Hard water contains relatively high levels of dissolved calcium and magnesium. When heated or allowed to evaporate, these minerals can contribute to scale deposits.
What does hard water affect?
- Kettles and coffee equipment.
- Taps, shower fittings and glassware.
- Appliances that heat water.
- How soap and detergent behave.
Is hard water the same everywhere?
No. Hardness varies substantially by geography and water source. UK households should use current local water-supplier information when making decisions.
Hard water and filters
Some filters are designed primarily for taste and specific contaminants; others are designed to address hardness. Always check the exact claim and the expected result.
Next step
If limescale is your main concern, see our limescale guide and hard-water filter guide.