Hard water is defined as greater than what mg/L as CaCO3?

Hard water is defined as greater than what mg/L as CaCO3?

• A. > 60 mg/L
• B. > 120 mg/L
• C. > 200 mg/L
• D. > 300 mg/L

Answer: (B)

Hardness measures how many minerals, mainly calcium and magnesium, are dissolved in water. It’s expressed as milligrams per liter of calcium carbonate equivalents (mg/L as CaCO3) so different minerals can be compared on the same scale. In many water-treatment contexts, water is considered hard when its total hardness exceeds about 120 mg/L as CaCO3. Below that, water is typically classified as soft to moderately hard. So a value greater than 120 mg/L as CaCO3 is the threshold for hard water.

Hardness measures how many minerals, mainly calcium and magnesium, are dissolved in water. It’s expressed as milligrams per liter of calcium carbonate equivalents (mg/L as CaCO3) so different minerals can be compared on the same scale. In many water-treatment contexts, water is considered hard when its total hardness exceeds about 120 mg/L as CaCO3. Below that, water is typically classified as soft to moderately hard. So a value greater than 120 mg/L as CaCO3 is the threshold for hard water.