Water hardness is rated by GPG – grains per gallon, and hard water, higher than 1 GPG includes 85% of the country. The amount of hardness will vary from slight to extreme, see map.

• Soft water – less than 1 grain per gallon
• Slightly hard – 1 to 3.5 grains per gallon
• Moderately hard – 3.5 to 7 grains per gallon
• Hard – 7 to 10.5 grains per gallon
• Very hard – 10.5 and higher grains per gallon

Rain water dissolves minerals present in rocks as it passes though the ground down to the water table, aquifers and wells. Carbon dioxide being heavier than air also combines with rain water underground and helps convert the carbonates of calcium and magnesium into bicarbonates. These bicarbonates being soluble in water cause hardness. Soap and detergents have an ionic nature, when they dissolve in hard water, each soap molecule reacts with any calcium ions, limits the formation of lather and instead forms precipitates or scum. This scum essentially renders the detergent ineffective, so much more soap is needed to clean if used with hard water. More soap means more buildup of scum. This wreaks havoc on your pipes, dishwasher, washing machine, hot water heater and any other household item that uses water.