category_img

Calculator 8 - Water Hardness Calculator

Back to Calculators

Hard waters are as satisfactory for human consumption as soft waters, however, because they require considerable amounts of soap to produce a lather and produce scale in hot-water pipes, heaters, etc. they are often not desirable for a household.

The hardness of waters are commonly classified as follows:

mg/L Degree of Hardness
0 - 75 Soft
75 - 150 Moderately Hard
150 - 300 Hard
300 and up Very Hard

The calculation of the hardness caused by each ion is performed by the following equation:

Hardness (in mg/L) as CaCO3 = M2+ (mg/L) x (100 g/mol CaCO3/ atomic weight of M2+)    

The following calculator determines the hardness of waters based on the concentrations of the divalent cations Ca, Mg, Mn, Fe and Sr.

HARDNESS CALCULATOR 

Concentration

Ca2+     

Mg2+     

Fe2+      

Sr2+      

Mn2+      

*a value must entered in each field (i.e. if none present, enter 0)*

 

Hardness

as mg/L of CaCO3