Water Hardness Table
Water Hardness | Softening level | ||||||
|---|---|---|---|---|---|---|---|
ppm | °d | °e | °f | mmol/l (Ca+Mg) | mg/l (Ca) | Range | |
0 | <4 | <5 | <7 | <0.7 | <29 | Soft | H0 |
75 | 4 - 7 | 5 - 9 | 7 - 13 | 0.7 - 1.3 | 29 - 50 |  | H1 |
125 | 7 - 14 | 9 - 17.5 | 13 - 25 | 1.3 - 2.5 | 50 - 100 | H2 | |
250 | 14 - 21 | 17.5 - 26 | 25 - 38 | 2.5 - 3.8 | 100 - 150 | H3 | |
375 | >21 | >26 | >38 | >3.8 | >150 | Hard | H4 |