How to Interpret Water Hardness Test Results

• 1). Acquire a water hardness testing kit from a testing supply company. Follow the directions on the water hardness testing kit.
  
  
• 2). Read the results. The hardness of your water will be reported in grains per gallon, milligrams per liter (mg/l) or parts per million (ppm). One grain of hardness equals 17.1 mg/l or ppm of hardness.
  
  
• 3). Interpret the results. water hardness is classified by the U.S. Department of Interior and the Water Quality Association as follows:
  
  Soft : 0 - 1 grains/gal
  
  Slightly hard: 1 - 3.5 grains/gal
  
  Moderately hard: 3.5 - 7.0 grains/gal
  
  Hard: 7.0 - 10.5 grains/gal
  
  Very Hard: 10.5 grains/gal & over
  
  
• 4). Assess your options. If your water has a water hardness of 7.0 grains/gal or more, you may want to soften it. There are two ways to soften your water: packaged water softeners and mechanical water softening units.