What is the difference between hard and soft water?

Hard water is characterized by high levels of dissolved minerals, particularly calcium and magnesium. These minerals enter the water supply through natural processes, such as the dissolution of limestone, chalk, and gypsum found in the soil and rocks through which the water flows. The high concentration of these minerals is what defines hard water, as compared to soft water, which has lower levels of hardness-causing constituents.

Recognizing the significance of calcium and magnesium is essential for understanding the impact of hard water on various applications, such as household cleaning, plumbing, and water use in boilers. Hard water can lead to scaling, reduced soap efficiency, and potential issues with water-using appliances. Conversely, soft water, often treated to remove these minerals, typically does not present these issues, making the distinction between the two types of water important for both residential and industrial water management.