KENT vs A.O. Smith Water Purifiers For Home: Which Model Is Good For Hard Water? (September 2026)

Confused between KENT and A.O. Smith for hard or borewell water? Discover some of the popular water purifiers from these brands and compare them by purification stages, tank capacity as well as everyday usability, so you can pick a model that actually matches your water source and household size.

By: Esha Jha
Last Updated on: Sep 07, 2026 14:20 IST
Published on: Sep 07, 2026 14:15 IST
KENT vs A.O. Smith Water Purifiers For Home

Hard water is very common nowadays, especially among Indian households who are dealing with borewells, tankers or mixed municipal water. However, this bad water quality will be evidently visible by the formation of scales on kitchenware, dryness of skin after taking a bath and non-formation of foam even when using soap. 

While a water purifier will not solve the problem of hardness in the pipelines, an effective RO water purifiers for home will definitely reduce the presence of dissolved solids and contaminants in drinking water. 

Some of the top water purifier brands that manufacture such purifiers are KENT and A.O. Smith, which are compared here using six of their top-selling water purifiers from these brands.

01

KENT Grand RO Water Purifier

4.4

₹12899

Quick Overview of This Water Purifier:

  • RO + UV + UF + TDS Control purification
  • Zero Water Wastage Technology
  • UV LED disinfection inside the storage tank
  • 8 to 9 litre storage capacity
  • Wall-mountable design
  • Mineral RO Technology to retain natural minerals

Is KENT Grand RO Right for You and Your Family?

  • KENT Grand RO water purifier is one of the reliable and user-friendly devices for families who are basically dependent on municipal or tap water with an average TDS level and are dealing with hard water.
  • Moreover, the triple-layered filtration technology of RO+UV+UF purification stages of this Kent water purifier efficiently takes care of contaminants, bacteria, and viruses in the water.
  • Also, in addition to the above mentioned benefits, the zero-wastage technology of KENT Grand RO redirects the rejected water to the overhead tank of the family rather than wasting it, especially for those who have water scarcity problems in their areas

Technical Specifications:

  • Brand: KENT
  • Model: Grand RO Black
  • Capacity: 8 Litres
  • Item Dimensions: 39L x 25W x 53H Centimeters
  • Purification Stages: Multiple Purification Stages

How Is This Kent Grand RO Water Purifier Better Than AO Smith Z9 Pro? 

KENT Grand RO skips the standby heating that Z9 Pro needs for hot water, so it suits budget-conscious homes without that daily need.

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Reasons to buy

  • Zero water wastage
  • Mineral retention

Reasons to avoid

  • Average TDS
02

AO Smith Z9 Pro Instant Hot and Ambient Purifier

4.2

₹23990

Quick Overview of This Water Purifier: 

  • RO + SCMT + Copper + Alkaline Mintech, 8-stage purification
  • Instant hot water at 45 degrees Celsius and 80 degrees Celsius
  • Ambient (room temperature) water dispensing
  • 10-litre stainless steel storage tank
  • Advanced Recovery Technology for better water saving
  • Digital display with child lock

Why Choose the Z9 Pro? Unmatched Advantages for Your Family 

  • If you are someone who depends mainly on tea, coffee or even ready-to-eat meals for most of their daytime, then the major advantage you can have with the Z9 Pro model of AO Smith water purifier is not having to boil the water again and again.
  • However, in addition to 8 Stage RO and SCMT purification technology, it tends to provide you with 45 degrees Celsius and 80 degrees Celsius water instantly, other than ambient temperature water.
  • Apart from the above listed features, the stainless steel body and Advanced Recovery Technology also makes it durable and efficient, thereby suitable for households which depend on hot water frequently.

Technical Specifications:

  • Brand: A. O. Smith
  • Model: Z9 Pro
  • Capacity: 10 Litres
  • Item Dimensions: 14.5L x 12.8W x 19H Centimeters
  • Purification Stages: 8 Stage Purification

How Is This AO Smith Z9 Pro Water Purifier Better Than Kent Grand RO? 

Z9 Pro adds instant hot and ambient dispensing that KENT Grand RO does not offer, useful for tea, coffee, or baby formula needs.

