Shower filters for coloured or treated hair: the honest version

Hairdressers tell clients with fresh colour to keep it away from chlorine, and clients go looking for a shower filter. Here is what one can do for you, and the quite long list of things it cannot.

Why chlorine comes up at all

Chlorine is an oxidiser. Permanent hair colour is a set of dye molecules locked into the hair shaft by an oxidising developer, and further oxidation is one of the things that shifts it. That is the chemistry behind the salon advice to wet hair with clean water before a swim and rinse straight after. Pools are the real exposure: free chlorine of a few milligrams per litre for an hour.

Tap water carries less and for less time. The utilities publish the figures: Icon Water’s Canberra network averages 1.05 mg/L total chlorine (2024–25 report), the City of Gold Coast targets 0.2 to 1.8 mg/L, Hunter Water’s plants run a median of 1.3 to 1.9 mg/L, and Power and Water keeps Darwin’s at a minimum of 0.6 mg/L. A ten-minute shower at those levels is a small fraction of a swim. It is also hot, which releases chlorine into the air, and some people simply dislike that. Reducing it is a reasonable thing to want.

What a shower filter can do

A KDF filter converts free chlorine to chloride as water passes over copper-zinc granules. A vitamin C filter neutralises chlorine and chloramine with ascorbic acid. Both bring the chlorine in the stream to near zero while the cartridge is fresh, and a pool test strip proves it in thirty seconds. That is the product’s one verified function. The do shower filters work guide goes through the evidence in detail.

What it cannot do

Protect your colour. We cannot find independent evidence that reducing tap-water chlorine extends hair colour, and the variables hairdressers list first are heat styling, sun, wash frequency and shampoo. A filter removes one small variable. If your colour lasts longer afterwards, good; nobody could have promised it.

Soften water. Mineral residue from hard water is a real complaint in Adelaide and Perth, where hardness runs 100 to 200 mg/L and above, and it is not something a shower filter touches. The hard water shower filter guide explains why, and the softener guide covers what does.

Remove fluoride or heavy metals at shower flow rates. See the fluoride guide.

Anything described as repair, nourishment or treatment. Filters remove things from water. They do not add anything to hair.

Chlorine or chloramine: check first

The right media depends on your utility. Chlorine: Sydney, Perth, Canberra, Hobart, Darwin, Newcastle, Gold Coast, Sunshine Coast and most of Melbourne. Chloramine: Brisbane, Ipswich, Logan and Moreton Bay, metropolitan Adelaide and Melbourne’s west. On chloramine, a KDF filter does little, so a Brisbane buyer who fits the Philips unit will conclude shower filters do not work. They do; that one was the wrong media. The vitamin C versus KDF guide and the city comparison make the choice quick.

The products

Bunnings prices checked 21 October 2026; Amazon prices change daily, so the buttons show today’s. The marketplace filters on Bunnings and Amazon AU often lead with hair and skin promises and a stage count; the stage count is padding and the promises are untestable.

Marketing to ignore

• “Softens water for silky hair”: no shower filter softens water.
• “Removes fluoride”: not at shower flow.
• “Infuses vitamins into hair”: vitamin C in these filters reacts with chlorine in the water and is gone; it is a dechlorinator, not a conditioner.
• “Aromatherapy”: scented cartridges exist (Quoss sells them as Aroma Sense); the scent is a preference, not a function.
• Any number of stages above three.

The picks

On chlorinated water, the Philips KDF filter. On chloraminated water, the Quoss universal filter with vitamin C refills from Bunnings (a Special Order) or Amazon, or Sonaki cartridges if you have a Sonaki housing. Fit it before your existing shower head, test with a strip, and write the date on it. The shower filter guide has the broader comparison and the cartridge replacement guide the schedule.

The one trap

Buying a filter because the listing talks about hair. The filters that lead with hair and skin claims are, in our reading, the ones with the least to say about chlorine reduction, the vaguest media descriptions and the highest stage counts. The filters that lead with KDF or vitamin C and a cartridge life are the ones that reduce chlorine. Buy the second kind and let your hairdresser judge the result.