This paper investigates the influence of pipe material on the quality of water in transmission systems over varying time periods. A comparative study was carried out between two widely used types of water transmission pipes: ductile cast iron pipes with internal cement lining and polyethylene pipes. The physical and chemical properties of the water were analyzed.The two pipe types—ductile cast iron with cement lining and polyethylene—were introduced, and their characteristics were examined. Water samples were collected at various intervals as they passed through these pipes to assess quality parameters.Factors such as concentrations of organic and mineral chemicals, microbial and bacterial content, pH, dissolved oxygen, and other key indicators were measured. The results were analyzed to accurately determine the effect of pipe type and material on water quality over time. Statistical differences and their likely causes are discussed. This study offers valuable insights for selecting optimal pipe materials in water transmission systems, aiding designers and decision-makers in hydrology, and contributing to improved water quality and resource efficiency.