Drinking water remains a scarce resource in many African countries. The quality of water comes from wells/river was studied through the global parameters (Temperature, T; Potential of hydrogen, pH; Electrical conductivity, EC; Dissolved oxygen, O2 diss; Total Suspended Solids, TSS; Salinity, NaCl; and ionic species, Xn). The samples were collected during wet season, in four wells and the river of Nzeng-Ayong Dragages district (Libreville, Gabon). Physical parameters (T, pH, EC and O2) were evaluated in situ, using a multi-parameter device (420-SET-G). TSS were determined after the dewatering step of the raw sample in a filtration cell equipped with a 0,45 µm filter membrane, and Salinity, estimated by colorimetric titration. Finally, mineral pollutants such as (Ba2+, Ca2+, Cl-, NO3-, PO43-, SO42-) and total iron (Fe2+, Fe3+) were evaluated by spectrophotometry, Hach DR 3900. Results show that, the average pH of wells’ water is close to 6.18±1.32 (acid water) while that pH of water from river is neutral (7.23±0.12). EC and dissolved O2 of wells are respectively 184.20±15.78 μS/cm and 8.93±0.97 mg O2/L whereas in the river the values are 37.98±0.85 μS/cm and 7.57±0.39 mg d’O2/L. The ion analysis shows that the two resources are almost not polluted by chemical species other than Ba2+ and PO43-. Pollution ranging between 4.75±1.71 and 4.33±1.15 mg/L of Ba2+, then between 1.31±1.13 and 2.77±2.07 mg/L of PO43- for wells and river, which the concentration is above of the maximum required (0.7 mg/L of Ba2+ and 2 mg/L of PO43-). The structure of soil and the anthropogenic releases could be explaining this alteration. Finally, household bleach treatment has a benefit effect on the reduction of the pollution, with the exception of TSS and Nitrates. This study will be extended to other sites and supplemented by microbiological tests, in order to map areas at risk.