Reasons to buy

  • Instant hot water
  • Stainless steel tank

Reasons to avoid

  • Higher pricing
03

KENT Supreme Plus Alkaline+Copper RO Water Purifier

4.1

₹15599

Quick Overview of This Water Purifier: 

  • RO + UV + UF + Alkaline + Copper + TDS Control, 6-stage purification
  • Auto flush technology for the membrane
  • 20 litres per hour purification capacity
  • Wall-mounted design
  • 1-year free service plan

Why Choose the KENT Supreme Plus for Your Home? 

  • One should choose this particular KENT RO water purifier because this Supreme Plus model has been designed keeping in mind the customers who wants to know about alkaline and copper water capability before choosing a water purifier for home.
  • This is because, apart from the regular RO + UV + UF filtration system, this model also has a unique feature of having alkaline and copper filters and a TDS controller. 
  • Along with this, this Kent purifier also comes with an auto-flush system that aims to help increase the longevity of its RO membrane. 
  • And therefore, this purifier is meant for people who are looking for both purification as well as mineral benefits in a single product.

Technical Specifications:

  • Brand: KENT
  • Model: KENT Supreme Alkaline Black
  • Capacity: 8 Litres
  • Item Dimensions: 40L x 25W x 52H Centimeters
  • Purification Stages: Multiple Purification Stages

How Is This KENT Supreme Plus Water Purifier Better Than AO Smith Z5? 

KENT Supreme Plus adds a dedicated copper filter for mineral-enriched water, a feature AO Smith Z5 does not include at this price.

Reasons to buy

  • Copper enrichment
  • Auto membrane flush

Reasons to avoid

  • Limited capacity
04

AO Smith Z5 Water Purifier

4.2

₹14499

Quick Overview of This Water Purifier: 

  • RO + SCMT with Alkaline Min-Tech, 8-stage purification
  • Digital display for power mode, tank level, and filter alerts
  • Wall-mount and tabletop placement options
  • Purified water pH range of 7 to 8.5
  • Suited for borewell, tanker, or mixed water sources

Why Choose the AO Smith Z5: Advanced Protection for Your Family?

  • When you are looking for a sure and stable water solution for your family, then this AO Smith Z5 water purifier can help you out, as it is specifically made for borewell and mixed hard water sources where the TDS value is usually very high. 
  • This is taken care of by the RO and SCMT system, while the Alkaline Min-Tech AO Smith filter ensures that the filtered water is slightly alkaline, having a pH value ranging from 7 to 8.5. 
  • Moreover, this AO Smith purifier also comes with a digital display that can show tank and filter statuses, which is helpful for people who generally forget when to change the filters. 

Technical Specifications:

  • Brand: A. O. Smith
  • Model: AO Smith Z5 Water Purifier
  • Capacity: 5 Litres
  • Item Dimensions: 15L x 38W x 46H Centimeters
  • Purification Stages: 8 Stage Purification

How Is This AO Smith Z5 Water Purifier Better Than KENT Supreme Plus?

AO Smith Z5's digital display shows real-time filter alerts, a convenience KENT Supreme Plus does not offer at a similar price point.

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Reasons to buy

  • Borewell compatible
  • Filter alerts

Reasons to avoid

  • Smaller tank
05

KENT Supreme IoT RO Water Purifier

4.3

₹18999

Quick Overview of This Water Purifier: 

  • RO + UV + UF + Alkaline + Copper + TDS Control, 6-stage purification
  • IoT-enabled real-time display of water quality and filter life
  • Automatic service alert on fault detection
  • 20 litres per hour purification capacity
  • Enhances purified water pH to around 8 to 9

The Advantages of Choosing KENT Supreme IoT and What You Need to Consider Before You Buy

  • In case you are among those people who want to stay informed about the state of things inside your purifier, then KENT Supreme IoT water purifier is for you, as it shows you real-time water quality and filter life.
  • In addition, this Kent RO also alerts you about any maintenance concerns on its own, hence taking out all the troubleshooting on your part. 
  • Apart from all these monitoring features, this water purifier from KENT consists of similar RO + UV + UF + Alkaline + Copper purification systems that are available in other Supreme purifiers by the brand.

Technical Specifications:

  • Brand: KENT
  • Model: KENT Supreme IoT
  • Capacity: 8 Litres
  • Item Dimensions: 32L x 36W x 50H Centimeters
  • Purification Stages: 6 Purification Stages

How Is This KENT Supreme IoT Water Purifier Better Than AO Smith Z5 Pro? 

KENT Supreme IoT tracks water quality and filter life in real time on-device, a monitoring layer AO Smith Z5 Pro does not offer.

