Best Under-Sink & Countertop Filtration (Sep 2026)

Measure the height under the sink and the space beside the drain. Most systems need 40 cm of clearance.

Carbon blocks handle chlorine, taste and sediment; reverse osmosis also removes dissolved solids like lead and nitrates.

Only for RO and some two-stage systems. Carbon blocks keep the existing faucet.

RO systems send two to four litres to drain per litre produced; tankless RO does better but costs more.

Multiply replacements by price. It is the number that decides whether a cheap system is actually cheap.

A carbon block is a one-hour DIY job with a wrench; RO needs a drain saddle and often a new faucet hole.