What does a mainline shutoff valve typically control?

A mainline shutoff valve is a crucial component in an irrigation system, responsible for controlling the entire flow of water throughout the system. When this valve is closed, it stops the water supply to all zones and irrigation components downstream of the valve. This feature is essential for maintenance and repair work, as it allows the entire system to be shut down without affecting other systems or surrounding areas.

When skilled technicians need to perform checks or repairs, having the ability to shut off the water supply completely ensures there is no disruption of service or water loss. Therefore, the mainline shutoff valve serves not only as a safety measure but also enhances the flexibility and control over the irrigation system as a whole.

This contrasts with other options, such as regulating pressure or managing flow to specific zones; these functions are typically handled by different valves or components within the system rather than the mainline shutoff valve itself.