What causes water hardness?

Water hardness is primarily caused by the presence of compounds of calcium and magnesium in the water. These minerals dissolve into the water from various geological sources, such as limestone and chalk deposits. When water percolates through these rocks, it picks up the calcium and magnesium ions, which then contribute to the overall hardness of the water.

Hard water is characterized by higher levels of these minerals, which can lead to various issues, such as scaling in pipes and appliances, as well as affecting the effectiveness of soaps and detergents. Thus, the connection between water hardness and the presence of calcium and magnesium is fundamental to understanding water chemistry and its implications for both domestic use and ecological health.