The bigger picture
A thoughtful starting point.
Different units can make two water results look unrelated. The tool below converts hardness between mg/L expressed as calcium carbonate and grains per US gallon. It runs in your browser; the value is not sent to us.
This calculator does not select a softener, estimate contamination risk, or certify safety. Use the hardness-testing guide to confirm that your number represents the correct sample point. A complete treatment design needs more than one hardness reading.
