What is in Perth's tap water, and which filter fixes what
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Philips 75 GPD reverse osmosis tap water station with remineraliser
WaterMark-listed reverse osmosis with a remineraliser: the one home filter that deals with Perth's dissolved minerals at the kitchen tap.
$499 at Bunnings, checked 9 Nov 2026 · Amazon's price is on its page
Paid links: we may earn a commission. As an Amazon Associate I earn from qualifying purchases. It doesn't change which product is here.
Perth has the hardest tap water of the capitals and uses free chlorine. What that means for taste, scale and showers, and which filters address each problem honestly.
Our picks at a glance
| Product | Hardness and fluoridePhilips 75 GPD reverse osmosis tap water station with remineraliser $499 at Bunnings | ShowerPhilips 3-stage shower filter, KDF and double mesh Price at the retailer | Whole houseStefani 4.5 x 20 inch twin whole-of-house lead-free system $492 at Bunnings |
|---|---|---|---|
| Cartridge | — | — | — |
| Install | Plumbed, licensed plumber | — | On the mains inlet, licensed plumber |
| Why it's here | WaterMark-listed reverse osmosis with a remineraliser: the one home filter that deals with Perth's dissolved minerals at the kitchen tap. | Perth uses free chlorine, so KDF works; nothing on a shower arm softens water. | WaterMark-listed sediment and carbon for every tap, in big 20 inch housings; pair with a softener if scale is the problem. |
| Watch out for | A tank system, so it fills the cupboard and sends water to the drain like any tank RO | Cartridges need replacing every few months | Big and heavy; needs a solid wall and room to swing a housing wrench |
| Buy | Today's price on Amazon$499 at Bunnings | Today's price on Amazon | $492 at Bunnings |
WaterMark-listed reverse osmosis with a remineraliser: the one home filter that deals with Perth's dissolved minerals at the kitchen tap.
WaterMark-listed reverse osmosis with a remineraliser: the one home filter that deals with…
Watch out: A tank system, so it fills the cupboard and sends water to the drain like any tank RO
- Install: Plumbed, licensed plumber
$499 at Bunnings, checked 9 Nov 2026 · Amazon's price is on its page
Perth uses free chlorine, so KDF works; nothing on a shower arm softens water.
Perth uses free chlorine, so KDF works; nothing on a shower arm softens water.
Watch out: Cartridges need replacing every few months
Price at the retailer
WaterMark-listed sediment and carbon for every tap, in big 20 inch housings; pair with a softener if scale is the problem.
WaterMark-listed sediment and carbon for every tap, in big 20 inch housings; pair with a…
Watch out: Big and heavy; needs a solid wall and room to swing a housing wrench
- Install: On the mains inlet, licensed plumber
$492 at Bunnings · checked 9 Nov 2026
How we picked: We picked these 3 from the water filters sold in Australia, judged on cartridge, install and price, using maker specs, Australian retailer prices and owner reports. We haven't tested them hands-on yet, and maker claims are labelled as theirs. Commission never puts a worse product ahead of a better one, but between equal products or shops, one that pays us can go first. Full method.
Perth has the hardest water of the capitals, drawn from groundwater, desalination and dams by the Water Corporation, and it is chlorinated rather than chloraminated. That combination makes it easy to filter for taste and hard to fix for scale.
The three things that matter
Hard water. Zones range from around 100 to over 200 milligrams per litre. Kettles, coffee machines and shower screens scale fast. This is the main reason Perth people buy filters, and most of the filters they buy do not address it.
Free chlorine. The easy disinfectant. Any carbon or KDF filter removes it.
Fluoride. Present; reverse osmosis removes it.
What to buy in Perth
- Scale at the kitchen tap and fluoride: a WaterMark-listed reverse osmosis system, ideally with a remineraliser for taste, such as the Philips 75 GPD station. The cheapest online kits (Geekpure, iSpring) aren’t on the WaterMark register, so a licensed plumber can’t install them.
- Scale everywhere: a whole-house softener from a plumber is the only real fix. A whole-house filter handles sediment and chlorine but not hardness.
- Shower: the Philips KDF filter for chlorine; read the hard water shower filter guide before expecting anything more.
