Is My Water Hard or Soft? Check by Postcode

Enter your UK postcode in the search box above. We'll instantly show you the water hardness level for your area in mg/l CaCO₃, along with a classification from Soft to Very Hard. You can also look for signs at home: limescale buildup on taps, in kettles, or around showerheads indicates hard water.

Hard water contains high levels of dissolved minerals, primarily calcium and magnesium. It is measured in milligrams per litre (mg/l) of calcium carbonate (CaCO₃). Water above 200 mg/l is classified as Hard, while water below 50 mg/l is Soft. Hard water is safe to drink but can cause limescale buildup in appliances and pipes.

Water hardness is classified on a scale: Soft (0–50 mg/l), Moderately Soft (50–100 mg/l), Slightly Hard (100–150 mg/l), Moderately Hard (150–200 mg/l), Hard (200–300 mg/l), and Very Hard (300+ mg/l). Most of South East England has hard or very hard water, while Scotland, Wales, and Northern England tend to have softer water.

Hard water is safe to drink and may even provide a small amount of dietary calcium and magnesium. The World Health Organisation states there is no convincing evidence that hard water causes adverse health effects. However, some people with sensitive skin or eczema may notice that very hard water can aggravate dryness.

There are several options: a whole-house water softener (ion exchange system) is the most effective solution, typically costing £400–£1,500 installed. For drinking water only, a jug filter or under-sink filter can reduce hardness. For appliances, regular descaling with citric acid or white vinegar helps manage limescale buildup.