Hard water carries a lot of dissolved calcium and magnesium. Soft water carries almost none. That one difference decides how your soap lathers and how your skin feels after a shower. It also decides how much scale builds up in your kettle. This guide puts hard water vs soft water side by side for an Australian home. Every figure names its source and its year.
Australia measures hardness in mg/L (as calcium carbonate). Your water retailer publishes a figure for your supply zone, not for your street.
What is hard water?
Hard water holds a lot of dissolved calcium and magnesium. Rain picks up those minerals as it soaks through rock and soil. Australia measures hardness in mg/L, as calcium carbonate. The national guidelines treat anything over 200 mg/L as a scaling risk. Hard water is still safe to drink.
The minerals come from the ground, not from the treatment plant. Limestone and dolomite give up the most calcium. Our geology guide, what is hard water, shows where the minerals come from.
The Australian Drinking Water Guidelines set four bands.
| Hardness (mg/L as calcium carbonate) | What the guidelines call it |
|---|---|
| Under 60 | Soft, but possibly corrosive |
| 60 to 200 | Good quality |
| 200 to 500 | Increasing scaling problems |
| Over 500 | Severe scaling |
The NHMRC sets 200 mg/L to keep scale out of hot water systems. It’s an aesthetic guideline. It’s not a health limit.
Many water websites use a finer scale. They call 60-120 mg/L moderately hard and 120-180 mg/L hard. That’s a common industry scale. The Australian guidelines never use those words, so we label them when we use them.
What is soft water?
Soft water holds very little calcium and magnesium. Sydney Water calls anything under 60 mg/L soft. Rain is soft when it falls. It only turns hard after it meets limestone or other mineral rock. Soft water lathers easily, so you use less soap and less detergent.
Catchment type does most of the work. Water stored in a sealed upland reservoir picks up few minerals on the way. Water drawn from a groundwater bore sits in rock for years and picks up plenty.
Soft water isn’t a pure win. The same guidelines flag water under 60 mg/L as possibly corrosive to pipes and fittings.
Is Australian tap water hard or soft?
Both, and your suburb decides which. Perth’s northern suburbs hold the hardest published figures. Two Rocks averaged 228 mg/L in 2024-25. Sydney sits near 57 mg/L. Melbourne’s storages ran 9 to 38. Canberra is soft too, at about 43. Adelaide sits in the middle, near 97.
| Place | Hardness (mg/L as calcium carbonate) | Band | Source and year |
|---|---|---|---|
| Two Rocks, Perth | 228 average | Increasing scaling | Water Corporation’s 2024-25 Perth aesthetic tables |
| Dwellingup, Perth region | 29 average | Soft | Water Corporation, 2024-25 |
| Adelaide metro | about 97 | Good quality | WaterScore, from SA Water data, Nov 2025 |
| Greater Sydney | about 57 | Soft | Sydney Water, checked Sep 2026 |
| Melbourne storages | 9 to 38 | Soft | Melbourne Water’s salinity table, July 2026 |
| Canberra | about 43 | Soft | Icon Water, checked Sep 2026 |
Perth proves why a city average tells you little. The same network runs from 29 mg/L to 228 mg/L. Two houses in one state can sit in different bands. Our national guide, does Australia have hard water, breaks it down city by city.
Hard water vs soft water at a glance
| What you notice | Hard water | Soft water |
|---|---|---|
| Calcium and magnesium | High | Low |
| Soap lather | Poor, forms scum | Free and quick |
| Detergent you use | More | Less |
| Glass and taps | White spots and film | Few marks |
| Kettle and element | Scale builds up | Stays clean |
| Skin after a shower | Can feel tight or filmy | Feels smoother |
| Pipes | Scale narrows them | Can corrode if very soft |
| Safe to drink | Yes | Yes |
How do hard and soft water feel on skin and hair?
Hard water leaves a film after you wash. Calcium reacts with soap and forms a sticky residue. Some people notice tight or dry skin after a shower. Soft water rinses clean, so skin feels smoother and hair feels lighter. The feel changes. Your skin health may not.
The film is soap scum, not mineral dust. Your soap reacts with the calcium and the product stays on the skin. That’s why the same body wash behaves differently in Perth and in Melbourne.
Hair picks up the same residue. Long hair holds more of it, because there’s more surface for the scum to sit on.
A shower filter is not a medical treatment for eczema or any skin condition. If you have a diagnosed skin condition, consult a dermatologist.
Does hard water damage appliances?
Yes, over time. Hard water drops limescale wherever it heats or dries. Scale coats the element in your kettle, washing machine and hot water system. Dishwashers block up at the spray arms and leave white spots. SA Water names scaling on appliances and taps as the problem.
Limescale is the chalky white crust hard water leaves behind. Heat pushes the calcium out of the water and onto the nearest surface. The hotter the water, the faster the crust grows.
