This part of the standard specifies a method for the titrimetric determination of carbonate alkalinity in natural and drinking water. The method is intended for samples with a carbonate alkalinity between 0.01 mmol/l and 4 mmol/l. For samples containing higher concentrations of alkalinity, a smaller test portion can be used for analysis. The endpoint detection, using a pH-meter is less prone to interferences than the use of the indicator.