Calcium is a mineral, which exists in soil and rock formations such as limestone, dolomite and gypsum. Calcium is present in groundwater depending on the rock formation in the area. While calcium is a mineral needed by the body, drinking water contributes only a small amount of the required daily intake.
Concentrations found as high as 1800 mg/I of calcium in water are reported as causing no health effects.
What do results mean?
Calcium does contribute to aesthetic problem as it contributes to the hardness of the water and build up on pipes which can reduce flow and pressure. It can also reduce the life of certain appliances such as water heaters, dishwashers and washing machines. Calcium analysis can be used to calculate the hardness, which it also made of other minerals including magnesium. The most widely accepted definition of hardness is based upon The United States Geologic Survey and is as follows:
Soft O – 3.5 grains per gallon Moderate 3.5 – 7.0 grains per gallon Hard 7.0 – 10.5 grains per gallon Very Hard 10.5 and over.
Hardness can be reported in grains per gallon or in milligrams per liter. To convert milligrams per liter into grains per gallon simply divide by 17.1. To convert grains per gallon into milligrams per liter simply multiply by 17.1.Low levels of calcium can be helpful, as it can form a coating on pipes, which may prevent corrosion of lead or copper pipes.
How do you test for hardness?
You can easily test for hardness in the field using a colorimetric test, which utilizes a titration. You simply add chemical until a color change occurs and the amount of chemical used is related to the amount of hardness in your sample. Hardness can also be calculated if the amount of calcium and magnesium is known, so most laboratories will run calcium & Magnesium tests and calculate the hardness level. This is the more accurate analysis.
Water Treatment Options
The most common method for treating hard water is using ion exchange also known as a water softener. This method utilizes a tank, which contains resins designed to trap ions. These resins are charged with sodium chloride, which are exchanged for the magnesium and calcium ions. This is a cost effective way to treat water for hardness and has some additional benefits, such as savings in soap and detergents. Since some people are concerns about their sodium intake and softeners will contribute some amount of sodium chloride into the final water, you can also use potassium chloride to regenerate the resin.
There are other technologies, which offer salt-free solutions. While these newer technologies are not as thoroughly tested and proven, they offer other solutions which seem promising.