The best alkaline water filters in Australia: an RO system with a remineraliser, and what it actually changes

“Alkaline water filter” is one of the most searched phrases in this category and one of the most loosely used. Here is what the products do, what they do not, and which ones are worth money.

Questions to ask before buying an alkaline water filter in Australia

• What pH is my water already? The national guidelines say drinking water should be between 6.5 and 8.5, and that range is set to limit corrosion and scale in pipes. Ask your utility for your figure.
• Will it make me healthier? We don’t make that claim. The guideline pH range is about pipes and taste, and the maker’s health wording isn’t evidence.
• Am I fixing flat-tasting RO water? That’s the job an alkaline stage does well, so buy it as a remineraliser on an RO system.
• Will a licensed plumber fit it? Only if it’s certified where WaterMark applies. WaterMark says a licensed plumber is not permitted to install a product of a listed type that isn’t certified, even if it was legal to sell. Search the WaterMark register by model before you pay.
• What happens if it fails after the warranty? The ACCC says the consumer guarantee of acceptable quality usually still applies after a warranty expires.

What alkaline means here

pH measures how acidic or alkaline water is. Seven is neutral. Australian tap water is held between 6.5 and 9.2 under the Australian Drinking Water Guidelines; Hunter Water’s published median, for example, is 7.3 to 7.5 across its plants and Sydney Water lists pH among its routine tests. Reverse osmosis water, having lost its dissolved minerals, drifts slightly acidic, often 5.5 to 6.5.

An alkaline, remineralising or pH-plus filter contains mineral media that dissolves a little into the water passing over it. The result, according to the makers, is water at about 7.5 to 8.5 with some calcium and magnesium added back. That is the entire mechanism. It filters nothing out: Geekpure’s own listing says its alkaline cartridge “is not designed to remove fluoride nor chlorine”, which is more candour than most.

We credit alkaline filters with one thing: making reverse osmosis water taste less flat. Claims beyond that are outside what we can verify, and we leave them out.

Three ways to get it

Prices from Bunnings, checked 21 October 2026; Amazon AU prices change daily, so check them there.

RO systems with a sixth stage

If you are buying reverse osmosis anyway, a remineralising stage is the sensible way to get alkaline water, because the RO has already taken the minerals out and the stage is just putting a measured amount back.

A plumbed RO system has to be on the WaterMark register: WaterMark’s own consumer page says a licensed plumber isn’t permitted to install a water filter that isn’t certified. The Philips 75 GPD station at Bunnings, $499, is WaterMark-listed, includes a remineraliser and is the one you can return to a shop. The Philips 400 GPD ($699 at Bunnings) is the tankless version, also WaterMark-listed with a remineraliser. The best-known six-stage kits on Amazon AU, the iSpring RCC7AK and Geekpure six-stage, aren’t on the WaterMark register (see the competition below). The reverse osmosis guide compares the systems in detail, and the worth-it guide covers whether RO is for you at all.

Adding a cartridge to what you own

A plain RO or under-sink system can be made alkaline with one inline cartridge after the last stage. The Stefani inline alkaline balancer at $29.65 from Bunnings fits Stefani under-sink, full-flow and RO systems, Stefani says. It goes into the water line of a plumbed system, so have your plumber fit it, ideally when the system goes in or at a service.

One note: the Bunnings listing for the Stefani cartridge makes health claims about pH and the body. We do not repeat them. Buy it to change taste.

Alkaline jugs

A jug cannot remineralise RO water because it is not fed RO water; it adds minerals to tap water that already has them. The pH rise is real but the taste change on soft Melbourne or Sydney water is modest. The Santevia MINA is the jug we would choose because its maker gives a number, up to 2 pH units, rather than a mood. The Hskyhan jugs are the budget option with “7 stage” marketing we would ignore. Both reduce chlorine like any carbon jug; their lead and fluoride claims carry no certification we could find.

What alkaline filters do not do

• They do not remove fluoride, chlorine, chloramine, lead or anything else. That is the job of the stages before them.
• They do not soften water. Hardness is calcium and magnesium; an alkaline filter adds those. See the softener guide.
• They do not keep working indefinitely. The media dissolves, which is how it works, and the pH rise fades over months. Change on schedule.

The picks

Buying RO: the Philips 75 GPD station, WaterMark-listed with a remineraliser and Bunnings returns, or the tankless Philips 400 GPD. Already own a Stefani system: the Stefani balancer, fitted by your plumber. Renting: the Santevia MINA.

The competition

We checked the WaterMark register on 21 October 2026. None of these is on it, so a licensed plumber can’t install them.

• iSpring RCC7AK (Amazon Australia). Six stages with the alkaline stage last; the best-known RO kit on Amazon AU.
• Geekpure six-stage (Amazon Australia). Five RO stages plus an alkaline cartridge the listing says lifts pH to 7.5 to 8.5, at a 1:2 pure-to-waste ratio and with no system certification.
• Geekpure 10 inch alkaline kit (Amazon Australia). An inline add-on with fittings for quarter-inch and 3/8 inch tube; it lists WQA as its external testing certification.

The one trap

Buying an alkaline filter to fix water that tastes bad. Bad taste is chlorine, chloramine, organics or hardness, and an alkaline cartridge removes none of them; it adds a mineral note on top. Fix the taste first with the right carbon filter, which our how to choose guide walks through, and add pH only if the water then tastes flat. On tap water that is rarely the case; on reverse osmosis water it often is.