Water purifier buyer’s guide for selecting best purifier

hozone water purifier

We humans can live without foods but not without water.

Perhaps the time when this phrase was coined, people were lucky to have water source which were pure and drinkable. With the use of chemicals and industrialization we are now having scarcity of pure drinking water.

You can’t trust water bodies and water supplies blindly when it comes to health of your family. Thanks to the availability of varieties of water purifier in the market, which ensures every drop of water that you get is pure and free from any contamination.

A good quality water purifier

  • Keep you and your family Safe from any possible life threatening waterborne diseases that may be caused by contaminated water

  • Removes the taste of water soluble chemicals like chlorine, calcium carbonate and gives you genuine taste of water

There are various terminologies that you will encounter while looking for any specific product as a part of its feature. Let’s see those keywords in details; this will help you in deciding which factor is essential for your need.

1. TDS (Total Dissolve Solid)

As per WHO, Total dissolved solids (TDS) is the term used to describe the inorganic salts and small amounts of organic matter present in solution in water.

Example of some of the inorganic salts which are found in water are calcium, magnesium, potassium and sodium, which are all cations, and carbonates, nitrates, bicarbonates, chlorides and sulfates, which are all anions. 

Concentrations of TDS from natural sources have been found to vary from less than 30 mg/litre to as much as 6000 mg/litre, depending on the solubility of minerals in different geological regions.

India follows BIS Standard , which says that the maximum desirable TDS is 500 mg/L and the maximum permissible level in the absence of a better source of water is 2000 mg/L.

There is no any laboratory or testing proof that put any water with low TDS superior to high TDS unless that value is more than 500 mg/L. As far as it’s below BIS standard it’s healthy and acceptable from TDS prospective.

If you are receiving municipal water at your home it will be always under 500 mg/L.

You can use digital TDS meter to check the TDS level of water at your home. These are available online and you can choose among these

In general:-

  • TDS is less than 200- go for UV, UF Water Purifier.
  • TDS is greater than 2000- Domestic Water Purifier cannot be used. Buy a water softening solution.

2. How does TDS affect selection of water purifier?

There are three major type of water purifier you would be seeing around RO, UV and UF purifier. You only need RO purifier if water at your house is having TDS value beyond BIS standard.

If your house water is having TDS value less than 500 mg/L, straightway you can go for UF or UV purifier.

3 .What is Sediment filter and a carbon filter?

Sediment is a generic term for any unwanted particles or component or anything in the water that’s not liquid. A sediment filter make use of spun polypropylene or other material to captures and removes sediment or particulate.

carbon filters in water purifier hozone

Most basic water filtering need is to remove sediment from water. They are like nets that catch and hold particles that are too large to pass through the holes in their surface. 

It is integral component of purifier like RO and UV that helps in smoothening of further filtration process.

A sediment filter does not remove dissolved solids, microbes or particles solution and attached to the water molecule.

Activated carbon water filter removes chlorine and most of the pesticides and heavy metal organic chemicals in the water and thus improves the taste of water and also removes bad smells in water.

Activated carbon filters are extremely porous material that attracts and holds harmful chemicals. With the repeated usage this gets depleted and required change periodically.

  • Activated Carbon water filter purifier does not remove microbes and dissolved inorganic chemicals like Nitrates, Fluorides, Arsenic and does not remove hardness in water.

  • This carbon filter can become breeding ground for micro organism if the filter is not under use over a period of time.

If there is chance that your water would be infected with microbes then it is better to use bleaching powder before to disinfect water and then use this filter. Carbon filter will anyway remove the chlorine smell along with other chemicals and pesticides.

4. What is Filtration stage in water filter?

Every reverse osmosis water system contains a sediment filter and a carbon filter in addition to the RO membrane. The filters are called either pre-filters or post-filters depending on whether water passes through them before or after it goes through the membrane.

The number of pre-filters or post-filters added to an RO system determines the number of stages. 4 stage filtration system is sufficient in most cases.

water purification stage hozone
Water purification stage

If you’re on well water or an area with high levels of sediment, you may want to consider a system that has extra pre-filtration (5 stages).

The RO membrane does most of the work removing dissolved solids, but additional pre-filters and post filters can polish, re-mineralize, and provide additional chlorine and sediment removal. Eventually, the membrane wears out, but pre-filters give an initial pass through filter media to help extend the life of the membrane.

5. What is GPD Rating value?

RO systems are rated on how much water they can produce per day (gallons per day or GPD). Whatever the GPD rating of a purifier is the actual flow rate (in GPD) of any reverse osmosis system depends on your home water pressure and temperature. Expect actual GPD (gallons per day) production rate of 50% to 75% of system GPD rating.

