To assessing the quality of natural mineral waters, one of the most important indicators is the amount of dissolved substances (TDS) or total mineralisation. However, the methodology for its determination is time-consuming and resource-intensive. To determine the TDS of water in the field, the value of its electrical conductivity measured conductometrically is used. This method is quick and easy to perform in the field, but inaccurate in terms of its universality for all types of water. We have developed a rapid method for determining the TDS of natural waters in the field for three common types of water, which can be determined organoleptically by the taste of water: slightly-mineralised, low- and medium-mineralised bicarbonate and chloride waters. The methodology is based on conductometric determination of the electrical conductivity of water and titrimetric determination of one of the main anions – bicarbonates or chlorides – depending on the type of water, followed by calculation of TDS using the developed regression equations. They use constant coefficients for the main water ions for each type. The error in TDS determination is 5…8%, which is significantly less than the error in the conventional method. The rapid method does not take into account the cases of sulphate water and brine. The rapid method for determining the TDS of natural waters in the field can be used for massive research to find new water sources; rapid determination of the level of water mineralisation at different depths during drilling of water wells, etc.