While surface water passes through soils containing limestone and gypsum, calcium is mixed into these waters. Depending on the source of the water and the level of treatment applied, water may have a calcium concentration of zero to hundreds of mg / l. Low calcium carbonate content in drinking water causes corrosion of water distribution systems and metal pipes. High concentrations of calcium salts, on the other hand, cause heating boilers, heating pipes and water pipes to be covered with a calcium carbonate layer and damage the heating systems.

Calcium is an element that increases total hardness in drinking and utility water. A number of methods are employed to remove this calcium hardness, such as chemical softening or electrodialysis. Various methods are also used to determine the amount of calcium. Among these methods, atomic absorption method gives very sensitive results. In addition, permanganate titrimetric method and EDTA titrimetric method are widely used for routine controls. The EDTA titration method has become the preferred method for general use in terms of its simple and fast results. In this method, ethylenediaminetetraacetic acid or its salts (EDTA for short) is first combined with calcium when calcium and magnesium are both added to water. When the pH is sufficiently high, magnesium precipitates as magnesium hydroxide and calcium is determined directly by the EDTA titreric method. Briefly, calcium is determined by means of an indicator which merges only with calcium at high pH.

In the authorized laboratories, titrimetric determination of calcium in drinking and potable water is carried out within the scope of chemical analyzes. A few standards considered in these studies are:

• TS EN 16003 Chemicals for the treatment of drinking and domestic water - Calcium magnesium carbonate
• TS 2879 Water analysis methods - Determination of calcium and magnesium content