Hardness Converter

Convert between mg/L and grains per gallon, with a general hardness category.

Convert between mg/L and grains per gallon.

Value

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Conversion: 1 grain per gallon = 17.1 mg/L (as CaCO3). Category labels are general hardness classifications, not a water-safety diagnosis.

Disclaimer: All results are estimates for planning only. County and state rules govern — check with your local authority.