Mining can greatly affect water quality in nearby areas, especially when mines are abandoned and lead to contamination from tailings and drainage. This study examines the impact of the abandoned Ze & iuml;da lead mine on water sources in the Upper Moulouya region of northwestern Morocco. We aimed to evaluate water quality, understand geochemical processes, and determine the suitability of water for drinking and irrigation. In summer 2021, 21 water samples were collected from rivers, dams, groundwater, and quarry lakes. We analyzed 18 physicochemical and metallic parameters, finding significant variations in ion concentrations. The main ions were ranked as Na+ > Mg2+ > Ca2+ > K+ and HCO3- > Cl- > SO42- > NO3-. Metal concentrations followed the order Zn > Cu > Pb > As > Cd. The Drinking Water Quality Index (DWQI) showed that 95% of the samples were not suitable for drinking. Similarly, the Irrigation Water Quality Indexes (IWQIs) indicated that quarry lakes were unsuitable for irrigation, while groundwater met acceptable criteria. Over 70% of the samples showed no significant metal contamination based on the Heavy Metal Evaluation Index (HEI) and Heavy Metal Pollution Index (HPI). The data suggest that water-rock interactions are the main drivers of hydrochemical changes, with processes like calcite, dolomite, otavite, and cerussite precipitation, as well as the weathering of minerals like halite, starkeyite, and sylvite. To protect water quality and prevent environmental damage, ongoing monitoring and appropriate measures are recommended for the Ze & iuml;da mining area.