- Your own water: test your own tap water with hardness strips or a TDS meter before you buy. The test kit guide covers what a home kit can and can’t tell you, and when to use a NATA-accredited lab instead.
Sources: Water Corporation water quality reporting; Australian Drinking Water Guidelines (NHMRC). Hardness varies by zone; check yours.
Where to buy our picks
- Philips 75 GPD reverse osmosis tap water station with remineraliserSee today's price on Amazon
- Philips 3-stage shower filter, KDF and double meshSee today's price on Amazon
- Stefani 4.5 x 20 inch twin whole-of-house lead-free system$492 at Bunnings
Paid links: we may earn a commission. As an Amazon Associate I earn from qualifying purchases. Prices change; the shop's page is the final word.
The picks in detail
Tap a pick for its full specs, pros and cons and every shop.
Hardness and fluoridePhilips 75 GPD reverse osmosis tap water station with remineraliser
$499 at Bunnings · checked 9 Nov 2026Specs, pros and cons, all 2 shops
WaterMark-listed reverse osmosis with a remineraliser: the one home filter that deals with Perth's dissolved minerals at the kitchen tap.
- Output: 75 GPD
- Remineraliser: Yes
- Install: Plumbed, licensed plumber
- Certification: WaterMark, licence 060214
- WaterMark: Yes, licence 060214
- Yearly running cost: About $215 to $335 at Philips RRP (AUT515, AUT514, AUT521 sets)
Pros
- RO with remineralisation from a brand you can buy in-store
- Bunnings warranty and returns
Cons
- A tank system, so it fills the cupboard and sends water to the drain like any tank RO
Paid links: we may earn a commission. As an Amazon Associate I earn from qualifying purchases. Price checked 9 Nov 2026.
ShowerPhilips 3-stage shower filter, KDF and double mesh
See retailer · checked 9 Nov 2026Specs, pros and cons and where to buy
Perth uses free chlorine, so KDF works; nothing on a shower arm softens water.
- Media: KDF plus mesh stages
- Fits: Standard shower arm thread
- Reduces: Chlorine (manufacturer claim)
- Cartridge life: 4-6 months or 50,000 L (Philips claim)
Pros
- Sold and shipped by Amazon Australia
- KDF is the media with real evidence for chlorine reduction
- Fits before your existing shower head
Cons
- Cartridges need replacing every few months
- Slight reduction in flow
Paid links: we may earn a commission. As an Amazon Associate I earn from qualifying purchases. Price checked 9 Nov 2026.
Whole houseStefani 4.5 x 20 inch twin whole-of-house lead-free system
$492 at Bunnings · checked 9 Nov 2026Specs, pros and cons and where to buy
WaterMark-listed sediment and carbon for every tap, in big 20 inch housings; pair with a softener if scale is the problem.
- Stages: 2 (5 micron sediment, 5 micron carbon block) in 4.5 x 20 inch big-blue housings
- Install: On the mains inlet, licensed plumber
- Flow rate: Not stated on the listing
- Filter life: Not stated on the listing
- Certification: WaterMark certified, lead-free (listing)
- WaterMark: Yes, licence 022200 (model WHF-T20-LF)
- Fitting: 4.5 x 20 inch big-blue housings on the mains or tank inlet (port size not stated on the listing)
Pros
- 20 inch housings double cartridge life compared with the 10 inch twin
- Standard big-blue size, so catalytic carbon or softening resin cartridges fit the second housing
- WaterMark certified and sold at Bunnings with cartridges on the shelf
Cons
- Big and heavy; needs a solid wall and room to swing a housing wrench
- Stefani 20 inch cartridges cost $64 to $135 each at Bunnings
Paid links: we may earn a commission. Price checked 9 Nov 2026.
Frequently asked questions
Why is Perth water so hard?
Much of Perth's supply is groundwater and desalinated seawater blended with dam water, and the groundwater carries dissolved calcium and magnesium. Hardness runs from around 100 to over 200 milligrams per litre depending on the zone, which is the hardest of the capitals.
Does Perth use chlorine or chloramine?
Free chlorine, which is the easier one to filter. Standard carbon and KDF filters work well in Perth.
What fixes scale in Perth?
A whole-house ion-exchange softener, installed by a plumber. Reverse osmosis fixes it at the kitchen tap only. Shower filters do not soften water, whatever the packaging says.