Hard water causes limescale, dry skin, and poor soap lather. But how do you know if your tap water is actually hard? There are four easy ways to check.
You don’t need a lab. You don’t need a plumber. You need five minutes and either a bar of soap or a test strip.
Method 1: Look for Visual Signs Around the House
Your home tells you a lot before you run any test.
Check these spots:
- Inside your kettle. A white or chalky lining is calcium carbonate scale. It forms when hard water is heated and minerals drop out of solution.
- Your shower head. White crusty deposits on the nozzles are limescale. Very common in Perth and Adelaide homes.
- Shower screen or tiles. Hard water dries and leaves white mineral spots. Plain water won’t wipe them off.
- Dishes and glasses. Cloudy patches on clean glassware after the dishwasher mean hard water.
- Taps and fittings. A white powdery residue around the base is a strong sign.
If you see three or more of these, your water is almost certainly hard. No further test needed.
Some cities are much worse than others. Our what causes hard water guide explains the geology behind it.
Method 2: The Soap Test
This is the quickest DIY test. It takes about two minutes.
What you need: A clean clear bottle with a lid. Pure liquid soap (no moisturisers or detergent). Tap water.
Steps:
1. Fill the bottle about one-third with tap water. 2. Add 10 drops of pure liquid soap. 3. Put the lid on and shake for 10 seconds. 4. Look at the result.
What the result means:
If the water goes cloudy and produces very few bubbles, your water is hard. The calcium reacts with the soap and kills the lather.
Clear water with lots of white bubbles means soft water.
This test tells you hard or soft. It doesn’t give you a number. For a number, use Method 3.
Method 3: Test Strips
Test strips give you an actual hardness reading in mg/L (or ppm). They’re accurate enough for home use.
You can buy them at hardware stores, pool shops, or online. A pack of 50 strips costs about $10-15 AUD.
Steps:
1. Fill a clean glass with cold tap water. 2. Dip a test strip for 3-5 seconds. 3. Remove and hold flat. Don’t shake off excess water. 4. Wait the time shown on the pack. Usually 15-30 seconds. 5. Compare the colour to the chart on the packaging.
Reading the result:
| Hardness | mg/L range |
|---|---|
| Soft | 0-60 mg/L |
| Moderately hard | 60-120 mg/L |
| Hard | 120-200 mg/L |
| Very hard | above 200 mg/L |
Most Perth and Adelaide households test in the 80-200 mg/L range. Some northern Perth suburbs test above 200 mg/L.
Method 4: Check Your Water Authority
You can look up your suburb’s water hardness directly. Australian water authorities publish this data online.
- Perth: Water Corporation WA – watercorporation.com.au – search “water quality data”
- Adelaide: SA Water – sawater.com.au – search “drinking water quality”
- Melbourne: Melbourne Water – melbournewater.com.au – search “water quality”
- Sydney: Sydney Water – sydneywater.com.au – search “water quality reports”
- Brisbane: Seqwater – seqwater.com.au – search “drinking water quality”
Type in your suburb. The report shows hardness as calcium carbonate in mg/L.
This is the most accurate method. The data comes straight from your supplier. For a city-by-city overview, see our guide to hard water hotspots in Australia.
Understanding Your Result
A reading above 60 mg/L means your water is moderately hard or worse.
At 120 mg/L or above, limescale, soap scum, and skin effects are more noticeable. Above 200 mg/L puts you in the very hard category. Parts of Perth’s northern suburbs fall here.
Our hard water vs soft water guide breaks down what each level means.
What to Do If Your Water Is Hard
You have two main options.
Whole-house water softener. Treats all the water coming into your home. Uses ion exchange to remove calcium and magnesium. Needs professional installation and ongoing salt.
Shower filter. Targets water at the shower head. Reduces calcium, magnesium, chlorine, and heavy metals. Installs in minutes. No plumbing. Cartridge swap every 2-6 months.
For skin and hair, the shower filter is the faster and cheaper fix. The POWERBOX™ filter is built for Australian hard water.
Your water tested hard? See the shower filter for hard water and check if it fits.
FAQ
How do you test for hard water at home?
The quickest method is the soap test. Add liquid soap to tap water in a bottle and shake. Cloudy water with poor bubbles means hard water. For an actual reading, use a test strip from a hardware store. You can also look up your suburb’s water quality data on your water authority’s website.
What are the signs of hard water in your home?
White chalky scale inside your kettle. Limescale on your shower head and screen. Spotty, cloudy glasses after washing. White powder around tap bases. Soap that lathers poorly. Three or more of these signs point strongly to hard water.
What hardness level is considered hard water in Australia?
The Australian Drinking Water Guidelines classify water as hard at 120-200 mg/L and very hard above 200 mg/L. Water between 60-120 mg/L is moderately hard. Perth and Adelaide average 96-103 mg/L city-wide. Some northern Perth suburbs reach 228 mg/L.
Can I use a pool test strip to test water hardness?
Pool test strips often measure calcium hardness, which is part of total hardness. They can give a rough reading. Dedicated water hardness strips are more accurate and cost about $10-15 AUD for 50 strips.
What should I do if my water tests hard?
A shower filter is the fastest and most affordable fix for skin and hair issues. It installs in minutes with no plumbing and reduces calcium, magnesium, and chlorine at the shower head. For whole-house treatment, a water softener is the more thorough option.