A. O. Smith Z3 (Onyx Black)

A. O. Smith Z3 (Onyx Black) is an under-sink RO + UV LED + Antioxidant + Copper + Alkaline water purifier with a 6-litre tank and a purification rate of 15 litres an hour. A. O. Smith says it handles input water up to 2,000 ppm TDS. Stated water recovery is 55%. It is one of 6 A. O. Smith water purifiers and 69 water purifiers compared on Comparezi.

A. O. Smith Z3 (Onyx Black) at a glance

• Technology: RO + UV LED + Antioxidant + Copper + Alkaline
• Storage: 6 litres
• Purification rate: 15 L/h
• Max input TDS: 2,000 ppm
• Water recovery: 55%
• Stages: 8
• Installation: Under sink
• Warranty: 1 year

Purification

A. O. Smith lists the purification as RO + UV LED + Antioxidant + Copper + Alkaline. RO (reverse osmosis) removes dissolved salts, which matters when your water's TDS is high (borewell or tanker water); for low-TDS municipal water it is often not needed. UV treats bacteria and viruses. It also has copper/zinc infusion and an alkaline stage, as described by A. O. Smith. Stated maximum input TDS: 2,000 ppm. Test your water (a TDS meter costs little) before choosing.

Capacity and water use

The tank holds 6 litres. It purifies about 15 litres an hour, as stated. Stated water recovery is 55%: for every 100 litres that go in, about 55 litres come out purified and 45 litres go to the drain. Rated power: 48 W. Installation: under sink. Tank material: Food safe, non-toxic, engineering grade plastics.

Running and ownership

Warranty: 1 year (Z3 comes with 1 year comprehensive warranty that covers all filters, RO Membrane and electrical parts.). Filters and the RO membrane are a running cost; ask the brand for the annual maintenance plan price before you buy.

How the A. O. Smith Z3 (Onyx Black) compares

Of the 66 water purifiers on Comparezi with a stated tank size, 41 have a bigger tank and 9 are level with it. Of the 40 water purifiers on Comparezi with a stated purification rate, 30 purify faster and 8 are level with it. Of the 21 water purifiers on Comparezi with a stated water recovery, 10 waste less water.

Similar water purifiers from other brands

• Aquaguard Enrich Glory RO+UV+UF 2X Copper Alkaline: RO+UV+UF + 4-in-1 Active Copper + Alkaline Boost, 6 L (compare with the Z3 (Onyx Black))
• Aquaguard Enrich Nexen 2X RO+UV Active Copper Alkaline: RO+UV + 4-in-1 Active Copper + Alkaline Boost, 6 L (compare with the Z3 (Onyx Black))
• Aquaguard Sure Delight 2X Aquasaver RO+UV+UF: RO+UV+UF with Aquasaver Mineraliser Technology, 6.2 L (compare with the Z3 (Onyx Black))
• Aquaguard Sure Delight 2X RO+UV: RO+UV (NanoPore RO 2X, UV e-boiling), 6.2 L (compare with the Z3 (Onyx Black))

Other A. O. Smith water purifiers

• A. O. Smith P8 Pro: RO + Antioxidant + Copper + Alkaline + Silver Shield (SCMT), 5.7 L (compare)
• A. O. Smith X9 Black: 100% RO + SCMT (Silver Shield) + Copper Fortified Mineraliser + Alkaline, 5 L (compare)
• A. O. Smith U2 Pro+: Next-Gen UVC LED (TwinPure) + Copper Mineraliser, 6 L (compare)

See every A. O. Smith product on Comparezi.

Sources

• Brand page (aosmithindia.com)
• Brand store page (aosmithindia.com)

Checked 18 October 2026. Figures the brand does not state are left out rather than estimated. Prices on this page come from dated store checks, not from this text. See how Comparezi checks data.