As mandated by NFPA25, Quarterly inspections must be performed to ensure all sprinkler valves are not leaking and in good condition. 

15.4.1. Scheduling

To be scheduled every 60 days with your licensed professional already performing the monthly sprinkler inspection.  

15.4.2. Test

All valves shall be inspected quarterly to verify the valve in the open position, not leaking in a good condition, with hand wheels installed and unbroken.