Water Hardness - How to Check for Hard Water

The following is a list of steps that you can take to test your water for hardness:


  • If you live in a municipal area, check with your local water company.

  • If you live in a rural area, or some suburban areas, contact your local water company or a county extension agent.

  • Have your water tested by a laboratory. You can have your household tap water tested for hardness, dissolved solids, iron, PH, and amount of corrosiveness by an independent, EPA certified laboratory. Water Softener - Determining Your Water Hardness

What is considered hard water?


  • Soft water is 0-3 gpg (grains per gallon).

  • Medium water is 3-7 gpg.

  • Hard water is 7-12 gpg.  Anything over 12 gpg is very hard, and a water softener is recommended.

If you have the hardness in "parts per million" (PPM) or "milligrams per liter" (MgPL) and need to convert to "grains per gallon" (GPG):


  • PPM / MgPL to GPG: Divide by 17.118.

  • GPG to PPM or MgPL: Multiply by 17.118.

  • Example: 300 PPM divided by 17.118 = 17.5 GPG

  • Note: "Milligrams per liter" is the same as "parts per million".  


View a short "What is Hard water?" video: