What are the two principal chemicals that cause water hardness?

The two principal chemicals that cause water hardness are calcium and magnesium. Water hardness refers to the concentration of calcium and magnesium ions in the water. These minerals originate from natural sources such as limestone, chalk, and gypsum, and they can dissolve into water as it moves through soil and rock formations.

When water contains high levels of calcium and magnesium, it can lead to problems in households and industries, including the formation of scale in pipes and appliances, which affects efficiency and leads to higher maintenance costs. Therefore, the presence of these two elements is a critical factor in assessing water quality and managing water treatment processes.