The document specifies two chemical methods. The first method is applicable to the determination of the mass concentration of calcium in ground water, surface water and drinking water in mass range from 2 mg/l to 100 mg/l (accordingly 0,05 mmol/l to 2,5 mmol/l). A higher calcium range the sample shall be diluted accordingly. The method is applicable to waste water, too, if there are no interfering concentrations of heavy metals. The second method is applicable to the determination of the sum of the concentration of calcium and magnesium in ground water, surface water and drinking water with concentrations of calcium and magnesium higher than 0,05 mmol/l. Sea water and water with comparable high salt contents as well as waste water shall not be examined with this method. In this case DIN EN ISO 7980 (atomic absorption spectrometric method) is suitable, for instance.