Reasons to buy

  • Real-time monitoring
  • Service alerts

Reasons to avoid

  • Bulkier design
06

AO Smith Z5 Pro RO Alkaline Water Purifier

4.1

₹15999

Quick Overview of This Water Purifier: 

  • RO + CFM Alkaline purification
  • Compact 5-litre storage tank
  • Digital display
  • Wall mount and tabletop placement options
  • Auto flush indicator

What Makes the Z5 Pro Stand Out From Other Water Purifier Models? 

  • The AO Smith Z5 Pro RO water purifier will be a great choice for families living with constrained kitchen space as well as for families who would like to have an alkaline water purification unit.
  • This is because, with a 5-litre capacity tank, this unit has a small footprint compared to other water purifiers in this comparison, along with RO technology, CFM, and a digital control panel that can provide you with all basic features without increasing its size.
  • Apart from this, it works well for smaller families or single-person households that do not need a large storage tank refilling throughout the day.

Technical Specifications:

  • Brand: A. O. Smith
  • Model: AO Smith Z5 Pro Water Purifier
  • Capacity: 5 Litres
  • Item Dimensions: 38L x 26.7W x 46H Centimeters
  • Purification Stages: 8-stage Purification

How Is This AO Smith Z5 Pro Water Purifier Better Than KENT Supreme IoT?

AO Smith Z5 Pro comes with a compact footprint with 5 liter storage capacity that suits smaller kitchens better than KENT Supreme IoT that has a bulkier and wall mounted design.

Reasons to buy

  • Compact footprint design
  • Tabletop placement

Reasons to avoid

  • 5L capacity only

Head-to-Head Comparison Between KENT vs A.O. Smith Water Purifiers: Filtration Stages, Capacity & Features

Product Name

Filtration Stages

Capacity

Suitable For

KENT Grand RO

RO+UV+UF+TDS Control

8 L

Municipal or tap water homes with standard TDS

AO Smith Z9 Pro

RO+SCMT+Copper+Alkaline (8-stage)

10 L

Households needing hot water on demand

KENT Supreme Plus

RO+UV+UF+Alkaline+Copper (6-stage)

8 L

Buyers prioritising alkaline and copper water

AO Smith Z5

RO+SCMT+Alkaline Min-Tech (8-stage)

5 L

Borewell, tanker, or mixed-source water

KENT Supreme IoT

RO+UV+UF+Alkaline+Copper (6-stage)

8 L

Buyers who want visibility into purifier performance

AO Smith Z5 Pro

RO+CFM Alkaline

5 L

Small kitchens, single or two-person households

Maintenance & Running Costs: KENT vs A.O. Smith Water Purifier

Running costs for any water purifier largely depend on the quality of the water you are using as the input rather than the brand.

  • TDS or harder water puts greater pressure on the RO membrane as well as pre-filters, which results in shorter replacement cycles compared to RO purifiers that operate on relatively cleaner municipal water.
  • Purifiers such as KENT Supreme Plus and KENT Supreme IoT come with the auto-flush feature, which means less strain for the membrane during operation, but filter life will still depend on how often it needs servicing. 
  • Since both companies provide an annual maintenance contract through their service centres, it is better to check the pricing of the AMC offered by KENT and A.O Smith for your city before comparing the running costs, as the number might differ.

Frequently Asked Questions:

What should be the ideal TDS value of the drinking water? 

As per the norms of the Bureau of Indian Standards, drinking water whose TDS value is less than 500 ppm is usually acceptable, while that which is more than 900 ppm is not recommended. 

How frequently should one replace their filters in hard water situations? 

Hard water or high TDS water, as in the case of borewell water supply, wears out the filters and membranes faster than soft water supplied through the municipality. Rather than sticking to any fixed date, it is better to rely on the filter change signal on your purifier or get it inspected every once in a while.

Do KENT or A.O. Smith purifiers add minerals back into the water? 

Yes, the majority of units available under both brands employ mineral retention or alkaline technology like Mineral RO Technology from KENT and Min-Tech from A.O. Smith, which adds back the minerals lost by regular RO filtering while slightly increasing the pH of the water.

What is the distinction among RO, UV, and UF technologies for hard water? 

RO technology separates dissolved solids and heavy metals; hence, it works for hard water because of this property. UV purification technology kills germs through radiation by UV light; however, it does not remove any dissolved solids itself. UF (ultrafiltration) removes suspended particles and certain microorganisms through the process of filtration but does not reduce TDS.

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