Treated-water reservoirs and raw-water reservoirs serve different roles in a water supply system. A raw-water reservoir stores untreated water collected from natural sources such as rivers, lakes, or groundwater. In the case of desalination, it might hold seawater or brackish water before it enters the treatment process. Because this water has not yet been purified, the design of raw-water reservoirs focuses more on volume, sediment control, and minimizing contamination rather than meeting drinking water standards.
Treated-water reservoirs, on the other hand, hold water that has already gone through desalination or another purification process and is ready for distribution to consumers. Since the water is meant for direct use, these reservoirs must meet strict hygiene and safety requirements. They are often lined, covered, or otherwise protected to prevent contamination, and they are regularly monitored for disinfectant levels, microbial safety, and chemical balance.
