Water hardness is primarily caused by the presence of dissolved minerals, specifically calcium and magnesium. When the concentration of these minerals reaches a certain level, the water is considered "hard."
Here's a breakdown:
- The Culprits: Calcium (Ca2+) and Magnesium (Mg2+) ions are the main drivers of water hardness.
- The Source: These minerals are naturally picked up as water travels through soil and rock formations containing limestone, chalk, dolomite, and other mineral deposits.
- The Threshold: While trace amounts of calcium and magnesium are common, water is officially classified as "hard" when the concentration reaches or exceeds a certain threshold. According to the reference, this threshold is 7 grains per gallon (GPG) or 120 parts per million (PPM).
In simpler terms, if your water has more than 7 GPG or 120 PPM of calcium and magnesium, it's considered hard water. This can lead to various problems, such as scale buildup in pipes and appliances, reduced effectiveness of soaps and detergents, and dry skin and hair.
