What is a water purifier?
The water that is supplied to our homes is laden with many impurities. These can be undesirable chemicals, heavy metals, suspended particulates and germs. A domestic water purifier filters out all this so that you can have clean drinking water at home.

Earlier, most households used to boil water before drinking. Another process was using disinfectants like Zeoline to make water safe.

While these are safe methods, they are inadequate to ensure safety.

Boiling water doesn’t kill germs until it is done for 20 minutes. This meant a lot of fuel consumption. Neither boiling nor liquid water purifiers can get rid of solid particulates or chemicals dissolved in the water.

A water purifier filters out almost all undesirable materials, while preserving essential minerals in the water. Most domestic water purifiers use a multi-barrier screen with activated carbon to eliminate these impurities.

Post carbon filtration, the water is collected through a water dispenser. Usually, there is a waiting time between switching on the purifier and collecting the water, during which purification happens.

What is the different type of water purifiers?
There are many water purifiers available on the market. They are classified into the following categories based on the filtration processes they use.

1. Gravity Based Water Purifiers
These are simple purifiers, in which water is filtered as it passes from the top layer to the bottom.

In gravity-based water purifiers, there are several vertical barriers that filter out one type of impurity each. So on the top you may have a layer that kills germs, the next may filter out fine particles and another may filter our dust and dissolved particles.

Some of these today also use a UV filter to clean out minute solubles. Gravity based water purifiers are usually the cheapest models. They can also hold a large amount of water and can be easily transported.

However, gravity-based water purifiers cannot get rid of heavy metals like arsenic and mercury- which occur frequently and are dangerous to health. They are also not as effective against germs.

2. RO Water Purifiers
RO stands for “reverse osmosis”. These are common in many household machines. In RO purifiers, water is passed through a semi-permeable member under high pressure.

This filters out heavy metals like arsenic and mercury, and other salts like nitrates and fluorides.

RO water purifiers are in the mid-price range, depending on the filtration membranes they are using, and their storage capacity. They are widely used in areas where the water is hard and is sourced from borewell or tubewell.

RO water purifiers can get rid of the metallic taste of water.

However, RO purifiers need electricity to purify water and waste a lot of water during the purification process. Moreover, they are not as effective at filtering out bacteria and virus.

3. UV Water Purifiers
UV stands for “ultraviolet”. These water purifiers use ultraviolet technology to kill bacteria and virus. The water passes through various filters during which all germs are killed.

UV filters effectively stop the spread of water-borne diseases like dysentery, cholera and typhoid. They also do not leave the water an acidic taste, unlike RO purifiers.

UV water purifiers do not destroy the dissolved minerals and salts in the water. However, they also cannot get rid of heavy metals like mercury and arsenic.

4. UF Water Purifier
UF water purifiers use ultra-filtration technology. These ultra-filtration layers have pores that are slightly larger than that of RO filters. While these filters kill germs passing through them, they keep the dissolved salts intact.

UF water purifiers do not need electricity to purify water and are considered the best for removing germs and impurities from muddy water.

They are long-lasting and can be cleaned manually by flushing out all the germs from the filters. However, UF filters are also ineffective against heavy metals.

5. Universal Water Filters
These use a combination of all the water filtration methods. Most companies make purifiers that combine two or three of the above-mentioned methods for their products.

Below are some of the popular technological combinations:

RO+UV: This is the most optimal combination of technology. These purifiers give the best quality water. They use both reverse osmosis and ultraviolet technology to remove germs, heavy metals and dissolved impurities.

RO+UV+UF: These water purifiers clean water of all kinds of impurities. Some companies add all these technologies to make sure the water they give is 100% clean. However, these are usually costlier than other purifiers and are also high maintenance.

Pre-post activated carbon: These water purifiers are effective in flushing out toxic chemicals and pesticides. Activated carbon blocks impurities that otherwise stick to the RO filters and reduce their life cycles.

Universal water filters can be used to purify all kinds of water, and they also enhance the taste by adding the required minerals. They filter out toxic chemicals, dust, impurities, heavy metals and germs. However, these also require electricity and are not portable.

Now that you know all about the characteristics of water filtration technology available, it is time to decide what to buy for your home. Below are some of the best and most popular models available on the market.

Best Water Purifiers for Your Home
1. Unilever Pureit Classic 23L: Best Non-Electric Water Purifier In India
Company: Unilever
Type: Purify and storage
Electricity: No
The technology used: Activated Carbon