Define hardness and causes of hardness

• Hardness of water refers to the concentration of dissolved minerals, mainly calcium and magnesium ions, in a given water supply. 
• Hardness is an important water quality parameter because it affects a water's physical and chemical properties, such as taste, lathering ability, and the ability to form suds.

Causes of hardness

• Natural sources: The main cause of hardness in water is the presence of dissolved minerals, mainly calcium and magnesium ions, from natural sources such as rocks, soil, and groundwater.
• Geographical location: The hardness of water can vary depending on geographical location and source of water supply, with water in areas with hard rock formations, such as limestone and dolomite, typically having higher levels of hardness.
• Groundwater: Groundwater is often higher in hardness compared to surface water sources, such as rivers and lakes, due to the minerals it picks up as it percolates through soil and rock.
• Industrial processes: Some industrial processes, such as mining and drilling, can also contribute to the hardness of water.
• Use of hard water in boilers: The use of hard water in boilers for heating or power generation can lead to scaling and other issues, and can contribute to the overall hardness of the water supply.