Top 3 Under Sink RO Water Purifiers – Buying Guide!

Water purifiers have become a necessity today because of the highly contaminated water resources.

The release of industrial and human wastes into the water bodies has caused this situation.

Therefore, you find the presence of heavy metals like arsenic, lead, and mercury in addition to the normal TDS (Totally Dissolved Solids).

There are various kinds of water purifiers available in the market. The ‘Under the counter’ or ‘under the sink’ type of water filter is slowly gaining in popularity.

One of the principal reasons is that the kitchens in the nuclear Indian family homes are getting smaller. These water purifiers save a lot of space while doing the job of water purification. Hence, you find many people opting to buy these water filters.

Under Sink Water Purifier – Buying Guide

Let us now look at the simple points to have in mind while purchasing the ‘under the sink’ water purifier.

Easy to install – Normally, all water purifiers are easy to install. The ‘under the sink’ water purifiers are no different in this regard.

Easy on your budget – In addition to providing highly efficient services, the ‘under the sink’ water filters are easy on the budget, both on the purchase and the upkeep front.

Easy to maintain – These water purifiers do not require much maintenance other than regular replacing of the filters.

Save space – The modern day Indian kitchen is shrinking in size. These water purifiers provide the best alternative as you can place them below the kitchen sink.

Good quality models available – Kent and A O Smith are two of the top models that come to mind when you talk about such water purifiers. They are the market leaders in other types of water filters as well.

Types of ‘under the sink’ water purifiers

Basically, you have two types of ‘under the sink’ water filters, the inline filters, and the regular water filters. Let us see the basic difference between the two.

There is not much difference between the two. The inline filters are installed in-line on your normal water source line with push fittings. In the case of the regular filters, you need to split the mains line using a T-connector and install a separate filter tap.

The inline filters are comparatively difficult to install. However, they allow you to keep on using your kitchen tap as they filter the water flowing through this tap as well. In the case of the regular filters, you need to add another tap to the filtered water alone.

Hence, you would have two different taps in the kitchen sink. However, these filters are easier to install.

Normally, you have to opt for a single cartridge filter if you have an inline filter. Some of the modern models do have multiple cartridges. The regular filters are usually multi-stage filters.

Disadvantages of the ‘under the sink’ water filters

It is necessary to know the advantages and disadvantages of any appliance before buying the product. Let us look at some of the disadvantages of these water purifiers.

Like all water filters, they are normally installed at a single point of use. Hence, these filters will purify the water at that particular water outlet alone. In case you wish all your outlets to have access to filtered water, you should install a whole house filter.

Another disadvantage is that you need to install a separate tap while using these water filters. Alternatively, you can have a three-way kitchen sink tap that can dispense hot, cold, and the filtered water from a single outlet.

Points to note in mind

These filters are gradually gaining in popularity. Hence, not many people are aware of the functioning of these water purifiers. These following points will be extremely useful to you while looking out for such water filters.

Filtration efficiency

You judge the efficiency of a water purifier by its contaminant removal capacity and the filtered water output. Therefore, it makes sense to opt for water filters that can eliminate the maximum contaminants without compromising on the output flow rates.


Though people say that you will be able to install these filters on your own, it is always better to rely on the professional to do his job.


It is better to opt for filters that do not require much maintenance. Normally, these water purifiers require changing of filters alone.


People make the mistake of looking at the initial cost while purchasing water purifiers. You should also factor the maintenance costs and the costs you are likely to incur for changing the filters at frequent intervals.

Tap compatibility

If you go for an inline filter, there is not going to be an issue at all. However, if you opt for a regular filter, you should go for a three-way tap that can dispense hot, cold, and the filtered water from a single location.

Best Under the sink Water Purifiers

Kent and A O Smith are two names that immediately come to mind when you venture to purchase ‘under the sink’ water purifiers. We shall review 3 water filters for your benefit.

Kent Excell+

Kent has a reputation for being one of the most popular brands of water purifiers in India. They have a product in this category of ‘under the sink’ water filters. The category may change but the quality of the product or design does not. Working on Kent’s patented Mineral RO Technology, this water purifier comes with an in-built TDS controller.

Having a capacity of 7 litres, this water filter is perfectly suited for the Indian kitchen needs. Capable of purifying brackish water as well as municipal tap water, this product comes with a 4-year free service claim. This includes the manufacturer’s warranty of 1 year.

The Mineral RO technology ensures that the output water does not lose any essential minerals that you would normally see in RO water purifying systems. Hence, you get water that is 100% safe and tasty at the same time.

This water purifier comes with the double purification of RO and UV/UF. Hence, it is capable of taking care of all kinds of impurities, bacteria, viruses, TDS, and other chemical impurities like pesticides, etc.

  • Excellent design that not only looks aesthetic but performs admirably as well
  • Certified by the world’s renowned laboratories like WQA and NSF.
  • Patented Kent Mineral RO technology
  • Double purification RO + UV/UF
  • Being an RO filter, you can expect wastage of water

A O. Smith X5

A. O. Smith is one of the world-renowned names as far as water purifiers are concerned. Famous all over the world, A. O. Smith has entered the Indian markets in a big way. The A. O. Smith X5 ‘under the sink’ water purifier is one such contribution from the A. O. Smith stable.

Having a storage capacity of 7.5 litres, this water filter is very popular among the normal Indian households. The highlight of this water filter is the 5-stage purification process. This includes the Pre-filter, sediment filter, pre-carbon filter, RO membrane, and solver activated post carbon filters.

This water purifier can purify water with TDS levels up to 2000 ppm. It claims to waste less water in comparison to other RO water filters. This appliance comes with an advanced pre-filter and sediment filter for elimination of suspended solids.

The gooseneck faucet is a special feature that adds to the convenience of the user. This water filter uses state-of-the-art RO membrane technology for purification.

  • 5-stage filtration process
  • Tested and certified by world-class laboratories like WQA
  • No UV/UF purification

A O Smith Z2

This is a smaller water filter with a storage capacity of 5 litres. A O Smith brings its patented SSM Technology (Side Stream RO Membrane) technology to India. The advantage of this technology is that it reduces water wastage that you otherwise observe on RO water purifiers.

The 5-stage purification consisting of the Pre-filter, sediment filter, pre-carbon filter, RO membrane, and silver activated post-carbon filter ensures that you get the highest levels of purification. This filter comes with a system whereby it alerts you when it is time to change the filters.

The digital display and the gooseneck faucet are other attractive features.

  • Certified by WQA
  • Patented SSM technology that reduces wastage of water
  • No UV/UF purification


The ‘under the sink’ water purifier is a novelty in the Indian market today. It is gradually becoming popular because of its various inherent advantages. The greatest advantage of this water purifier is that it saves a lot of space. It does not require much maintenance other than the regular changing of filters.

However, one should maintain great hygienic values as these filters are placed below the kitchen sinks. These are locations that demand maintenance of high values of hygiene.

2 thoughts on “Top 3 Under Sink RO Water Purifiers – Buying Guide!”

  1. Hi, thanks and appreciate your effort in helping people like me in making a quick decision.

    I would prefer not to go with RO but just a UV/UF with sediment filter similar to Kent Ultra. Is there any under sink options.


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