Stage counts and brand names hide a simple question: what does each technology actually take out of your water? Here is the plain comparison.
RO, UF and UV do different jobs. Reverse osmosis (RO) pushes water through a very fine membrane and removes dissolved substances as well as particles and bacteria, but it sends part of the water to the drain and strips minerals too. Ultrafiltration (UF) is a coarser membrane that removes particles and microbes but lets dissolved salts through, with no waste water. UV does not filter at all: it inactivates bacteria and viruses in water that is already clear. “Alkaline” ionisers raise the pH, but there is no evidence that drinking alkaline water brings health benefits. Choose by what is actually in your water, and plan the plumbing, drain and power before the kitchen is finished.
Water purifiers are sold on the number of stages and the names of technologies. The more useful question is what you are trying to fix: sediment and a brown tinge after a burst main, a chlorine taste, a worry about germs from an old roof tank, or a concern about dissolved substances. Each technology deals with some of these and not others. Our water purifier servicing guide covers the unit types from the maintenance side; this page compares what each technology actually does.
If the problem is dirty water throughout the house, a drinking filter at one tap is the wrong tool. Our whole-house filtration guide covers the outdoor master filter that protects every outlet.
| RO (reverse osmosis) | UF (ultrafiltration) | UV | Alkaline ioniser | |
|---|---|---|---|---|
| How it works | Pressure pushes water through a very fine membrane | A hollow-fibre membrane strains out particles | Ultraviolet light inactivates microbes | Electrolysis splits water into acidic and alkaline streams |
| Removes particles and bacteria | Yes | Yes | No removal; inactivates microbes | Not its purpose |
| Removes dissolved salts | Yes | No | No | No |
| Waste water | Yes, a reject stream to the drain | No | No | An acidic stream |
| Needs power | Usually, for the pump | Usually not | Yes | Yes |
| Main caution | Strips minerals; needs a drain line | Dissolved substances pass through | Water must be clear first | Health claims not supported by evidence |
Wikipedia describes RO as a purification process that uses a semi-permeable membrane and pressure to separate water from other substances, removing dissolved and suspended substances as well as bacteria. In the membrane hierarchy it is the finest step, removing particles larger than about 0.2 nanometres, far smaller than ultrafiltration.
That finesse has costs you should plan for. The membrane needs pre-filters to protect it, a reject stream carries the concentrated impurities to the drain, and the membrane removes the minerals as well as the contaminants. Under the sink, an RO unit needs a drain connection for the waste line and, usually, a power point for its pump. The servicing guide explains why skipping pre-filter changes ends up costing a membrane.
Ultrafiltration is a coarser membrane. The same Wikipedia comparison puts UF at removing particles of roughly 3 nanometres or larger, which is fine enough to strain out sediment, bacteria and most microbes, but not dissolved salts or minerals. It usually runs on mains pressure without a pump and sends no water to the drain.
UF suits water that is treated at source but picks up sediment and microbes on the way, through old pipes or a roof tank. It does not change the taste of dissolved minerals, and membranes can foul, so the pre-filter and the flushing routine matter.
UV purification does not remove anything. Ultraviolet germicidal irradiation, in Wikipedia’s words, can inactivate microorganisms including bacteria, viruses, fungi and moulds. It is usually added as a final stage after filtration, because it works on water that is already clear, and the lamp needs power and periodic replacement. A UV stage on its own does nothing for sediment, taste or dissolved substances.
Most purifiers, whatever the headline technology, start with a sediment filter and a carbon stage. The servicing guide describes a countertop or faucet filter as usually sediment plus carbon in one cartridge. These stages catch particles and improve taste and smell, and in an RO system they protect the membrane. Changing them on time matters more than the stage count on the box.
Water ionisers use electrolysis to split incoming water into acidic and alkaline streams and are sold on health claims. Wikipedia’s summary is direct: there is no empirical evidence to support those claims, drinking ionised or alkaline water does not alter the body’s pH, and cancer societies have rejected claims of a link to cancer prevention. If you like the taste, that is a preference; it is not a reason to pay a premium for health.
| Your problem | Usually the right fix | Notes |
|---|---|---|
| Brown or cloudy water in every tap | Whole-house outdoor master filter | A drinking filter only treats one tap |
| Chlorine taste or smell | Carbon stage at the kitchen tap | Simple, low maintenance |
| Worry about germs from old pipes or a roof tank | UF, or filtration plus UV | Clean the tank as well |
| Concern about dissolved substances | RO | Plan the drain line; minerals are removed too |
| Hard water and scale on kettles | Softener or anti-scale at the inlet | Not a drinking-filter job |
Our kitchen sink and tap guide covers the separate filtered-water tap on the counter.
ClickBina’s filtration guide publishes these indicative 2026 Klang Valley figures. The purifier unit and its cartridges are priced by brand and stage count, so they are not included:
| Work | Indicative price | Notes |
|---|---|---|
| Under-sink drinking filter install | RM150 – RM500 | Single kitchen tap, labour only |
| Outdoor master filter, supply & install | RM1,500 – RM3,500 | Whole house; sand and carbon tank |
| Annual media change / servicing (master filter) | RM200 – RM600 | Media, backwash check, bypass and joint test |
WhatsApp us your job details for a quote — we reply within the hour.
💬 WhatsApp for a quoteA purifier is easiest to fit neatly when the kitchen is being built or refurbished, with the tap hole, drain and power planned in. ClickBina is an experienced KL & Selangor contractor that handles whole-house refurbishment and coordinates the trades on one job. WhatsApp us your job details for a quote: the type of unit, whether it is already bought, and the space under your sink. We reply within the hour, the price we agree is a flat price with no hidden charges, and a site visit is RM150, waived if you go ahead.
How we estimated prices: every RM figure is quoted unchanged from the ClickBina guide named above; they are typical Klang Valley ranges for 2026, not fixed rates.
WhatsApp us your job details for a quote — we reply within the hour.
💬 WhatsApp for a quoteTell us what you need — we reply within the hour.