1. What is Water Hardness?

Water hardness is a measure of the concentration of calcium and magnesium ions in water, expressed as calcium carbonate (CaCO₃) equivalent. It's important for determining water softener requirements and understanding scaling potential.

2. How Does the Calculator Work?

The calculator uses these equations:

Where:

• Ca — Calcium concentration in mg/L
• Mg — Magnesium concentration in mg/L
• 2.497 — Conversion factor for calcium to CaCO₃ equivalent
• 4.118 — Conversion factor for magnesium to CaCO₃ equivalent
• 17.1 — Conversion factor from mg/L to grains per gallon

3. Importance of Water Hardness Calculation

Details: Knowing water hardness is essential for sizing water softeners, preventing scale buildup in pipes and appliances, and determining appropriate detergent usage.

4. Using the Calculator

Tips: Enter calcium and magnesium concentrations in mg/L. Values must be ≥0. The calculator provides results in both mg/L as CaCO₃ and grains per gallon.

5. Frequently Asked Questions (FAQ)

Q1: What is considered hard water?
A: Generally, 0-60 mg/L is soft, 61-120 mg/L is moderately hard, 121-180 mg/L is hard, and >180 mg/L is very hard.

Q2: Why convert to grains per gallon?
A: Water softener capacity is typically rated in grains, so this unit is more practical for softener sizing.

Q3: Should I test my water hardness?
A: Yes, especially if you notice scale buildup, have difficulty lathering soap, or are considering a water softener.

Q4: Are there other hardness minerals?
A: While calcium and magnesium are primary, other divalent cations can contribute, but usually in minor amounts.

Q5: How often should hardness be measured?
A: For municipal water, once a year is sufficient. For well water, test every 6 months as levels can vary.