A.O. Smith X4 Water Purifier Review

  • Editor Rating
  • Rated 3 stars
  • 60%

  • Build
    Editor: 55%
  • Technology
    Editor: 65%
  • Design
    Editor: 60%
  • Service
    Editor: 60%
  • Price
    Editor: 50%


  • Strong Filters
  • Simple and Neat Design


  • Pricey
  • Lacks UV filtration

A.O. Smith X4 Water Purifier Review: A.O. Smith X4 is a 100% RO water purifier with 2 year warranty on the RO membrane. It incorporates a 5 stage purification system, along with Side Stream RO Membrane Technology.

A.O. Smith Corporation is an American manufacturer of both residential and commercial water heaters and boilers and it is the largest manufacturer of water heaters in North America. The company has 24 locations worldwide and have recently set their footprint in India with the launch of water purifiers and water heaters.

Having reviewed over 50 water purifier models across different brands in India, I’ve got my hands on the A.O. Smith X4 water purifier and here’s my review.

Build: A.O. Smith X4 is made with food grade, non-toxic, engineering grade plastics. Such plastic is considered nontoxic and BPA free, this keeps the water bacteria free even when stored for longer duration. The water purifier is flexible to be  installed on a table top or wall mounted and it does not eat up the kitchen real estate, thanks to its  W314 x D325 x H503 (mm) dimensions that make it  look really neat . The body corners are neat, elegant without any sharp corners or gaps between the side panels. The large 9 liter water tank is sufficient to hold enough water required through the day. There isn’t enough gap between the water dispenser and the drip tray to fill a large water bottle, however, you have an option to remove the drip tray while filling large water bottles.

Technology: A.O. Smith X4 water purifier is equipped with a basic 5 stages of purification system, wherein the water is passed through the various stages and progressively filtered to get purified water which is stored in the inbuilt storage tank.

  1. Stage 1 – Pre-filter: The Pre-filter is used to remove physical contaminants such as dirt, dust, soil particles, turbidity present in the water. This improves the life of the Sediment filter.
  2. Stage 2 – Sediment filter: The Sediment filter is used to remove fine and coarse physical contaminants present in the water.This improves life of the Pre Carbon filter and ensures efficient working of RO membrane.
  3. Stage 3 – Pre carbon filter: The Pre Carbon filter uses carbon block with high adsorbtion capacity which reduces harmful chemicals including pesticides, volatile organic compounds, residual chlorine etc., from water. It also adsorbs bad taste and odour causing organic compounds from water.
  4. Stage 4 – RO (Reverse Osmosis) membrane: RO membrane contains semi-permeable membrane wherein the water is passed through the semi-permeable membrane to remove TDS (Total Dissolved Solids) and heavy metals like mercury, arsenic, lead, chromium, cadmium etc. It also removes microorganisms like bacteria, virus, protozoa and cysts.
  5. Stage 5 – Silver Activated Post Carbon: Water is passed through Silver Activated Post Carbon which acts as polisher and enhances the taste of water.

These powerful filters can remove TDS greater than 95% and help in water recovery up to 30% without slowing down the water flow rate at 15 liters per hour. The water purifier is equipped with an inbuilt stabilizer to handle input voltage capacity between 150 to 300 VAC. A simple non-digital dashboard is easy to read with its basic indicators that has a power button, tank full indicator, auto flush indicator, RO change indicator and Silver Carbon indicator that glow when their remaining life 10%, this gives you sufficient time to re-order filters. The auto flush feature is quite useful to clean the RO membrane and improve its life.



Design: A.O. Smith X4 Water Purifier is a well designed and simple to use device. The white body color blends well with most of modular kitchen designs and you have an option to choose from 4 front body panel colors. The water dispensing faucet is easy to use when you want to dispense a glass of water, but if you want a large bottle of water, you will have to remove the drip base and lift the water faucet upwards for continuous flow, it’s just that you have to get used to the design and its not really a rock lifting task.

Service & Price: A.O Smith is headquartered in Bengaluru, Karnataka and has regional presence in Mumbai and Delhi. A.O. Smith water purifiers are sold and serviced in major cities of India and the company plans to expand its presence to other cities very soon. The pre-filters and sediment pre-carbon filters have an average lifespan of 2500 liters and the expensive RO membrane can purify between 6000 to 12000 liters of water depending on the input quality. You also have an option to sign up for an annual maintenance contract that shields your investment. A.O. Smith X4 water purifier is retailing at ₹ 16,750.00 and is available online at Amazon.in from ₹ 14,790.00, customers are eligible for the same 2 year warranty and free installation when purchased online at Amazon.in.

Conclusion: A.O. Smith X4 water purifier is best suited for corporation or municipal water, it does its job with simple design and strong 5 stage water purification technology. The device lacks UV purification and post-carbon filtration to handle any source of water, at the price point of ₹ 16,000.00, you have plenty of choice to pick from, I would personally reccomend the all-round Pureit Ultima RO+UV.  

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