If your kettle furs up, your soap won't lather, and your shower screen is permanently cloudy, you're likely living with hard water. Hardness is rarely a health problem — but it's expensive, shortening the life of hot water systems and appliances and quietly narrowing your pipes with scale.
Hardness is common in bore water safety assessments — groundwater picks up calcium and magnesium from the rock it flows through. Tank water, by contrast, is naturally soft (see our tank water safety guide), and can even be too soft, making it corrosive.
What Hardness Means in Your Results
Hardness is usually reported as mg/L of calcium carbonate (CaCO3). As a general guide:
| Hardness (mg/L CaCO3) | What It Means |
|---|---|
| Under 60 | Soft — lathers well, but can be corrosive to pipes |
| 60 – 200 | Good range for most households |
| 200 – 500 | Hard — increasing scale build-up and soap issues |
| Over 500 | Very hard — significant scale, appliance wear and taste effects |
The Australian Drinking Water Guidelines explained treat hardness as an aesthetic and operational issue rather than a health limit — but sustained hardness above the guideline level should be addressed before it costs you a hot water system.
Signs of Hard Water
- White, crusty scale on kettles, taps and shower heads
- Soap that won't lather, and soap scum rings in the bath
- Stiff, scratchy laundry
- Reduced hot-water flow over time (scaled pipes and elements)
- Cloudy film on glassware and shower screens
Testing and Treating Hard Water
A laboratory test measures total hardness alongside calcium, magnesium, alkalinity and pH — together these tell you not just how hard your water is, but how aggressively it will scale. Our guide on how to test your water covers what's involved.
If hardness is the problem, common approaches include:
- Ion-exchange water softeners — the standard fix for genuinely hard bore water
- Scale-inhibiting filters — reduce scale formation without removing minerals
- Point-of-use filtration — protect a single appliance like a coffee machine or hot water system
As always: test first. Softening water that isn't hard wastes money, and very soft water brings its own corrosion problems.
Frequently Asked Questions
What is water hardness?
Hardness is the amount of dissolved calcium and magnesium in your water. Hard water isn't a health risk at normal levels, but it causes scale build-up in pipes, hot water systems and appliances, and stops soap lathering properly.
What hardness level is considered a problem?
The Australian Drinking Water Guidelines note that hardness above about 200 mg/L (as calcium carbonate) starts causing noticeable scale, while under 60 mg/L water can be corrosive. Between those is the comfortable zone for most households.
Does boiling water remove hardness?
Boiling removes only 'temporary' hardness and actually concentrates the scale in your kettle — that white crust is the hardness coming out of solution. Softening or scale-management systems are the practical fix for hard water.
Ready to measure your water hardness?
Get your hardness, calcium, magnesium and pH in one plain-English report — measured against the Australian Drinking Water Guidelines.
