What is the primary reason for using a storage tank in a distribution system?

Using a storage tank in a distribution system primarily serves to ensure a reserve of water for peak demands. This is crucial for maintaining a consistent supply of water, especially during periods of high usage when the demand can exceed the immediate supply from the treatment plant or source. By having a reliable reservoir, the system can better manage fluctuations in demand, ensuring that all consumers have access to adequate water without risking shortages or service interruptions.

Additionally, a storage tank can help to balance the system by compensating for variations in production rates and providing the necessary pressure for effective distribution. While other options mention important functions, such as emergency preparedness and water quality, the core function of managing peak demand and ensuring continuous supply is the primary justification for the inclusion of storage tanks in water distribution systems.