AO Smith Z3 review: under-sink RO+UV with a 6 L no-power tank, but no app
AO Smith Z3 under-sink purifier, ₹29,990 MRP: 8-stage RO plus UV LED and a 6 L tank that works in power cuts, but no app and only a 1-year warranty.
- Tested for Testing in progress
- We bought this unit
Where to buy
- Official store ₹29,990Check price
Prices checked 31 Oct 2026. Prices change often. Plain retailer links — we earn no commission when you buy.
Disclosure: Draft: specs come from launch coverage and AO Smith India’s product list. Our own measurements are in progress and the scores are provisional.
The verdict
The AO Smith Z3 is an under-sink RO plus UV LED purifier with copper and alkaline stages and a 6 L hydropneumatic tank that dispenses without power, listed from ₹29,990. It has no app, a slow 15 L/hour flow and a 1-year warranty, so it costs more than the Boon Tap and offers less.
Best for
- Buyers who want an AO Smith under-sink unit and care about dispensing during power cuts
- Borewell or tanker water up to 2,000 ppm
Skip it if
- You want an app or any TDS and filter monitoring
- You want a warranty longer than one year
What we like
- 8-stage RO plus UV LED with copper mineraliser and alkaline stage; about 95% TDS reduction and up to 55% recovery (launch coverage)
- 6 L hydropneumatic tank lets you draw stored water without electricity
- Rated for borewell and tanker water: input TDS up to 2,000 ppm and hardness up to 500 ppm
- Digital display; wheels and a handle make the unit easier to move
What we don’t
- No app or smart connectivity
- Flow is up to 15 L/hour, slower than the Boon Tap’s rated 20 L/hour
- Only a 1-year comprehensive warranty (RO membrane, filters and electrical parts)
- The UV is an LED with no published wavelength, power or dose, so we do not count it as proven disinfection
- The "antioxidant water" claim is marketing and is not independently tested
Score breakdown
- Purification and water quality
- 7.5
- Design and installation
- 7.0
- App and monitoring
- 3.0
- Warranty and service
- 6.5
- Value
- 6.0
In this review
How we tested
We compare under-sink purifiers on the same checklist: purification and input-water limits, mineral control, the UV stage, what the sensors measure, how good the app is, the tap and installation, warranty and service, and price. Specs here come from launch coverage; our measurements are being added.
Purification and the tank
An 8-stage line with RO, a UV LED, a copper mineraliser and an alkaline stage, rated for up to 2,000 ppm TDS and 500 ppm hardness. The 6 L hydropneumatic tank is the standout practical feature: it keeps dispensing during a power cut. Flow is up to 15 L/hour.
The UV stage
The Z3 uses a UV LED. AO Smith does not publish its wavelength, power or dose, so we list it as unpublished and do not count it as proven disinfection, the same standard we apply to every purifier.
What it lacks: any app
There is no app, so you cannot see TDS or filter health, and a digital display is all you get. That is simple, but it is not “smart”, and it means you cannot confirm the RO is working without your own meter.
Warranty and service
One year comprehensive covering the membrane, filters and electrical parts. That is the shortest warranty in this comparison alongside Eureka Forbes.
Should you buy it?
Buy it if you want an AO Smith under-sink unit that works through power cuts and you do not need an app. At ₹29,990 MRP, it costs more than the Boon Tap and offers less.
Key specs
| Type | Under-sink water purifier, RO + UV LED |
|---|---|
| Purification | 8 stages: RO, UV LED, copper mineraliser, alkaline |
| Tank | About 6 L hydropneumatic tank (dispenses without power) |
| Mineral control | Copper mineraliser and alkaline stage; marketed as antioxidant water; no selectable modes |
| UV stage | UV LED; wavelength, power and dose not published |
| Input TDS limit | Up to 2,000 ppm; hardness up to 500 ppm |
| Purification rate | Up to 15 L/hour; recovery up to 55%; about 95% TDS reduction (manufacturer) |
| Sensors and what they measure | Not specified; no TDS or water-quality sensor listed |
| App and IoT | None |
| App rating and reliability | Not applicable: no app |
| Display | Digital display |
| Tap and installation | Faucet included; 420 x 450 x 265 mm, about 11.5 kg; wheels and handle; 230 V, up to 48 W; 5 to 30 psi |
| Warranty | 1 year comprehensive: RO membrane, all filters and electrical parts |
| Running cost | Not published |
| Reported price | ₹29,990 MRP (Onyx Black); no street price found |
| Claims to verify | "India’s first under-sink purifier with antioxidant water", 95% TDS reduction and 55% recovery are manufacturer claims |
Questions buyers ask
Does the AO Smith Z3 have an app?
No. The Z3 has a digital display but no app, Wi-Fi or TDS readout in the launch coverage we found.
Can the AO Smith Z3 dispense water during a power cut?
Yes, according to launch coverage. Its 6 L hydropneumatic tank lets you draw stored purified water without electricity.
What warranty does the AO Smith Z3 have?
One year comprehensive, covering the RO membrane, all filters and electrical parts, per launch coverage.
Does the AO Smith Z3 use real UV purification?
It lists a UV LED, but AO Smith does not publish the UV wavelength, power or dose that we found. Like every purifier we review, we treat that as unpublished rather than proof of disinfection.
