SUMMARY
The present study proposes to control and follow the different stages of realization of three (03) water boreholes in the Congolese coastal sedimentary basin of Pointe-Noire.The depths reached by the three drill holes are respectively 72 m for the Kounda borehole, 65 m for the “Ngoyo plaine” borehole and 52.5 m for the “Ngoyo commune” borehole. They capture the deep aquifer (AQ-2) of the multilayer aquifer system in the Pointe Noire region.Well tests carried out on two of these boreholes show that the critical flows are not reached and the maximum operating flow rates are 6 m3/h for the “Ngoyo commune” and 6.53 m3/h for the Kounda.The physicochemical quality of the groundwater, shows that these waters are drinkable. The projection of the chemical analyzes on the Piper triangular diagram shows that these waters are of the calcium and magnesium bicarbonate family. The water aggressiveness from the Langelier and Riznar stability indices and the saturation indices with respect to the different mineral phases, shows that the groundwater is corrosive and can therefore attack the metal equipment of the dewatering column of these boreholes.