Which two principal chemicals cause water hardness?

Water hardness primarily arises from the presence of dissolved minerals, specifically calcium and magnesium ions. These two elements are prevalent in many natural water sources, such as rivers, lakes, and groundwater, due to their abundance in geological formations.

When water flows through soil and rock, it can dissolve these minerals, leading to increased levels of calcium and magnesium in the water. As these ions accumulate, water hardness increases, which can affect various aspects of water use, including the effectiveness of soap and detergent and the scaling in pipes and appliances.

Understanding the influence of calcium and magnesium is essential in water treatment processes, home water management, and even in agricultural practices, where water quality can directly impact crop yields and soil health.