Water Hardness Test Results Guide

What this test measures

Hardness measures the dissolved calcium and magnesium in your water. It’s the UK’s most common water complaint — the cause of furred kettles, scaled boilers, stiff laundry, soap scum and spotted glassware.

The UK standard

There is no legal limit for hardness in UK drinking water — hard water is safe to drink. It simply varies hugely by region: much of the South East and East of England runs hard to very hard, while Scotland, Wales and the North West are mostly soft.

Reading your strip

Dip a strip into your sample for two seconds, hold it level and wait 30 seconds. Match the hardness pad against the colour chart on your instructions card and read off the closest band. Strips give you a clear range rather than a lab-precise number — exactly what you need for spotting problems and tracking changes over time.

What to do next

• Confirm it first. One strip is a snapshot — re-test with a fresh strip and a fresh sample before acting on a result.
• Hard reading? Descale appliances regularly, and if you’re weighing up a softener or scale filter, test before and after so you can see it working.
• Already own a softener? A hardness strip is the quickest way to check it’s actually doing its job — test the softened tap against an unsoftened one.
• Thinking about a filter? Test before and after fitting it so you can see exactly what it changed.