This study has been prepared to clarify the environmental impacts of irregular solid waste disposal sites in Duzce. Solid wastes were found in the Melen dam basin, where the drinking water of the Istanbul metropolitan area was provided and poured on the edge of the Kucuk Melen Stream and on alluvium without taking any precautions. Geological and hydrogeological maps of solid waste irregular disposal sites and its surroundings are prepared. In order to determine the groundwater quality in the study area chemical analysis results determined for potability and various usability purposes. The hydraulic connection between the surface and groundwater of irregular solid waste disposal site was evaluated under different environmental conditions and conceptual models were prepared. It has been determined that the solid waste irregular storage site in the study area negatively affects the surface and groundwater quality and the water samples are not suitable for human consumption purposes. As a result, transportation of solid wastes in the drinking water basin from the region to a regular solid waste storage facility or construction of a 45 m deep all-around impermeability curtain has been seen as secure solution methods. Furthermore, in the condition of the leak water level in the environment which is isolated from the surface water and groundwater is below the natural water level, it will have been prevented the water flow out of the storage facility.