In analytical chemistry, the measure pH (lat. pondus Hydrogenii) is defined as the decimal logarithm of the reciprocal of the hydrogen ion activity (pH=-lg[H+]), i.e. it is an integral index of dissolved hydrogen and OH- group in medium (in our case study, in shallow groundwater). The pH serve as quantitative measure of the acid-base states and ionic equilibrium in groundwater. It mainly depends on the hydrolysis of the salts dissolved in water, the amount of carbonic acid, and the content of various organic acids. Geostatistical analysis of the data shows following: the pH unit has normal distribution in unconfined aquifer. pH change is registered in range of 6.5 - 8.5, and conform to classification elaborated by Posokhov, E.V. (1980), waters are divided into neutral and alkalescent. The limit of background and anomalous values is 7.65, the accuracy of its determining is high (0.5%). This limit is close to the pH = 7.5, which is an intermediate value between neutral and alkalescent waters. This implies that in chemical composition the anomalous values correspond with neutral, and background - with alkalescent groundwater. The digital cartographic model of the pH parameter in groundwater of unconfined aquifer was created. Spatial distribution of neutral and alkalescent water is not a subject to any clear spatial pattern. A tendency of local confinedness of neutral waters to river valleys is traced. Also the relation between acid - base indicator and geochemistry of groundwater is found. Polluted phreatic waters, statistically , are alkaline or geochemical conditions as [OH-]> [H +] is observed. In such circumstances, conditions for migration and accumulation of inorganic pollutants (nitrogen group, complex compounds of sulfates, chlorides, and a whole range of heavy metals), geochemicaly are favorable.