In Rabnita and Dubasari districts the aquifers in the strata of Neogene age are used for the water supplies of the local population. The strata are represented by limestones, and in some areas and levels by marls and clays. Regionally, these strata belong to the Lower and Middle Sarmatian stage of Middle and Upper Miocene. In most cases there are no waterproof strata between Lower and Middle Sarmatian limestones, and the rocks of both sub-horizons represent a single, united aquifer. The limestones of Lower and Middle Sarmatian often are almost identical lithologically, and the limit between them is identified only by fauna. In Rabnita district the rocks of Lower Sarmatian are uncovered by the erosion of the River Dniester, and the Middle Sarmatian limestones lie above the level of erosion. Thus, the Middle Sarmatian is drained by water springs and the principal water horizon is located in the rocks of Lower Sarmatian only. In Dubasari district the Lower Sarmatian strata lie below the level of Dniester waters; they show low transmissivity, and these waters are not used exclusively for the supply of population. The principal water horizon is Middle Sarmatian only. The most wells in the district were drilled down until the limit of Lower Sarmatian or even Upper Badenian aquifers, but pump mostly the waters of Middle Sarmatian. There are no waterproof strata between the two Sarmatian horizons, but Middle Sarmatian waters dominate because of higher transmissivity values of the Middle Sarmatian limestones. In Rabnita district there are many wells in and around the district centre proper (Rabnita, Smalena, Harjau). The chemical composition of Lower Sarmatian groundwaters is mixed. The dominating anion is HCO3, with about 40-60%, the second is SO4, with about 25-40%, Cl almost never exceeds 20%. Among the cations, all 3 are presented above 20%, in the majority of wells Na is first, sometimes Ca or Mg. In Varancau, the chemical composition is HCO3-Na-Mg, in Jura HCO3-SO4-Na- Mg, in Ofatinti HCO3-SO4-Mg-Na-Ca, in Crasnencoe HCO3-Cl-Na. The waters are fresh, mineralisation rarely exceeds 1 g/l. In Dubasari district there are wells which pump only the Lower Sarmatian aquifer, with the upper part of the water-bearing strata below the sea level – in Cosnita, Lower Sarmatian is found on -6.8 m. The waters are fresh, mineralisation below 0.75 g/l. In Cosnita, the composition is HCO3-SO4- Ca-Mg-Na, in Dubasari HCO3-Na. In many areas of Dubasari district the wells use both Upper Badenian, Lower and Middle Sarmatian aquifers. In the district centre proper, the chemical data show a mixed, 3-anion and 3-cation composition of groundwaters, with HCO3 on the first place, and dominant Mg and Na among cations. In Tabuleuca, HCO3 is 76% and Na 62%, in Molovata Noua HCO3 stays at about 60-70%, Mg at 25-50% and Na more than 50%. In Cocieri SO4 is dominant among anions at about 35-50%, and Mg at about 40-50%. In Crasnai Vinogradari and Alexandrovca Noua HCO3 is at 50- 60% and Mg at about 60%. In Cosnita the waters of the Middle Sarmatian aquifer show the dominance of HCO3 at 65-70%, Mg at about 35-40%, Na at about 25-40%, and Ca at 25-35%. The mineralisation of the Middle Sarmatian grounwaters in Dubasari varies from 0.5 to 1.35 g/l. In both districts the concentration of Mg very often exceeds normal, about 6-7 mg-equi/l. This, together with some concentration of Ca, makes the waters in the majority of areas and wells minerally hard, in many cases above 8-10 mg-equi/l. Of other components, both Cl and SO4 do not exceed normal quantities established by the standards of state. In both districts the groundwaters used in the communal sector are taken from the first, the uppest aquifer in the pre-Quaternary rock strata.