Hard water, explained

If your kettle furs up, your taps grow white crust and your soap never quite lathers, you have hard water. It is one of the most common water complaints in the UK — and one of the easiest to deal with.

What hardness is

Hard water is simply water that has picked up dissolved calcium and magnesium on its way through chalk and limestone. It is not a health risk — hard water is perfectly safe to drink — but it is hard on your home.

What it does

• Limescale builds up in kettles, boilers, showers and washing machines, shortening their lives and pushing up heating bills.
• Soap and detergent work less well, so you use more of both.
• Skin and hair can feel dry after washing, which some people notice more than others.

How to know for sure

A quick hardness strip tells you in seconds whether your water is soft, hard or very hard. A laboratory test gives you the exact figure — useful for sizing a softener or checking one is still working.

What to do about it

Softening and scale protection are well-solved problems: from simple filter jugs and tap filters for drinking water, to inline scale reducers and full softeners that protect the whole house. The right choice depends on how hard your water is and what you want to protect — which is exactly why we suggest testing first. Know your number, then pick the filter that fits.