The best reverse osmosis water filters in Australia
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Reverse osmosis is the only common home filter that removes fluoride and dissolved solids. Under-sink and countertop RO systems sold in Australia compared, with the water-waste and mineral trade-offs explained.
Our picks at a glance
| Pick | Product | Stages | Install | Price* |
|---|---|---|---|---|
| Best value | Geekpure 5-stage under-sink reverse osmosis system, 75 GPD | 5 (sediment, 2 carbon, RO membrane, post carbon) | Plumbed with its own tap, licensed plumber | $234.99 |
| Best with remineralisation | iSpring RCC7AK 6-stage under-sink RO with alkaline remineralisation | 6 (adds alkaline remineraliser) | Plumbed with its own tap | $503.42 |
| Best for renters | Waterdrop C1S countertop reverse osmosis, no plumbing | 6-stage RO | None, fill the tank and plug in | $424.15 |
| Best in-store | Philips 75 GPD reverse osmosis tap water station with remineraliser | — | Plumbed, licensed plumber | $499 |
Reverse osmosis is the step beyond carbon. If you want fluoride, dissolved solids, most metals and most chemicals out of your drinking water, this is the technology, and it is now affordable.
How it works
Pressure pushes water through a semi-permeable membrane. Water molecules pass; dissolved salts, fluoride, metals and most larger molecules do not, and are flushed to the drain. Pre-filters protect the membrane from sediment and chlorine, and a post-carbon polishes taste. Under-sink systems store the slow output in a small pressurised tank feeding a dedicated tap. Countertop units use a pump and a reservoir instead of plumbing.
The trade-offs, honestly
RO is slow, it wastes water, it strips minerals, and it takes space. Tank systems fill most of an under-sink cupboard. The reject water is clean enough for the garden, and plumbing it there is worth asking the plumber about. Remineralising stages, as on the iSpring and Philips units, put calcium and magnesium back for taste.
Installation
Under-sink RO is plumbing: cold feed, drain connection and a new tap. Licensed plumber, WaterMark-certified fittings. Countertop RO plugs into a power point and that is all.
The picks
The Geekpure 5-stage is the cheapest complete system we found and uses standard cartridges. Pay more for the iSpring RCC7AK if flat-tasting water would bother you. Renters should buy the Waterdrop C1S countertop. If you want to buy in a shop with easy returns, the Philips RO tap water station at Bunnings includes a remineraliser.
The picks in detail
Geekpure 5-stage under-sink reverse osmosis system, 75 GPD
$234.99 at amazon.com.au · checked 12 Sep 2026
A complete five-stage under-sink system with tank and tap for under $240.
- Stages: 5 (sediment, 2 carbon, RO membrane, post carbon)
- Output: 75 gallons (about 280 L) per day
- Tank: Pressurised storage tank
- Install: Plumbed with its own tap, licensed plumber
Pros
- Cheapest full RO system we found
- Removes fluoride and most dissolved solids, which carbon cannot
- Standard cartridges
Cons
- Wastes several litres of water per litre produced
- Takes most of the under-sink cupboard
- Strips minerals; some people prefer a remineraliser
iSpring RCC7AK 6-stage under-sink RO with alkaline remineralisation
$503.42 at amazon.com.au · checked 12 Sep 2026
Six stages, the last one putting minerals back for taste.
- Stages: 6 (adds alkaline remineraliser)
- Output: 75 GPD
- Tank: Pressurised storage tank
- Install: Plumbed with its own tap
Pros
- Puts minerals back after RO, which fixes the flat taste
- Very widely reviewed
Cons
- Twice the price of the Geekpure
- Same water-waste and space issues as any tank RO
Waterdrop C1S countertop reverse osmosis, no plumbing
$424.15 at amazon.com.au · checked 12 Sep 2026
No plumbing at all, and a low waste ratio for an RO unit.
- Install: None, fill the tank and plug in
- Stages: 6-stage RO
- Certification: NSF/ANSI 372 lead-free (listing)
- Waste ratio: About 3:1 pure to drain (listing)
Pros
- Reverse osmosis for renters, no plumber
- Low water waste for an RO unit
Cons
- You refill a tank by hand
- Needs power and bench space
Philips 75 GPD reverse osmosis tap water station with remineraliser
$499 at bunnings.com.au · checked 12 Sep 2026
RO with a remineraliser from Bunnings, with Bunnings returns.
- Output: 75 GPD
- Remineraliser: Yes
- Install: Plumbed, licensed plumber
- Stockist: Bunnings
Pros
- RO with remineralisation from a brand you can buy in-store
- Bunnings warranty and returns
Cons
- Dearer than the Amazon RO units
Frequently asked questions
Does reverse osmosis remove fluoride?
Yes. RO membranes reject most dissolved ions, and fluoride removal in the 85 to 95 percent range is typical for a well-maintained system. It is the standard home method.
How much water does reverse osmosis waste?
Traditional tank systems send two to four litres to the drain for every litre produced. Newer countertop units claim around 3:1 the other way. On a water-restricted supply this matters; the waste can be run to a garden.
Is reverse osmosis water bad for you?
RO water is low in minerals, and some people find it tastes flat. Mineral intake from water is small compared with food, but if the taste bothers you choose a system with a remineralising stage.
How often do RO filters need changing?
Pre-filters every six to twelve months, the membrane every two to three years, the post-carbon yearly. A TDS meter for twenty dollars tells you when the membrane is tired.