This study aims to characterize the contamination of raw water from the Sidi Abdelli dam, located in the northeast of the Tlemcen province (northwestern Algeria), by trace metal elements. It assesses water quality, contamination risks, and the toxicity associated with the presence of heavy metals. The analyzed elements include cadmium (Cd), lead (Pb), nickel (Ni), iron (Fe), manganese (Mn), aluminum (Al), arsenic (As), barium (Ba), chromium (Cr), and copper (Cu), with the objective of proposing appropriate corrective measures. The analysis of trace metal concentrations over a period of more than a decade (2008–2022) reveals a significant enrichment, particularly in cadmium, whose concentration reaches 0.009 mg/L, exceeding the Algerian standard of 0.005 mg/L. A statistical treatment of the data was applied to heavy metal analyses to develop a predictive model of their spatiotemporal variability. This approach enables optimized pollution monitoring, identification of contamination sources, and mitigation of associated ecotoxicological and health impacts.