How long must pressure exist for it to be called constant pressure?

• A. 6 hours
• B. 24 hours
• C. 12 hours
• D. 48 hours

Answer: (C)

Constant pressure means the pressure remains essentially the same within the required tolerance for a sustained period, showing the system can hold the set point despite normal cycling and small disturbances. In this context, twelve hours is the minimum duration used to declare pressure constant because it’s long enough to catch fluctuations from pumps turning on and off, valve operations, leaks, or other minor changes, while still being practical for field testing. Six hours could miss later drift, while twenty-four or forty-eight hours are more lengthy than needed for typical irrigation work and would slow the process.