What it is
Hardness is a measure of dissolved calcium and magnesium, reported as the equivalent amount of calcium carbonate. Water is described as soft, moderately hard or hard depending on the figure.
Where it comes from
Hard water comes from chalk and limestone areas, where the water dissolves minerals as it passes through the rock. Much of eastern and southern England has hard water; upland areas on older rock have soft water.
Why it matters
There is no health-based guideline for hardness; calcium and magnesium are both nutrients. The effects are practical: limescale in kettles, boilers and showers, more soap and detergent needed, and dry skin for some people. Very soft water, on the other hand, is more corrosive to pipework.
What can be done about it
A water softener removes hardness for the whole house, protecting boilers and appliances. Softened water is usually not recommended for drinking by people on a low-sodium diet or for making up infant feeds, so a separate unsoftened tap is normally kept for the kitchen. Pozzani supply and install softeners and can advise on the right size.
Information last reviewed 5 October 2026 by Pozzani Pure Water.