Water Hardness Calculator

Classify water hardness from CaCO₃ concentration.

Classification Hard

Hardness (grains/gal) 8.763

Formula: soft <60, moderate 60–120, hard 120–180, very hard >180

Step-by-step with your numbers:

1. Values used:

2. Hardness = 150 ppm CaCO₃

4. Classification = Hard

5. Hardness = 8.763grains/gal

Did we solve your problem today?

Classify water hardness, expressed as calcium carbonate (CaCO₃).

The math behind it

Soft <60, moderately hard 60–120, hard 120–180, very hard >180 ppm. 1 grain/gallon = 17.118 ppm.

150 ppm → Hard (~8.8 grains/gal).

Why it matters?

Hard water causes scale and reduces soap lathering.