Under-Sink vs Wall-Mounted Water Purifier: Which Suits Your Kitchen?

Most under-sink purifiers sold in India are tankless direct-flow units, or carry a tank of two to four litres at most, because cabinet space is limited. That is fine on continuous municipal supply. It is a problem in a city with three-hour evening power cuts or a two-hour morning supply window.

A wall-mounted unit with a 7-10 litre tank is, in effect, a small buffer against both. If you have ever filled a bucket because the water was about to go off, you already understand why the tank matters more than the counter space.

• A 30-35 mm hole cut through the countertop for the dispensing faucet — irreversible, and worth checking against your counter material first. Granite and quartz need a core drill and a competent installer.
• A power point inside the cabinet, ideally on an RCD-protected circuit. Cabinet interiors are damp environments; an extension lead coiled next to a drain trap is not acceptable.
• A tee off the cold supply with its own isolation valve, so the purifier can be shut off without shutting the kitchen.
• A drain connection for the RO reject line, usually a saddle clamp on the waste pipe.
• A leak tray under the unit. Ask for one even if it is not standard — a slow leak inside a closed cabinet destroys a carcass long before anyone notices.

Every filter change on an under-sink unit begins with emptying the cabinet. Technicians work faster and more carefully on a wall-mounted unit at chest height than kneeling in a cupboard with a torch, and some AMC providers quietly price under-sink service higher for exactly that reason.

Over a ten-year life, that is roughly twenty service visits. It is worth asking your provider whether their AMC rate differs by mounting type before you commit.