Annual Sprinkler inspection (Approximately 12 systems) Annual Sprinkler Head Inspection. Annual Backflow Inspection. Annual Fire Hydrant Inspection. Sprinkler, Backflow, and Fire Hydrant Inspection Inoperable Deficiency: There are 6 Hydrants on property. The highest Gallons Per Minute Achieve was 650 and the lowest was 200 for building 400. Need to investigate to see if There’s a straightener clogged or an underground valve partially shut.