Hard water refers to water that contains high levels of dissolved minerals, primarily calcium (Ca²⁺) and magnesium (Mg²⁺) ions. These minerals are naturally picked up by water as it passes through soil and rock, especially limestone, chalk, or gypsum, which are rich in calcium and magnesium.
Hardness is typically expressed in terms of calcium carbonate (CaCO₃) concentration, measured in milligrams per liter (mg/L) or grains per gallon (gpg).
- Soft Water: 0–60 mg/L CaCO₃
- Moderately Hard Water: 61–120 mg/L CaCO₃
- Hard Water: 121–180 mg/L CaCO₃
- Very Hard Water: Over 180 mg/L CaCO₃
Common Issues Caused by Hard Water:
- Appliance Efficiency: Reduces the efficiency of water heaters, dishwashers, and washing machines due to limescale buildup.
- Plumbing Problems: Can clog pipes over time, leading to reduced water flow and increased maintenance.
- Skin and Hair: May leave a residue on skin and hair, making them feel less clean or causing dryness.
