifiers

Let’s first understand the Osmosis; it is a process in which the water naturally flows from low solute concentration (low TDS level) to high solute concentration (high TDS level) through a membrane.


The membrane consists of tiny holes (about 0.0001 microns), the water molecules are smaller than the tiny holes, which allows water to pass through them, and the minor dissolved impurities and bacteria get trapped.

Now, let’s understand Reverse Osmosis (RO), it is the opposite process of Osmosis, in which the water is pressurized with the help of a water pump to reverse the natural flow of water, means now the water will flow from high solute concentration (high TDS level) to low solute concentration (low TDS level) through a semi-permeable membrane and leave the dissolved solids and other impurities behind.

Reverse Osmosis

The dissolved solids, impurities, and some input water left behind in the RO process refer to as RO wastewater and get discharged through a separate outlet.

Drawbacks of RO technology:

Waste water

We can say for every 1-liter of pure water it produces; the purifier wastes 2-litres of water. The wastage also depends on the quality of the input water, higher the TDS of water, higher will be the wastage. 

In the era of the global water crisis, it is important for you to buy the RO water purifier only when you need it. Otherwise, you can go for a Non-RO water purifier that doesn’t waste any water at all. It would be best if you choose a RO water purifier that offers a higher rate of water recovery.

It is always an excellent decision to reuse the RO wastewater, and not throwing it off. “You can also check the 7 Ways to Re-Use RO waster water.”

Required Electricity

RO technology doesn’t work in the absence of electricity as a purifier uses a water pump to apply external pressure to make the natural Osmosis process reverse.

Ultrafiltration (UF) purifiers

Ultrafiltration process

It also uses a semi-permeable membrane to purify water. But here is a catch, the holes in the membrane are more massive (about 0.01 micros) as compared to the membrane used by RO (about 0.0001 microns).

UF can work without electricity as the membrane has larger holes. Therefore water can pass the membrane naturally, without using any water pump, results in no-wasting of water at all. But UF purifiers are not suitable for the water of high TDS level as it can only remove undissolved solids because of the large hole in the membrane. Only the RO Technology can remove the dissolved impurities.

Ultraviolet (UV) purifiers

Ultraviolet purification porcess

UV purification technology uses ultraviolet rays to purify the water. It throws the high-intensity UV rays on the water and kills or deactivates the disease-causing bacteria and viruses. 

However, it cannot remove any impurities and chemicals from water. That’s why an external sediment pre-filter is used to remove undissolved impurities and activated carbon filters to remove Chlorine and some dissolved impurities. Therefore this UV purification technology is recommended when the TDS level is low. If the water contains bacteria at low TDS, then you should go with the UF+UV water purifier.

Tap/Faucet Mounted Filters or Gravity Based Purifiers

These purifiers are suitable in the area where the TDS level is low, and water is not highly contaminated.

Tap/Faucet Mounted Filters/purifiers cab be fitted on taps as they are easy to use. They are the combination of sediment or sediment + activated carbon filter. These types of purifiers can remove large and undissolved impurities and some of the chemicals and micro-organisms.

Gravity-based storage purifiers are the advanced version of tap/faucet filters. These purifiers offer an in-built storage tank to store the input (impure) water. Most of the Gravity based water purifiers have two separate storage tanks for input and output water.

Which Water Purifier Is The Best For Me?

The below table suggests you the best water purifier you need.

Below 500 ppmNoNoGravity-Based Purifiers
Below 500 ppmNoYesUV
Below 500 ppmYesNoUF
Below 500 ppmYesYesUF or UF+UV
Over 500 ppmNoNoRO
Over 500 ppmNoYesRO + UV
Over 500 ppmYesNoRO+UF or RO+UV+UF
Over 500 ppmYesYesRO+UV+UF

Main Components of RO Water Purifier

The sediment filter

Sediment Filter

This filter is optional and fitted outside the machine, but this can enhance the RO membrane’s life. This filter removes the visible suspended particles and more significant impurities; thus, larger impurities do not enter the machine. In the case of clear water or the water supplied by the municipalities, you don’t need this filter.

Pre-activated carbon filters

Pre-activated carbon filter

The pre-activated carbon filter removes organic and the other volatile compounds from the water, which are responsible for the bad odor of water.

Reverse Osmosis mechanism

Reverse Osmosis machanism

The next stage of filtration is RO filtration. In this, you need to use a pump to push the water through the RO membrane as the water does not suppose to move from a higher solute concentration to lower solute concentration when passing through a semi-permeable membrane in the ordinary course. This is the principle of Reverse Osmosis.

The RO membrane removes all kinds of impurities in the water, such as TDS, pesticide residue, heavy metal impurities like mercury, lead, arsenic, and biological impurities like bacteria, viruses, and micro-organisms.

After the RO process, the water is separated into two parts, pure and impure. The impure part goes down the drain and the pure and filtered water that passes through the UV chamber for the next stage of filtration.

Ultraviolet protection

The pure water obtained through RO filtration still contains many bacteria and viruses as the RO membrane cannot filter out impurities with a molecular weight of less than 20. It cannot eliminate monovalent ions like sodium, etc. The UV purification does not use chemicals like chlorine and also does not add any chemical taste and odor. Also, the ultraviolet radiation kills all micro-organisms and bacteria, results in making the water 100% safe to drink.


Ultrafiltration membrane contains microscopic pores that trap any impurities that might have escaped elimination in the RO process.

Post-activated Carbon filter

This filter removes the volatile organic compounds, which cause bad odor in pure water. This process improves the taste of water.

The TDS Controller

TDS Controller

The water that comes out of the RO water purifier is pure and healthy. But, the RO mechanism eliminates almost 90% of the TDS from the water, including excellent and healthy salts like calcium and magnesium, etc. These salts and minerals are necessary for the overall growth of the body. Therefore, the TDS controller plays a significant role by separating the input water into two parts, A and B. 

Part A goes through the RO membrane. In contrast, Part B passes through the UV / UF membrane that does not remove the TDS but kills the micro-organisms.

The TDS controller then selectively mixes this water with the RO purified water, results in increasing the TDS levels and increasing the water’s pH value.

Storage Tank

Water purifiers come with the storage capacity varying from 7 liters to 12 liters. In case you have a bigger family or long power cuts in your area, you should go for a water purifier with a bigger storage tank. 

A storage tank allows you to access purified water at any time. A water purifier with a storage capacity of 7-liters or higher is suitable for most Indian households.

Indicators & Alerts

Indicators and Alerts

They also play a major role in any water purifier. They are must-have, as they alert you to change filter and UV fail, and with the help of these alerts, we can get them repaired on time. 

If the water purifier doesn’t have any Alerts & Indicators then, it would be very difficult to know what’s happing with the purifier, like wheater it is purifying or not, and the tank is full or empty, etc.

Final Thoughts

We hope you enjoyed reading this informative and useful content. If you are looking for a RO water purifier, check out the best water purifiers

We don’t recommend you go for RO water purifiers if the TDS level is below 300 ppm and does not contain any heavy metals and harmful chemicals. If you need RO water purifiers, then you must go for the product, which offers a higher recovery rate of purified water. 

Still, if you have any doubts or thoughts, please share them in the comment section below. We are out here to help you out.


Please enter your comment!
Please enter your name here