While landfilling remains the most economically viable and commonly employed method of waste disposal, it poses potential risks of environmental degradation, including foul odor emission, biogas production, and the generation of leachates carrying a significant pollution load. Leachates, upon infiltrating the subsoil, contribute to a profound degradation of groundwater. This study focuses on assessing the impact of leachates from the public landfill of Bouguerguer (wilaya of Guelma) on groundwater and surface water. Two sampling campaigns were conducted, with the first involving 5 samples and the second comprising 8 samples, both carried out in 2018. Analytical results reveal that water sourced from wells, springs, and downstream surface water from the technical landfill Bouguerguer is heavily contaminated with organic matter and metallic trace elements (Cr⁺⁶, Pb⁺, Fe⁺³, and Ni). Levels of organic matter (BOD5: 50 mg/l - 10 mg/l, dissolved oxygen: 0.5-9 mg/l) are notably elevated in surface and groundwater, respectively. Additionally, concentrations of trace metal elements (Cr⁺⁶: 0.075-2.45 mg/l, Pb⁺: 0.03-1.16 mg/l, Fe⁺³: 0.006-7.07 mg/l, Ni⁺: 0.29-25 mg/l) significantly surpass the standards set by the World Health Organization (WHO). Consequently, these findings substantiate our hypothesis that degraded groundwater and surface water contribute significantly to the prevalence of diseases in Guelma Wilaya. This study emphasizes the urgent need for local authorities to implement preventive measures to mitigate pollution and to rehabilitate the landfill in accordance with international standards.