Water Hardness Scale August 6, 2022 413 × 160 Hardness of Water From: https://sciencefaircenter.com/wp-content/uploads/2012/12/TotHardnessITSFCScale4x722.jpg https://sciencefaircenter.com/wp-content/uploads/2012/12/TotHardnessITSFCScale4x722.jpg