### Hard water vs Soft water, We all just think -"Water is …

23/10/2018· What is the unit to measure Water Hardness? The unit of water hardness is “grains per gallon” or “grains of hardness”. One grain is equal to 64.799 (64.8) milligrams. Also here is the equation to convert grains per gallon (gpg) to mg/liter-Mg/L = gpg times 17.1