Kettles. Your kettle shows it first. You see a white lining, flakes in your tea and a rough coating on the element. Vinegar or a shop descaler takes it off. In a hard water suburb it comes back quickly.
Washing machines. Scale settles in the drum, the pump and the element. Soap also performs badly, so you tip in more detergent for the same wash. Clothes can come out stiffer over time.
Dishwashers. Scale blocks the spray jets and dulls your glassware. Many dishwashers carry a salt reservoir for exactly this reason. The salt softens the water before it enters the machine. In a hard water area you top it up often.
Hot water systems. Heat drives the reaction, so scale keeps forming inside the tank. It sits between the element and the water. Descaling one is a plumber’s job, not a kitchen job.
Icon Water puts the point plainly. Hard water is more likely to cause scaling. Appliance makers print hardness guidance in their manuals, because hardness changes how their machines perform.
What it costs. No Australian water utility publishes a dollar figure for scale damage, so we don’t give one. We found no Australian data on shortened appliance life either. The costs you can count are extra detergent and regular descaling.
Descaling and dishwasher salt are upkeep, not a fix. The scale returns while the supply stays hard.
Which is better for your home, hard water or soft water?
Soft water is easier on your appliances, your soap bill and your skin. It isn’t perfect. The national guidelines warn that water under 60 mg/L can corrode pipes. Hard water is safe to drink and costs you nothing to keep. The real answer depends on your number.
Under 60 mg/L, there’s little to fix. Between 60 and 200 mg/L, you’ll see marks on glass and a slow crust in the kettle. Over 200 mg/L, scale becomes a regular job.
Most Australian homes sit in the middle band. That’s where hard water treatment is a choice rather than a need. Treat the outlet that bothers you, or treat the whole house, or live with it.
How do you tell which one you have?
Look in your kettle first. A chalky white lining means hard water. Then try the soap test. Shake pure liquid soap in a bottle of tap water. Lots of bubbles means soft. Cloudy water with poor lather means hard. A test strip gives you the number.
Your shower screen tells the same story. White spots that resist a normal wipe mean calcium.
You can turn the guess into a figure with a hard water test kit. Our testing guide walks through the strip, the soap test and the supplier lookup.
Your retailer holds the official number. SA Water’s postcode lookup takes a postcode or suburb and returns your water profile. SA Water also says plainly that more than 200 mg/L counts as hard water.
Can you change hard water into soft water?
Yes, with a water softener. It swaps calcium and magnesium for sodium across the whole house. It needs plumbing work and regular salt. A shower filter is the smaller option. It treats one outlet only, and it reduces calcium and magnesium rather than removing them.
A softener runs on ion exchange. Resin beads hold sodium and trade it for the calcium and magnesium in your supply. The resin fills up, so the unit flushes itself with brine and you refill the salt.
A multi-stage shower filter sits between the shower arm and the showerhead. It reduces chlorine, heavy metals and sediment. It reduces calcium and magnesium. It may help limit limescale on the showerhead and fittings. The cartridge lasts 2-6 months in typical home use.
Pick by the problem you actually have. Scale across the whole house is a plumbing job. Skin and hair in the shower is a shower job.
If your number sits in the hard bands, start where you notice it most. We build Hard Water Filters Australia for the bathroom, so your shower water changes first.
Last reviewed September 2026 by Lena Hartman
Health disclaimer: a shower filter is not a medical treatment for eczema or any skin condition. If you have a diagnosed skin condition, consult a dermatologist. We describe what filtration media do to water, not what they do to a diagnosis.
Data note: every figure here names its source and its year. Water utilities publish new reports each year. Open the linked source for the newest number before you act on it.
Frequently Asked Questions
Is soft water better for appliances?
Yes. Soft water holds little calcium and magnesium, so it drops far less scale. Heating elements and spray arms stay clear. Icon Water points out that appliance makers print hardness guidance in their manuals. That guidance exists because hardness changes how the equipment performs.
Is hard water bad for your health?
No. The Australian Drinking Water Guidelines treat hardness as an aesthetic matter, not a health limit. The 200 mg/L figure is there to keep scale out of hot water systems. Hard water is safe to drink at normal Australian levels. Your skin may still feel different.
Which Australian city has the hardest water?
Perth. Water Corporation’s 2024-25 tables put its northern localities highest. Two Rocks averaged 228 mg/L in 2024-25, and Yanchep averaged 198. Perth also holds some of the softest supplies in the same network. Dwellingup averaged 29 mg/L. That spread is why a city average tells you little.
Why does soap not lather in hard water?
Calcium and magnesium react with soap. They form a scum instead of foam. The scum doesn’t dissolve in water. So you add more product to get the same lather. That scum leaves the grey film on your shower screen and the stiffness in your washing.