If somewhere 50 GPD rating is mentioned than that’s the speed with which RO system produces drinking water per hour (with normal water pressure of about 60 psi). For a 50 GPD rating the flow rate may be 35 or 30 GPD practically.

6. How does Permeate Pump work?

Permeate pumps help RO systems save water. A permeate pump increases a system’s efficiency by 85% and without this pump your RO system will waste significantly more water.

RO systems are not the most efficient in term of speed. Since RO systems make water slowly, they use a storage tank to hold clean water until you need it. As water fills the tank, air compresses and creates pressure. These RO storage tanks use air pressure to push the water out.

A permeate pump requires no electricity to operate. Instead, it uses the hydraulic energy that would otherwise be wasted to prevent more water from going to the drain when the RO tank nears full.

7. What is use of Mineralizer or Mineral Cartridge?

RO filters removes most of minerals from water including some which are essential and give taste to water. Now since minerals are essential so you have two option here

Either you say no to minerals that we take from water and depend on minerals from food only.


Use TDS controller to control the mineral presence in the water thereby compromising on RO purified water quality which is not much recommended.


Once water is RO purified use the mechanism to add minerals in RO purified water. For this Mineralizer or Mineral cartridge is used.

Mineralizer hozone water putifier

Mineral cartridge consists of essential minerals like calcium and magnesium in proper proportionate. Water passes from one end of mineral cartridge to another end because of which mineral composition and pH value of purified water is maintained around ideal value.

  • Mineral cartridge is essentially useful for RO purifier only.

8. Water Purifier type

There are mainly three type of water purifier based on technology which is used to purify the water.

  • Reverse Osmosis water purifier (RO)
  • Ultra violet purifier (UV)
  • Ultra Filtration purifier (UF)

Reverse Osmosis (RO) Ultra Violet (UV) Ultra Filtration (UF)
Filtration process Reverse osmosis (RO) is a water purification technology that uses a partially permeable membrane to remove ions, unwanted molecules and larger particles from drinking water.   The Ultraviolet (UV) Purifier uses a high dose of ultra violet light energy at a wave length of 254 nanometers to kill the Bacteria, and other microorganism present in the water.   Ultra filtration (UF) process pushes water through a semi permeable membrane which removes any contaminants like bacteria, viruses, and parasites.
Features > Wastes a lot of water

> Requires electricity for functionality

> High cost and high maintenance

> Removes most of the minerals and salt

> May not removes certain bacteria

> Causes demineralization of water.
> Gives lowest TDS water
> High water flow rate

> Does not remove salts, fluoride, or TDS dissolved in water.

> Less Maintenance

> Does not change chemical property of water.

> Requires Electricity

> Works well with normal tap water pressure.

> Since there is no filtration so dead microorganism remain in water, although not harmful  
> Retains beneficial minerals in water

> Does not need electricity

> Does not remove salts, fluoride, or TDS dissolved in water.

> Works well with normal tap water pressure

> Less price & low maintenance

> No water wastage

> Removes microbiological contamination completely  
Best suited for Water having TDS value >500 mg/L > Water having TDS value < 500 mg/L

> Obtaining water 100% free from waterborne pathogens.
Water having TDS value < 500 mg/L
Results Low TDS water without any minerals or salt, microbe may remain Water safe from any microbe disinfection but does not affect minerals and salt presence. Water free from any microbe but does not affect minerals and salt presence.

Therefore in order to find out which type of water purifier you should be buying you need to go for water test of your home water first.

You may check here test your water.

9. Which combination of purifier should we go for RO purifier?

If you take NF + RO, there is chances of membrane getting bursted later after 2 yrs or so, there are chances at that time that some bacteria may enter the water.

Instead if you prefer NF/RO+ UV with same, UV is helpful for curbing bacteria / virus & micro-organisms, the process is it will rupture the cells of bacteria and thus it curbs the reproduction capacity of the bacteria within 20-25 mins of its life span, and the count does not get multiplied thus u get protection from bacteria / virus also along with filtration of heavy metals. 

10. What Storage capacity purifier should we buy?

Water purifier comes with storage and without storage. Some UF and Activated Carbon filters that getdirectly fixed to the water tap does not have storage for purified water.

So which should you go for?

If you are living in locality that is having frequent power cuts or unreliable water supply, it is advised to buy a purifier with a storage tank. If you are having medium or large family, you should be considering water purifier with storage tank for better continuous supply of water.


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