Perth water ranked worst Australian city for washing skin and hair because of hard minerals

Perth has been ranked the worst Australian capital for skin and hair health — with experts blaming the water coming out of the tap.

A new national analysis found that Perth has some of the hardest and most variable tap water in the country, with residents in parts of the northern suburbs washing in water containing more than 200mg/L of minerals.

The PhycoHealth Tap Water Skin & Hair Health Index ranked Australia’s capital cities based primarily on water hardness, alongside disinfectant type and water source.

Perth finished last, behind Adelaide, while Hobart topped the rankings.

The results don’t mean Perth’s water is unsafe to drink — all of the capital cities included in the study meet Australian drinking water standards.

But researchers say the amount of calcium and magnesium in the water can affect how it interacts with skin and hair.

Perth’s city-wide average hardness was estimated at about 96mg/L, putting it in the moderately hard category.

But the figure masks huge differences across the metropolitan area.

Water hardness ranged from about 29mg/L in some areas to 228mg/L at Two Rocks, with Yanchep measuring about 204mg/L.

It means some Perth residents are dealing with water more than seven times harder than others in the same city.

PhycoHealth founder and marine scientist Pia Winberg said the differences could be even more striking between nearby areas.

“Earlier in my career, I worked in drinking water testing for local government, tracing water from its source through treatment and into the tap,” Dr Winberg said.

“One thing that stays with me is how different water can be across regions, even from within the same State, and in some cases differences can be found at two ends of the same street.”

The study found that Perth had the widest variation in water hardness of any Australian capital.

Researchers said harder water could leave microscopic mineral deposits on the skin and hair, while also making soaps and shampoos harder to rinse away.

For some people, particularly those with sensitive skin, the daily exposure could contribute to dryness or irritation.

Hair can also be left feeling coated, rough or dull, particularly for people with fine, coloured or chemically treated hair.

Perth’s complex water supply is partly responsible for the variation, with groundwater, desalinated seawater and surface water all contributing to the city’s supply.

The northern suburbs supplied by groundwater generally have the highest mineral levels, while some southern and Hills areas supplied by surface water have significantly softer water.

Dr Winberg said Australians often overlooked their tap water when trying to solve skin and hair problems.

“People often spend hundreds of dollars trying to solve dry skin or dull hair without ever considering what’s coming out of their showerhead,” she said.

“Australia has some of the safest drinking water in the world — but ‘safe’ doesn’t mean identical.”

Perth residents in harder-water areas are being advised to consider using a chelating shampoo about once a week to remove mineral deposits from hair.

A moisturiser containing ceramides or niacinamide after showering can also help support the skin barrier, according to the analysis.

Dr Winberg said a simple change to a hair and skincare routine could help those affected by Perth’s harder water.

“Once you know what’s coming out of your tap, protecting your skin and hair is straightforward,” she said.

“If you’re in Perth, a chelating shampoo once a week and a barrier-repair moisturiser with ceramides or niacinamide can make a real difference.”

Hobart was ranked Australia’s best capital for skin and hair, followed by Melbourne, Sydney, Canberra, Brisbane and Adelaide.

The study used publicly available water quality data from State water utilities and the Australian Drinking Water Guidelines.

The researchers stressed that the rankings related to potential skin and hair impacts — not the safety or drinkability of Perth or the nation’s water.