What can be inferred if residual pressure drops significantly?

A significant drop in residual pressure typically indicates that there is either an increase in water demand or a leak within the system. When residual pressure decreases, it suggests that the available pressure to maintain the flow of water throughout the system is diminished. This situation can arise when there is an unexpected draw from the system, such as a sudden increase in demand due to multiple hydrants being opened or fire operations requiring large volumes of water.

Alternatively, a leak in the water distribution system can also cause a pressure drop as water escapes the system before it reaches the end users. In either case, the critical understanding is that a significant drop in residual pressure may hinder the ability to deliver sufficient water during emergencies, which is vital for firefighting and other necessary operations.