Which of the following can lead to backpressure conditions?

The occurrence of backpressure conditions is closely associated with a connected elevated distribution system. When water is distributed from an elevated source, such as a water tank or a storage facility situated at a height, the gravitational force can create a significant pressure head. This elevation can cause pressures in the system to become greater than those in the supply mains, particularly during specific operational scenarios, such as when demand increases drastically or when flow patterns change.

In such instances, if there are any cross-connections between potable and non-potable supplies, this difference in pressure can result in backflow, endangering the quality of the potable water supply. Elevated systems can exacerbate this risk by creating conditions where contaminants are inadvertently drawn into drinking water lines if protective measures, like backflow preventers, are not adequately installed or maintained. Therefore, understanding how elevated distribution systems contribute to backpressure is critical for effective backflow management.