Hard water contains high levels of calcium and magnesium. Soft water contains very little of either. That single difference has a big effect on your skin, hair, cleaning products, and appliances.
In Australia, about 30% of households have hard water at the tap. Perth and Adelaide score highest. Melbourne and Sydney are mostly soft. Knowing the difference helps.
What Is Hard Water?
Hard water has a high mineral content. Calcium and magnesium dissolve into the water as it moves through rock underground. The more limestone or dolomite the water passes through, the harder it gets.
Australian Drinking Water Guidelines classify hardness like this:
- Soft: below 60 mg/L
- Moderately hard: 60-120 mg/L
- Hard: 120-200 mg/L
- Very hard: above 200 mg/L
Perth’s city-wide average is 96 mg/L. Northern suburbs reach 228 mg/L. Adelaide averages 97-103 mg/L. Both cities sit in the moderately hard to hard range.
Perth and Adelaide score highest because of their groundwater sources. Our article on what causes hard water explains the geology in detail.
What Is Soft Water?
Soft water has low mineral content. It typically has fewer than 60 mg/L of dissolved calcium and magnesium.
Melbourne averages around 31 mg/L. Sydney averages around 43 mg/L. Both cities draw from granite-based mountain catchments. Granite doesn’t dissolve into water the way limestone does. That keeps mineral levels low.
Rainwater is naturally soft. It starts with almost no dissolved minerals. It only picks up calcium and magnesium after it contacts rock and soil.
How They Look and Feel Different
Hard water looks clear in the glass. But it leaves white, chalky deposits when it dries. You see this on shower screens, taps, and kettles. These deposits are calcium carbonate. Hard water also reacts with soap to form a sticky scum. Soap doesn’t lather well. You use more product to get the same result.
Soft water also looks clear. When it dries, it leaves very little residue. Soap lathers freely in soft water. You need less detergent and shampoo.
Effects on Skin and Hair
Hard water and soft water feel different on the skin.
Hard water leaves a film on the skin after washing. It reacts with soap to form calcium soap deposits. Hard water can leave skin feeling dry or tight after a shower. Some people notice more scalp irritation. In Perth and Adelaide, hard water skin complaints are more common. Melbourne and Sydney residents notice fewer issues. The water hardness difference explains most of it.
Note: hard water is not a medical treatment for any skin condition. If you have eczema or a diagnosed skin condition, see a dermatologist. A shower filter is not a substitute for medical advice.
Soft water rinses cleanly. Many people find their hair feels softer after switching to soft water or filtered water. Hard water can leave a mineral residue on hair over time.
Effects on Appliances and Plumbing
Hard water damages appliances.
Calcium deposits build up inside kettles, coffee machines, washing machines, and dishwashers. This is called scale or limescale. It reduces heating efficiency and shortens appliance life.
Soft water causes very little scale. Appliances stay cleaner and last longer. Pipes stay clear.
Perth and Adelaide homeowners often use shower filters for the same reason. Appliances last longer when the water is filtered.
Effects on Cleaning
Hard water makes cleaning harder. Soap reacts with calcium to form scum. You need more product. Surfaces need more wiping.
Soft water cleans more efficiently. Less detergent. Less scrubbing. Glasses and dishes come out cleaner.
How to Tell Which Type You Have
There are a few quick ways to check at home.
Look at your kettle. A chalky white lining inside the kettle means hard water. Look at your shower screen. White spots and a stubborn mineral film are a sign too.
Try the soap test. Shake a few drops of pure liquid soap in a bottle of tap water. Clear water and lots of bubbles mean soft water. Cloudy water and poor lather mean hard water.
For a proper reading, use a test strip. They’re available at hardware stores and online. Read our how to test for hard water at home guide. It covers all methods and explains what the numbers mean.
Can You Change Hard Water to Soft Water?
Yes. There are several ways.
Water softeners use ion exchange to swap calcium and magnesium for sodium. They soften the whole house supply. They need regular maintenance and salt top-ups.
Shower filters take a targeted approach. They reduce calcium, magnesium, chlorine, and heavy metals at the shower head. No plumbing. No ongoing salt. Just a cartridge swap every 2-6 months.
For skin and hair, a shower filter is the most practical option. It works without plumbing changes. The POWERBOX™ 25-stage filter is built for Australian hard water. It costs $44.99 AUD. Shipping is free.
See the full range at POWERBOX™ hard water filters.