Water Hardness Scale of Classifications
| grains per gallon (gpg) | milligrams per liter (mg/L) parts per million (ppm) | U.S. Geological Survey Classification | Water Quality Association Classification |
|---|---|---|---|
| < 1.0 | < 17.1 | soft | soft |
| 1 to 3.5 | 17.1 to 60 | soft | slightly hard |
| 3.5 to 7.0 | 60 – 120 | moderately hard | moderately hard |
| 7.0 to 10.5 | 120 – 180 | hard | hard |
| 10.5 + | 180 and over | very hard | very hard |
Table adapted from Water Treatment Fundamentals, prepared and distributed by the Water Quality Association
U.S. Geological Survey Water Hardness Explanation | Water Quality Association Scale Desposits from Hard Water
Water Hardness Map of the United States
Table adapted from and prepared by the United States Geological Survey
Water Hardness from Domestic Wells (2019)
Table adapted from and prepared by the United States Geological Survey
A water softening system is a great investment for any home or business with hard water. The ROI is extremely high due to the various benefits of a water softener.
Water hardness is defined by the concentration of (levels of) minerals like calcium and magnesium. High hardness levels can lead to scaling in pipes and appliances, resulting in costly and sometimes unexpected repairs and inefficiencies. These mineral levels are quantified in mg/L (milligrams per liter) or ppm (parts per million). Hard water contains high concentrations of these minerals, which create scale buildup on plumbing, pipes, fixtures, and appliances. This reduces the effectiveness of water heaters and dishwashers. Soft water has lower mineral levels, making it less prone to scale formation in plumbing and appliances. The degree of water hardness in the United States varies significantly across regions, influenced by local geology, climate, and water sources. Calcium and magnesium enter water systems through the natural weathering of rocks and soil, mainly limestone and gypsum.
